Lincoln Electric Welder SVM149 A User Manual

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SVM149-A  
October, 2006  
PRO-CUT 25  
For use with machine code numbers 10661  
Safety Depends on You  
Lincoln arc welding and cutting  
equipment is designed and built  
with safety in mind. However,  
your overall safety can be  
increased by proper installation  
. . . and thoughtful operation on  
your part. DO NOT INSTALL,  
OPERATE OR REPAIR THIS  
EQUIPMENT WITHOUT READ-  
ING THIS MANUAL AND THE  
SAFETY PRECAUTIONS CON-  
TAINED THROUGHOUT. And,  
most importantly, think before  
you act and be careful.  
SERVICE MANUAL  
Copyright © 2006 Lincoln Global Inc.  
• World's Leader in Welding and Cutting Products •  
• Sales and Service through Subsidiaries and Distributors Worldwide •  
Cleveland, Ohio 44117-1199 U.S.A. TEL: 1-888-935-3877 FAX: 216.486.1751 WEB SITE: www.lincolnelectric.com  
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ii  
ii  
SAFETY  
4.c. When not cutting or gouging, make certain no part of the elec-  
trode circuit is touching the work or ground. Accidental contact  
can cause overheating and create a fire hazard.  
FOR ELECTRICALLY  
powered equipment.  
6.a. Turn off input power using the disconnect  
switch at the fuse box before working on the  
equipment.  
4.d. Do not cut or gouge tanks, drums or containers until the proper  
steps have been taken to insure that such procedures will not  
cause flammable or toxic vapors from substances inside. They  
can cause an explosion even though they have been “cleaned.”  
For information purchase “Recommended Safe Practices for  
the Preparation for Welding and Cutting of Containers and  
Piping That Have Held Hazardous Substances”, AWS F4.1 from  
the American Welding Society (see address above).  
6.b. Install equipment in accordance with the U.S. National  
Electrical Code, all local codes and the manufacturer’s rec-  
ommendations.  
6.c. Ground the equipment in accordance with the U.S. National  
Electrical Code and the manufacturer’s recommendations.  
4.e. Vent hollow castings or containers before heating, cutting or  
gouging. They may explode.  
4.f. Do nor fuel engine driven equipment near area where plasma  
cutting or gouging.  
PLASMA ARC can injure.  
4.g. Sparks and spatter are thrown from the plasma arc. Wear safe-  
ty glasses, ear protection and oil free protective garments such  
as leather gloves, heavy shirt, cuffless trousers, high shoes  
and a cap over your hair. Wear ear plugs when cutting or goug-  
ing out of position or in confined places. Always wear safety  
glasses with side shields when in a cutting or gouging area.  
7.a. Keep your body away from nozzle and  
plasma arc.  
7.b. Operate the pilot arc with caution. The pilot arc is capable of  
burning the operator, others or even piercing safety clothing.  
4.h. Connect the work cable to the work as close to the cutting or  
gouging area as practical. Work cables connected to the build-  
ing framework or other locations away from the cutting or goug-  
ing area increase the possibility of the current passing through  
lifting chains, crane cables or other alternate circuits. This can  
create fire hazards or overheat lifting chains or cables until they  
fail.  
ELECTRIC AND MAGNETIC FIELDS  
may be dangerous  
8.a. Electric current flowing through any conduc-  
tor causes localized Electric and Magnetic Fields  
(EMF). Cutting or gouging current creates EMF  
fields around torch cables and cutting machines.  
CYLINDER may explode  
if damaged.  
8.b. EMF fields may interfere with some pace-  
makers, so operators having a pacemaker  
should consult their physician before cutting or  
5.a. Use only compressed gas cylinders contain-  
ing the correct gas for the process used and  
properly operating regulators designed for the  
gas and pressure used. All hoses, fittings, etc.  
should be suitable for the application and maintained in good  
condition.  
gouging.  
8.c. Exposure to EMF fields during cutting or gouging may have  
other health effects which are now not known.  
8d. All operators should use the following procedures in order to  
minimize exposure to EMF fields from the cutting or gouging  
circuit:  
5.b. Always keep cylinders in an upright position securely chained  
to an undercarriage or fixed support.  
5.c. Cylinders should be located:  
• Away from areas where they may be struck or subjected to  
physical damage.  
• A safe distance from plasma cutting or gouging, arc weld-  
ing operations and any other source of heat, sparks,  
or flame.  
8.d.1. Route the torch and work cables together - Secure  
them with tape when possible.  
8.d.2. Never coil the torch cable around your body.  
8.d.3. Do not place your body between the torch and  
work cables. If the torch cable is on your right side,  
the work cable should also be on your right  
side.  
5.d. Never allow any part of the electrode, torch or any other elec-  
trically “hot” parts to touch a cylinder.  
5.e. Keep your head and face away from the cylinder valve outlet  
when opening the cylinder valve.  
8.d.4. Connect the work cable to the workpiece as close as  
possible to the area being cut or gouged.  
5.f. Valve protection caps should always be in place and hand  
tight except when the cylinder is in use or connected for use.  
8.d.5. Do not work next to cutting power source.  
5.g. Read and follow the instructions on compressed gas cylin-  
ders, associated equipment, and CGA publication P-l,  
“Precautions for Safe Handling of Compressed Gases in  
Cylinders,”available from the Compressed Gas Association  
1235 Jefferson Davis Highway, Arlington, VA 22202.  
Apr. ‘93  
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iii  
iii  
SAFETY  
6. Eloigner les matériaux inflammables ou les recouvrir afin de  
PRÉCAUTIONS DE SÛRETÉ  
prévenir tout risque d’incendie dû aux étincelles.  
Pour votre propre protection lire et observer toutes les instructions  
et les précautions de sûreté specifiques qui parraissent dans ce  
manuel aussi bien que les précautions de sûreté générales suiv-  
antes:  
7. Quand on ne soude pas, poser la pince à une endroit isolé de  
la masse. Un court-circuit accidental peut provoquer un  
échauffement et un risque d’incendie.  
8. S’assurer que la masse est connectée le plus prés possible de  
la zone de travail qu’il est pratique de le faire. Si on place la  
masse sur la charpente de la construction ou d’autres endroits  
éloignés de la zone de travail, on augmente le risque de voir  
passer le courant de soudage par les chaines de levage,  
câbles de grue, ou autres circuits. Cela peut provoquer des  
risques d’incendie ou d’echauffement des chaines et des  
câbles jusqu’à ce qu’ils se rompent.  
Sûreté Pour Soudage A L’Arc  
1. Protegez-vous contre la secousse électrique:  
a. Les circuits à l’électrode et à la piéce sont sous tension  
quand la machine à souder est en marche. Eviter toujours  
tout contact entre les parties sous tension et la peau nue  
ou les vétements mouillés. Porter des gants secs et sans  
trous pour isoler les mains.  
b. Faire trés attention de bien s’isoler de la masse quand on  
soude dans des endroits humides, ou sur un plancher met-  
allique ou des grilles metalliques, principalement dans  
les positions assis ou couché pour lesquelles une grande  
partie du corps peut être en contact avec la masse.  
c. Maintenir le porte-électrode, la pince de masse, le câble de  
soudage et la machine à souder en bon et sûr état defonc-  
tionnement.  
9. Assurer une ventilation suffisante dans la zone de soudage.  
Ceci est particuliérement important pour le soudage de tôles  
galvanisées plombées, ou cadmiées ou tout autre métal qui  
produit des fumeés toxiques.  
10. Ne pas souder en présence de vapeurs de chlore provenant  
d’opérations de dégraissage, nettoyage ou pistolage. La  
chaleur ou les rayons de l’arc peuvent réagir avec les vapeurs  
du solvant pour produire du phosgéne (gas fortement toxique)  
ou autres produits irritants.  
d.Ne jamais plonger le porte-électrode dans l’eau pour le  
refroidir.  
e. Ne jamais toucher simultanément les parties sous tension  
des porte-électrodes connectés à deux machines à souder  
parce que la tension entre les deux pinces peut être le total  
de la tension à vide des deux machines.  
11. Pour obtenir de plus amples renseignements sur la sûreté, voir  
le code “Code for safety in welding and cutting” CSA Standard  
W 117.2-1974.  
f. Si on utilise la machine à souder comme une source de  
courant pour soudage semi-automatique, ces precautions  
pour le porte-électrode s’applicuent aussi au pistolet de  
soudage.  
PRÉCAUTIONS DE SÛRETÉ POUR  
LES MACHINES À SOUDER À  
TRANSFORMATEUR ET À  
REDRESSEUR  
2. Dans le cas de travail au dessus du niveau du sol, se protéger  
contre les chutes dans le cas ou on recoit un choc. Ne jamais  
enrouler le câble-électrode autour de n’importe quelle partie du  
corps.  
3. Un coup d’arc peut être plus sévère qu’un coup de soliel, donc:  
a. Utiliser un bon masque avec un verre filtrant approprié ainsi  
qu’un verre blanc afin de se protéger les yeux du rayon-  
nement de l’arc et des projections quand on soude ou  
quand on regarde l’arc.  
1. Relier à la terre le chassis du poste conformement au code de  
l’électricité et aux recommendations du fabricant. Le dispositif  
de montage ou la piece à souder doit être branché à une  
bonne mise à la terre.  
b. Porter des vêtements convenables afin de protéger la peau  
de soudeur et des aides contre le rayonnement de l‘arc.  
c. Protéger l’autre personnel travaillant à proximité au  
soudage à l’aide d’écrans appropriés et non-inflammables.  
2. Autant que possible, I’installation et l’entretien du poste seront  
effectués par un électricien qualifié.  
3. Avant de faires des travaux à l’interieur de poste, la debranch-  
er à l’interrupteur à la boite de fusibles.  
4. Des gouttes de laitier en fusion sont émises de l’arc de  
soudage. Se protéger avec des vêtements de protection libres  
de l’huile, tels que les gants en cuir, chemise épaisse, pan-  
talons sans revers, et chaussures montantes.  
4. Garder tous les couvercles et dispositifs de sûreté à leur place.  
5. Toujours porter des lunettes de sécurité dans la zone de  
soudage. Utiliser des lunettes avec écrans lateraux dans les  
zones où l’on pique le laitier.  
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iv  
iv  
MASTER TABLE OF CONTENTS FOR ALL SECTIONS  
RETURN TO MAIN MENU  
Page  
Safety.................................................................................................................................................i-iii  
Installation.............................................................................................................................Section A  
Technical Specifications .............................................................................................................A-2  
Safety Precautions......................................................................................................................A-3  
Select Proper Location ...............................................................................................................A-3  
Stacking ......................................................................................................................................A-3  
Tilting...........................................................................................................................................A-3  
High Frequency Interference Protection.....................................................................................A-3  
Input Electrical Connections.......................................................................................................A-3  
Gas Input Connections...............................................................................................................A-4  
Output Connections....................................................................................................................A-5  
Torch.....................................................................................................................................A-5  
Operation...............................................................................................................................Section B  
Safety Precautions ....................................................................................................................B-2  
Description ................................................................................................................................B-2  
Preheating Temperature .............................................................................................................B-2  
User Responsibilities .................................................................................................................B-3  
Operational Features and Controls ............................................................................................B-3  
Design Features and Advantages ..............................................................................................B-3  
Cutting Capability.......................................................................................................................B-4  
Consumable Life.........................................................................................................................B-4  
Limitations ..................................................................................................................................B-5  
Controls and Settings.................................................................................................................B-5  
Pilot Arc Discussion....................................................................................................................B-6  
Procedure Recommendations....................................................................................................B-7  
General.................................................................................................................................B-7  
Suggestions For Extra Utility From The Pro-Cut System....................................................B-7  
Accessories ..........................................................................................................................Section C  
Maintenance .........................................................................................................................Section D  
Theory of Operation .............................................................................................................Section E  
Troubleshooting and Repair.................................................................................................Section F  
How to Use Troubleshooting Guide............................................................................................F-2  
Troubleshooting Guide................................................................................................................F-4  
Test Procedures ..........................................................................................................................F-9  
Replacement Procedures .........................................................................................................F-29  
Electrical Diagrams..............................................................................................................Section G  
Parts Manual (Pro Cut 25)...............................................................................................P-357 Series  
Cutting Torch...................................................................................................P-210-U  
PRO-CUT 25  
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NOTES  
PRO-CUT 25  
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Section A-1  
Section A-1  
TABLE OF CONTENTS  
- INSTALLATION SECTION -  
Installation  
Technical Specifications .............................................................................................................A-2  
Safety Precautions......................................................................................................................A-3  
Select Proper Location...............................................................................................................A-3  
Stacking......................................................................................................................................A-3  
Tilting ..........................................................................................................................................A-3  
High Frequency Interference Protection.....................................................................................A-3  
Input Electrical Connections.......................................................................................................A-3  
Gas Input Connections...............................................................................................................A-4  
Output Connections ...................................................................................................................A-5  
Torch.....................................................................................................................................A-5  
PRO-CUT 25  
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A-2  
A-2  
INSTALLATION  
TECHNICAL SPECIFICATIONS - PRO-CUT 25 (K1756-1)  
INPUT - SINGLE PHASE / 60 HERTZ ONLY  
Standard Voltage  
1Ø Input Current at Rated Output  
115/230/1/50/60Hz  
115 V : 15 A @ 20%  
115 V : 26.7A@ 60%  
115 V : 37.7A@ 35%  
230 V : 15 A@100%  
230 V : 19 A @ 60%  
RATED OUTPUT  
Duty Cycle  
20% on 115 V  
60% on 115 V  
100% on 230 V  
35% on 115 V  
60% on 230 V  
AMPS  
15 A  
20 A  
20 A  
25 A  
25 A  
OUTPUT  
Current  
Range  
Open Circuit  
Voltage  
Pilot Current  
12-25 Amps  
400 VDC  
12 Amps  
REQUIRED GAS FLOW RATE  
REQUIRED GAS INLET PRESSURE  
55 PSI @ 240 SCFH  
65 to 150 PSI  
( 3.8 Bar. @ 6800 LHR)  
(4.5 Bar. TO 10.3 Bar.)  
RECOMMEND INPUT WIRE AND FUSE SIZES  
For all plasma cutting applications  
Based on U.S. National Electrical Code  
Ambient Temperature 30oC or Less  
Output  
Input Cord  
Plug  
AC Input  
Voltage  
at  
50/60  
Hertz  
Fuse  
Type 75oC  
Copper Wire in Conduit  
AWG (IEC) Sizes  
(Super Lag)  
Circuit Breaker  
(Delay Type)  
Size  
2 Input Supply Wires  
#14 (2.5 mm2)  
1 Ground Wire  
#14 (2.5 mm2)  
25 A 230V-1Ø  
6-20P or 6-30P or 6-50P  
20 AMPS  
#12 (4 mm2)  
#12 (4 mm2)  
#12 (4 mm2)  
#12 (4 mm2)  
#12 (4 mm2)  
#12 (4 mm2)  
15 A  
20 A  
25 A  
115V-1Ø 5-15P* or 5-20P* or 5-30P or 5-50P  
15 AMPS  
20 AMPS  
30 AMPS  
115V-1Ø 5-20P* or 5-30P or 5-50P  
115V-1Ø  
5-30P or 5-50P  
PHYSICAL DIMENSIONS  
Weight  
Height  
Width  
Depth  
Including  
Torch Cable  
35 lbs.  
10.2 in.  
260 mm  
6.3 in.  
16.1 in.  
15.9 kg.  
160 mm  
410 mm  
* Included with machine  
PRO-CUT 25  
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A-3  
A-3  
INSTALLATION  
Read entire Installation Section before installing the  
PRO-CUT 25.  
HIGH FREQUENCY INTERFERENCE  
PROTECTION  
The PRO-CUT 25 employs a touch start mechanism  
for arc initiation which eliminates high frequency emis-  
sions from the machine as compared with spark gap  
and solid state type high frequency generators. Keep  
in mind, though, that these machines may be used in  
an environment where other high frequency generating  
machines are operating. By taking the following steps,  
high frequency interference into the Pro-Cut can be  
minimized  
SAFETY PRECAUTIONS  
WARNING  
ELECTRIC SHOCK CAN KILL.  
Only qualified personnel  
should install this machine.  
Turn the input power OFF  
at the disconnect switch or  
fuse box and discharge input  
capacitors before working  
inside the equipment.  
(1) Make sure the power supply chassis is connected  
to a good earth ground. The work terminal ground  
does NOT ground the machine frame.  
(2) Keep the work clamp isolated from other work  
clamps that have high frequency.  
Do not touch electrically hot parts.  
Turn the PRO-CUT Power Switch OFF  
when connecting power cord to input  
power.  
(3) If the work clamp cannot be isolated, then keep the  
clamp as far as possible from other work clamp  
connections.  
___________________________________________  
(4) When the machine is enclosed in a metal building,  
several good earth driven electrical grounds  
around the periphery of the building are recom-  
mended.  
SELECT PROPER LOCATION  
Place the PRO-CUT 25 where clean cool air can freely  
circulate in and out the side louvers. Dirt, dust or any  
foreign material that can be drawn into the machine  
should be kept at a minimum. Failure to observe these  
precautions can result in excessive operating temper-  
atures and nuisance shutdown of the machine.  
Failure to observe these recommended installation  
procedures may cause improper function of the Pro-  
Cut or possibly even damage to the control system or  
power supply components.  
A source of clean, dry air or nitrogen must be supplied  
to the PRO-CUT 25. Oil in the air is a severe problem  
and must be avoided. The supply pressure must be  
between 80 and 150 psi. The flow rate is approximate-  
ly 4.0 cfm (113 l/min.). Failure to observe these pre-  
cautions could result in excessive operating tempera-  
tures or damage to the torch.  
INPUT ELECTRICAL CONNECTIONS  
The PRO-CUT 25 is rated for 115VAC or 230VAC  
inputs and will automatically reconnect for the supplied  
voltage. The machine is shipped from the factory for  
operation on 115VAC 15 amp circuits. Use on 15 amp  
branch circuits will limit cutting output as indicated by  
the graphics around the output knob. If the output is set  
at 20 amps or greater, the input fuse or circuit breaker  
may “blow” in roughly 30 seconds or less (depending  
on fuse or circuit breaker type).  
STACKING  
The PRO-CUT 25 cannot be stacked.  
To achieve 20 amp output with 115VAC input, replace  
the 15 amp plug on the input cord with the supplied 20  
amp plug, and connect the unit to a 20 amp branch cir-  
cuit with super lag fuses (or equivalent breaker). To  
install the supplied 20 amp plug: Connect the white  
(neutral) wire under terminal clamp with silver screw,  
and black (hot) wire under terminal clamp with brass  
screw. Connect green wire under terminal clamp with  
green screw. Tighten terminal wire clamp screws  
securely.  
TILTING  
The PRO-CUT 25 must be placed on a stable, level  
surface so it will not topple over.  
PRO-CUT 25  
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A-4  
A-4  
INSTALLATION  
GAS INPUT CONNECTIONS  
WARNING  
• Failure to wire as instructed may cause personal  
injury or damage to equipment.  
• To be installed or checked by an electrician or  
qualified person only.  
------------------------------------------------------------------------  
Use of normal 20 amp household breakers may result  
in over current trips. If breaker trips occur, reduce the  
cutting current output until nuisance trips stop.  
Supply the PRO-CUT 25 with clean compressed air or  
nitrogen.  
Supply pressure must be between 80 psi  
and 150 psi.  
Flow rate should be approximately 4.0  
cfm (113 I/min.).  
To achieve the full 25 amp output capability of the  
machine with 115 VAC input, remove the 15 amp or 20  
amp plug on the input cord and install a 30 amp or 50  
amp plug designed for 115 VAC (NEMA style 5-30P or  
5-50P). Follow the instructions included with the plug.  
Connect to an appropriate branch circuit with a mating  
receptacle.  
NOTE: Oil in the air supply to the PRO-CUT 25 can  
cause severe problems. Use only a clean air  
supply.  
Compressed gas can be supplied either through the air  
1
4
fitting supplied with the machine or through the / -19  
BSPP thread at the rear of the machine. To use the air  
fitting supplied with the machine (packaged in the con-  
sumable kit), apply teflon tape to the fitting threads and  
install the fitting in the port at the rear of the machine.  
The PRO-CUT 25 performs best when connected to  
230VAC inputs. To change over to 230VAC operation,  
install a 230VAC plug with a current rating equal to or  
greater than 20 amps.  
• If compressed air is being used, it is highly recom-  
mended that an inline filter be installed in the air sup-  
ply line ahead of the air connection to the PRO-CUT  
25.  
For use on engine drives, keep in mind the above input  
draw restrictions and the following precaution.  
The PRO-CUT 25 can be operated on engine driven  
generators as long as the 230 volt auxiliary meets the  
following conditions:  
• A standard nominal 5 micron inline filter is recom-  
mended; however, for optimum performance,select a  
prefilter with a 3 micron absolute rating. If these filter  
ratings are unavailable, anything with a rating less  
than, or equal to, 20 micron would be acceptable to  
use. In line filter elements will generally filter the air  
with little restriction to the airflow until the element is  
about 75% contaminated. After this point, there will  
be a noticeable pressure drop in the line. Filter ele-  
ments should be replaced when a pressure drop of 8-  
10 psi is indicated; however, for optimum perfor-  
mance of the PRO-CUT 25, the filter element should  
be replaced at or before the pressure drop reaches 8  
psi. Be sure to select a filter that will accommodate  
the necessary flow rating for the PRO-CUT 25 as  
specified in the Installation section of this instruction  
manual under the Gas Input Connections heading.  
• The AC waveform peak voltage is below 400 volts*.  
• The AC waveform frequency is between 45 and 65  
Hz.  
• The RMS voltage of the AC waveform is always  
greater than 208VAC *.  
* for 115 VAC input divide these values in half  
The following Lincoln engine drives meet these condi-  
tions when run in the high idle mode:  
Ranger 200 & 250 engine drives  
Commander 300, 400, & 500 engine drives  
Some engine drives do not meet these conditions (eg  
Miller Bobcats, etc). Operation of the PRO-CUT 25 is  
not recommended on engine drives not conforming to  
these conditions. Such combinations may overvoltage  
the PRO-CUT 25 power source.  
PRO-CUT 25  
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A-5  
A-5  
INSTALLATION  
NOTE: When using nitrogen gas from a cylinder, the  
cylinder must have a pressure regulator.  
Maximum psi from a nitrogen gas cylinder to  
the PRO-CUT 25 regulator should never  
exceed 150 psi.  
Install a hose between the nitrogen gas  
cylinder regulator and the PRO-CUT 25  
gas inlet  
.
WARNING  
CYLINDER could explode if dam-  
aged.  
• Keep cylinder upright and chained  
to a fixed support.  
• Keep cylinder away from areas where it could be  
damaged.  
• Never lift machine with cylinder attached.  
• Never allow the cutting torch to touch the cylinder.  
• Keep cylinder away from live electrical parts.  
• Maximum inlet pressure 150 psi.  
__________________  
OUTPUT CONNECTIONS  
Torch  
The PRO-CUT 25 is sent from the factory with a 15’  
PCT 20 cutting torch installed. Additional cutting torch-  
es can be ordered from the K1615 series. Hand-held  
torches come with 15' or 25’ cables.  
PRO-CUT 25  
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A-6  
A-6  
NOTES  
PRO-CUT 25  
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Section B-1  
Section B-1  
TABLE OF CONTENTS  
- OPERATION SECTION -  
Operation...............................................................................................................................Section B  
Safety Precautions......................................................................................................................B-2  
Description .................................................................................................................................B-2  
Preheating Temperature .............................................................................................................B-2  
User Responsibility ....................................................................................................................B-3  
Operational Features and Controls ............................................................................................B-3  
Design Features and Advantages...............................................................................................B-3  
Cutting Capability .......................................................................................................................B-4  
Consumable Life.........................................................................................................................B-4  
Limitations...................................................................................................................................B-5  
Controls and Settings.................................................................................................................B-5  
Pilot Arc Discussion ...................................................................................................................B-6  
Procedure Recommendations....................................................................................................B-7  
General.................................................................................................................................B-7  
Suggestions for Extra Utility From the Pro-Cut System......................................................B-7  
PRO-CUT 25  
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B-2  
B-2  
OPERATION  
Read and understand this entire section before operat-  
ing the machine.  
DESCRIPTION  
The PRO-CUT 25 is a constant current, continuous  
control plasma cutting power source. It provides supe-  
rior and reliable starting characteristics, cutting visibili-  
ty and arc stability. The control system has a safety  
mechanism to insure that the nozzle and electrode are  
in place before cutting or gouging. This is extremely  
important due to the high voltages involved.  
SAFETY PRECAUTIONS  
WARNING  
ELECTRIC SHOCK  
can kill.  
• Do not touch electrically live parts  
or electrode with skin or wet  
clothing.  
The PRO-CUT 25 comes standard with an air regula-  
tor and pressure gauge. The machine also comes with  
an input power cord. Hand-held torches are available  
in 15' or 25' cable. Consumables are included with  
each Pro-Cut purchase so that cutting can begin right  
out of the box. Consumables can also be ordered as  
individual packages.  
• Insulate yourself from work and  
ground.  
• Always wear dry insulating  
gloves.  
The PRO-CUT 25 initiates the plasma arc with a sim-  
ple, yet reliable, touch start mechanism. This system  
eliminates many of the failure problems associated  
with hi-frequency start systems.  
FUMES AND GASES  
can be dangerous.  
• Keep your head out of fumes.  
• Use ventilation or exhaust to  
remove fumes from breathing  
zone.  
PREHEAT TEMPERATURE FOR  
PLASMA CUTTING  
WELDING, CUTTING and  
GOUGING SPARKS  
Preheat temperature control is not necessary in most  
applications when plasma arc cutting or gouging.  
Preheat temperature control may be necessary on high  
carbon alloy steels and heat treated aluminum for crack  
resistance and hardness control. Job conditions, pre-  
vailing codes, alloy level, and other considerations may  
also require preheat temperature control. The following  
minimum preheat temperature is recommended as a  
starting point. Higher temperatures may be used as  
required by the job conditions and/or prevailing codes. If  
cracking or excessive hardness occurs on the cut face,  
higher preheat temperature may be required. The rec-  
ommended minimum preheat temperature for plate  
thickness up to 1/2" (12.7mm) is 70°F (21.1°C).  
can cause fire or explosion  
• Keep flammable material away.  
• Do not weld, cut or gouge on  
containers that have held combustibles.  
ARC RAYS  
can burn.  
• Wear eye, ear and body  
protection.  
PLASMA ARC  
can injure  
• Keep your body away from nozzle  
and plasma arc.  
• Operate the pilot arc with caution. The  
pilot arc is capable of burning the  
operator, others or even piercing  
safety clothing.  
Observe additional Safety Guidelines detailed in  
the beginning of this manual.  
PRO-CUT 25  
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B-3  
B-3  
OPERATION  
- Continuous control, 12 - 25 amps.  
USER RESPONSIBILITY  
- Reliable touch start mechanism for plasma arc initia-  
tion.  
Because design, fabrication, erection and cutting vari-  
ables affect the results obtained in applying this type of  
information, the serviceability of a product or structure  
is the responsibility of the user. Variation such as plate  
chemistry, plate surface condition (oil, scale), plate  
thickness, preheat, quench, gas type, gas flowrate  
and equipment may produce results different than  
those expected. Some adjustments to procedures may  
be necessary to compensate for unique individual con-  
ditions. Test all procedures duplicating actual field con-  
ditions.  
- Rapid arc restrike for fast cutting of expanded metal.  
- Input over voltage protection.  
- Bright 3.0 second timed pilot arc.  
- Purge momentary push button.  
- Air regulator and pressure gage included.  
- Parts-in-Place mechanism to detect proper installa-  
tion of consumables and torch.  
OPERATIONAL FEATURES AND  
CONTROLS  
- Latching Parts-in-Place mechanism. Requires the  
operator to turn the machine off and then on to reset.  
The PRO-CUT 25 comes with an ON/OFF POWER  
SWITCH, OUTPUT CURRENT CONTROL, and  
PURGE BUTTON.  
- Preflow/Postflow timing. Preflow is eliminated if arc  
is re-initiated in Postflow.  
DESIGN FEATURES AND  
ADVANTAGES  
- Thermostatic Protection.  
- Solid state over-current protection.  
- Automatic reconnect for 115 VAC or 230 VAC inputs.  
- Dead front display for machine status.  
The PRO-CUT 25 design makes plasma cutting  
uncomplicated. This list of design features and advan-  
tages will help you understand the machine's total  
capabilities so that you can get maximum use from  
your machine.  
- Unique electrode and Vortech™ nozzle design for  
optimum cooling and long life.  
- Light weight and portable design for industrial use.  
- Swirl texture inside Vortech™ nozzle for better start-  
ing reliability and higher quality cuts.  
PRO-CUT 25  
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B-4  
B-4  
OPERATION  
CUTTING CAPABILITY  
The PRO-CUT 25 is rated at 25 amps, at 35% duty cycle on a 10 minute basis. If the duty cycle is exceeded, a  
thermal protector will shut off the output of the machine until it cools to the normal operating temperature.  
Figure B.1 shows the cut capacity of the PRO-CUT 25 when cutting mild steel. (The graph plots cut thickness vs.  
torch travel speed with a torch standoff of 0.15".)  
Lincoln's PRO-CUT 25  
Cut Capacity Chart  
80  
60  
40  
20  
0
0.125  
0.375  
0.250  
Metal Thickness (Inches)  
Figure B.1  
CONSUMABLE LIFE  
The expected life for the PRO-CUT 25's electrode under normal operating conditions is approximately 1000  
starts/cuts. An erosion of .060" is typical for end of electrode life, however, the electrode life may last longer. A  
green and erratic arc will indicate definite electrode failure and the electrode should be replaced immediately.  
It is recommended that consumables be replaced in complete sets. (Example: Electrode and Nozzle). This will  
maximize the performance of the PRO-CUT 25 system.  
PRO-CUT 25  
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B-5  
B-5  
OPERATION  
• Push-in and hold the Purge button to check or set  
the gas pressure. Pull the pressure regulator cap out  
and turn it to set the pressure.  
LIMITATIONS  
Do not exceed output current and duty cycle rating of  
machine. Do not use the PRO-CUT 25 for pipe thaw-  
ing.  
- Adjust the gas regulator for 65 PSI for 15’ or 25’  
torches.  
- Release the Purge button.  
- The gas will immediately turn off. The pressure  
gage may show an increase in pressure after the  
air turns off but this is normal. Do NOT reset the  
pressure while the air is NOT flowing.  
CONTROLS AND SETTINGS  
PRESSURE REGULATOR  
CAP  
• When ready to cut, place the torch near the work,  
make certain all safety precautions have been taken  
and pull the trigger.  
- The air will flow for a preflow time of 2 seconds  
and the pilot arc will start. (Exceptions: the first  
time that the trigger is pulled after the machine is  
turned on, or after a thermal tripout, will be  
ignored. This is a safety feature to prevent the  
pilot arc from firing unexpectedly or if the torch  
button is pressed because it is laying up against  
something. The other exception is if the machine  
is in postflow, then the preflow time is skipped  
and the pilot arc will start immediately.)  
- The pilot arc will run for 3.0 seconds and shut off  
unless the arc is brought in contact with the work  
and the arc is transferred. Avoid excessive pilot  
arc time by transferring the arc to the workpiece  
quickly.  
- When the arc is brought within 1/8” - 1/4" from  
the work piece: the arc will transfer, the current  
will ramp to the setting on the control panel, and  
the cut can last indefinitely (or until the duty  
cycle of the Pro-Cut is exceeded).  
When preparing to cut, position the machine as close  
to the work as possible. Make sure you have all mate-  
rials needed to complete the job and have taken all  
safety precautions. It is important to follow these oper-  
ating steps each time you use the machine.  
• Pierce the work piece by slowly lowering the torch  
onto the metal at a 300 angle away from the operator.  
This will blow the dross away from the torch tip.  
Slowly rotate the torch to vertical position as the arc  
becomes deeper.  
• Turn the machine's ON/OFF POWER SWITCH to  
OFF position.  
• Connect the air supply to the machine.  
TORCH AT 300 ANGLE  
TO PIERCE  
• Turn the main power and the machine power switch  
on.  
- The fan should start.  
ROTATE TO  
- The pre-charge circuit will operate for 3 seconds,  
then the green "Power" LED should turn on.  
900 ANGLE TO CUT  
300  
• Be sure that the work lead is clamped to the work-  
piece before cutting.  
900  
VERTICAL ANGLE  
FOR CUTTING  
• Set the output current control knob at maximum1  
position for higher cutting speed and less dross for-  
mation. Reduce the current, if desired to reduce the  
kerf (cut) width, heat affected zone or travel speed  
as required.  
CUT  
• Keep moving while cutting. Cut at a steady speed  
without pausing. Maintain the cutting speed so that  
the arc leg is 10° to 20° behind the travel direction.  
1
Maximum output requires a 30 amp input circuit and breaker. Refer to the  
Technical Specifications for proper input circuit guidelines.  
PRO-CUT 25  
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B-6  
B-6  
OPERATION  
• After the problem is found, or if there is nothing  
apparently wrong, reset the machine by turning the  
power switch OFF and then ON again. (It is possi-  
ble for electrical noise to trip the safety circuit on rare  
occasions. This should not be a regular occurrence.)  
5° - 15° Leading Angle  
• If the machine does not reset or continues to trip,  
Direction of Travel  
WARNING  
ELECTRIC SHOCK CAN KILL.  
• Turn off machine at the disconnect  
switch on the front of the machine  
before tightening, cleaning or replacing  
10° - 20°  
Arc Lag  
consumables.  
----------------------------------------------------------------------------  
Use a 5° - 15° leading angle in the direction of the cut.  
• Finish the cut to be made and release the trigger.  
• When the trigger is released, the arc will stop.  
consult the Troubleshooting Section.  
• Use the proper cutting procedures referred to in  
Procedure Recommendations.  
- The gas will continue to flow for 10 seconds of  
postflow. If the trigger is activated within this time  
period, the pilot arc will immediately restart.  
PILOT ARC DISCUSSION  
• If the dross is difficult to remove, reduce the cutting  
speed. High speed dross is more difficult to remove  
than low speed dross.  
The PRO-CUT has a smooth, continuous pilot arc.  
The pilot arc is only a means of transferring the arc to  
the workpiece for cutting. Repeated pilot arc starts, in  
rapid succession, is not recommended as these starts  
will generally reduce consumable life. Occasionally,  
the pilot arc may sputter or start intermittently. This is  
aggravated when the consumables are worn or the air  
pressure is too high. Always keep in mind that the pilot  
arc is designed to transfer the arc to the workpiece and  
not for numerous starts without cutting.  
• The right side of the cut is more square than the left  
as viewed along the direction of travel.  
• Clean spatter and scale from the nozzle frequently.  
• If the "SAFETY" LED lights at any time; check the  
following:  
When the pilot arc is started, a slight impulse will be felt  
in the torch handle. This occurrence is normal and is  
the mechanism which starts the plasma arc. This  
impulse can also be used to help troubleshoot a "no  
start" condition.  
• Check the assembly of the torch consumables. If  
they are not properly in place, the machine will not  
start. Make sure that the shield cup is hand  
tight. Do not use pliers or over tighten.  
• Check the conditions of the inside of the nozzle. If  
debris has collected, rub the electrode on the  
inside bottom of the nozzle to remove any oxide  
layer that may have built up. Refer to  
"Suggestions for Extra Utility from the PRO-CUT  
system".  
• Check the condition of the electrode. If the end  
has a crater-like appearance, replace it along with  
the nozzle. The maximum wear depth of the elec-  
trode is approximately .062”. A green and erratic  
arc will indicate definite electrode failure and the  
electrode should be replaced immediately.  
• Replace the nozzle when the orifice exit is eroded  
away or oval shaped.  
PRO-CUT 25  
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B-7  
B-7  
OPERATION  
1. Occasionally an oxide layer may form over the tip of  
the electrode, creating an insulating barrier  
between the electrode and nozzle. This will result in  
the tripping of the Pro-Cut's safety circuit. When  
this happens turn the power off, remove the nozzle  
and electrode and use the electrode to rub against  
the inside bottom surface of the nozzle. This will  
help remove any oxide buildup. Replace the noz-  
zle, turn on the power and continue cutting. If the  
safety circuit continues to trip after cleaning the  
consumables, then replace them with a new set.  
Do not continue to try and cut with excessively worn  
consumables as this can cause damage to the  
torch head and will degrade cut quality. Do not  
allow torch cable or body to contact hot surface.  
PROCEDURE RECOMMENDATIONS  
When properly used, plasma arc cutting is a very eco-  
nomical process. Improper use will result in a very high  
operating cost.  
General - In All Cases  
• Follow safety precautions as printed throughout  
this operating manual and on the machine.  
• If piercing is required, slowly lower the torch at  
an angle of about 30° to blow the dross away  
from the torch tip and slowly rotate the torch to  
a vertical position as the arc becomes deeper.  
This process will blow a lot of molten metal and  
dross. Be careful! Blow the dross away from  
the torch, the operator and any flammable  
objects.  
2. To improve consumable life, here are some sug-  
gestions that may be useful:  
a. Make sure the air supply to the Pro-Cut is  
clean and free of oil. Use several extra in line  
filters if necessary.  
• The nozzle may be dragged on the metal sur-  
face, touching it lightly to the surface. NOTE:  
The use of a drag cup with the PRO-CUT is  
not recommended. The increased standoff  
distance reduces the overall performance of  
the PRO-CUT.  
b. Minimize dross buildup on the nozzle tip by  
starting the cut from the edge of the plate when  
possible.  
c. Pierce cutting should be done only when nec-  
essary. If piercing, angle torch about 30° from  
the plane perpendicular to the work piece,  
transfer the arc, then bring the torch perpen-  
dicular to the work and begin parallel move-  
ment.  
Torch Standoff  
d. Reduce the number of pilot arc starts without  
transferring to the work.  
DRAG thru 1/16”  
e. Reduce the pilot arc time before transferring to  
the work.  
Standoff  
• Where possible, start the cut from the edge of  
the work piece.  
f. Set air pressure to recommended setting. A  
higher or lower pressure will cause turbulence  
in the plasma arc, eroding the orifice of the  
nozzle tip.  
• Keep moving! A steady speed is necessary. Do  
not pause.  
g. Use only Lincoln consumable parts. These  
parts are patented and using any other  
replacement consumables may cause damage  
to the torch or reduce cut quality.  
Suggestions for Extra Utility from the  
PRO-CUT System:  
WARNING  
ELECTRIC SHOCK CAN KILL.  
• Turn off machine at the disconnect  
switch on the front of the machine  
before tightening, cleaning or replacing  
consumables.  
----------------------------------------------------------------------------  
PRO-CUT 25  
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B-8  
B-8  
NOTES  
PRO-CUT 25  
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Section C-1  
Section C-1  
TABLE OF CONTENTS  
- ACCESSORIES -  
Accessories...........................................................................................................................Section C  
Options/Accessories...................................................................................................................C-2  
PRO-CUT 25  
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C-2  
C-2  
ACCESSORIES  
ALWAYS USE GENUINE LINCOLN GENERAL OPTIONS /  
ELECTRIC ELECTRODES AND ACCESSORIES  
VORTECH™ NOZZLES  
The following options/accessories are available for  
your PRO-CUT 25 from your local Lincoln Distributor.  
• Only Genuine Lincoln Electric consumables yield the  
best cutting performance for the PRO-CUT 25.  
S22147-028 - VORTECH™ nozzle with an .028” (0.7  
mm) Orifice  
The patented VORTECH™ nozzle provides an  
extra “kick” of swirl as the arc exits the nozzle which  
improves cutting performance. No other nozzle has  
S22149 - Electrode - replacement electrodes for cut-  
ting.  
this capability or can match its performance.  
S22150 - Shield Cup - This shields the nozzle and pro-  
vides more visibility to the workpiece. Note the shield  
cup does not prevent the torch tip from touching the  
workpiece.  
K1615 Series - PCT 20 Torches come in 15’ and 25’  
lengths. Refer to the Parts Pages in the rear of this  
manual for Torch parts.  
PRO-CUT 25  
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Section D-1  
Section D-1  
TABLE OF CONTENTS  
-MAINTENANCE-  
Maintenance .........................................................................................................................Section D  
Routine Maintenance..................................................................................................................D-2  
Periodic Maintenance.................................................................................................................D-2  
Thermal Protection .....................................................................................................................D-2  
Replacement Of Internal Fuse....................................................................................................D-2  
Major Component Locations .....................................................................................................D-3  
PRO-CUT 25  
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D-2  
D-2  
MAINTENANCE  
PERIODIC MAINTENANCE  
WARNING  
ELECTRIC SHOCK can kill.  
• Have an electrician install and service  
this equipment.  
• Turn the input power off at the fuse box  
before working on equipment.  
• Do not touch electrically hot parts.  
• Prior to Performing preventative main-  
tenance, perform the following capaci-  
tor discharge procedure to avoid elec-  
tric shock.  
WARNING  
ELECTRIC SHOCK CAN KILL.  
• Turn off machine at the disconnect  
switch on the front of the machine  
before tightening, cleaning or replacing  
consumables.  
----------------------------------------------------------------------------  
Change consumables as required.  
THERMAL PROTECTION  
---------------------------------------------------------------------  
Thermal Detection Devices protect the machine from  
excessive operating temperatures. Excessive temper-  
atures may be caused by a lack of cooling air or oper-  
ating the machine beyond the duty cycle and output  
rating. If excessive operating temperatures should  
occur, the yellow thermal LED will light and the  
Detection Devices will prevent output voltage or cur-  
rent.  
ROUTINE MAINTENANCE  
1. Keep the cutting or gouging area and the area  
around the machine clean and free of combustible  
materials. No debris should be allowed to collect  
which could obstruct air flow to the machine.  
2. Every 6 months or so, the machine should be  
cleaned with a low pressure airstream. Keeping the  
machine clean will result in cooler operation and  
higher reliability. Be sure to clean these areas:  
These Detection Devices are self-resetting once the  
machine cools sufficiently. If the thermostat shutdown  
was caused by excessive output or duty cycle and the  
fan is operating normally, the Power Switch may be left  
on and the reset should occur within a 15 minute peri-  
od. If the fan is not turning or the air intake louvers  
were obstructed, then the power must be switched off  
and the fan problem or air obstruction must be correct-  
ed.  
- Printed circuit boards and heat sinks  
- Power switch  
CAUTION  
• When using a low pressure aistream, wear  
appropiate eye protection.  
A protection circuit is included to monitor the voltage  
across filter capacitors. In the event that the capacitor  
voltage is too high, the protection circuit will prevent  
output.  
------------------------------------------------------------------------  
3. Examine the sheet metal case for dents or break-  
age. Repair the case as required. Keep the case in  
good condition to insure that high voltage parts are  
protected and correct spacings are maintained. All  
external sheet metal screws must be in place to  
insure case strength and electrical ground continu-  
ity.  
REPLACEMENT OF INTERNAL FUSES  
The PRO-CUT 25 has additional protection provided to  
some circuits through internal fuses. For replacement  
of those fuses proceed as follows:  
4. Inspect the cable periodically for any slits or punc-  
ture marks in the cable jacket. Replace if neces-  
sary. Check to make sure that nothing is crushing  
the cable and blocking the flow of air through the air  
tube inside. Also, check for kinks in the cable peri-  
odically and relieve any so as not to restrict the flow  
of air to the torch.  
1. Turn off the power to the unit and remove the input  
plug.  
2. Allow the machine to stand for 5 minutes to let the  
input capacitors discharge.  
3. Remove the machine cover.  
4. Replace the blown fuse with a new 0.5A 500V  
slowblow fuse or 32A 400V fuse as appropriate.  
NOTE: If the fuse blows again after power is restored,  
the cause could be an internal breakdown in  
the power unit. In this case, take the unit to an  
authorized Lincoln Field Service Shop.  
PRO-CUT 25  
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D-3  
D-3  
MAINTENANCE  
FIGURE D.2 – MAJOR COMPONENT LOCATIONS  
1. Central Metal Wall  
2. Main Board  
3. Input Board  
4. Control Board  
5. Fan  
6. Case Wraparound  
7. Torch  
6
4
5
3
1
O
POWER  
N
GAS PRESSURE  
THERMAL  
SAFETY  
!
O
P
U
R
G
E
F
F
20  
L
IN  
C
E
O
L
L
E
N
C
T
R
IC  
25  
R
R
EQ  
EQ  
U
IR  
IR  
ES  
E
U
20  
30  
A/  
A/  
PR  
O-CUT 25  
1
1
S
5V  
5V  
BR  
1
1
AN  
AN  
C
BR  
H
H
C
C
IR  
IR  
C
C
C
UIT  
U
IT  
7
0
2
T
C
P
2
PRO-CUT 25  
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D-4  
D-4  
NOTES  
PRO-CUT 25  
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Section E-1  
Section E-1  
TABLE OF CONTENTS  
-THEORY OF OPERATION SECTION-  
Theory of Operation .............................................................................................................Section E  
General Description ....................................................................................................................E-2  
Input Line Voltage and Auxiliary Transformer .............................................................................E-2  
Precharge and Protection ...........................................................................................................E-3  
Main Transformer ........................................................................................................................E-4  
Output Section and Torch...........................................................................................................E-5  
Control Board .............................................................................................................................E-6  
Protection Circuits ......................................................................................................................E-7  
Overload Protection..............................................................................................................E-7  
Thermal Protection ...............................................................................................................E-7  
Accidental Operation Protection.................................................................................................E-7  
Safety Parts-In-Place Protection ................................................................................................E-7  
Insulated Gate Bipolar Transistor (IGBT) Operation ...................................................................E-8  
FIGURE E.1 – PRO-CUT 25 BLOCK LOGIC DIAGRAM  
WORK CLAMP  
Q1a,b,c  
IRG4BC30W  
Lout  
D10  
BS1  
WRK  
C26  
240uH  
8A  
AC  
SW1  
RL2  
RL2  
RL2  
AC  
L1  
RL3  
A
B
T2  
+12VDC TRANSFER  
PRI  
SEC  
D11  
300uH  
R1  
+
CP  
CP  
CP  
CP  
R1  
CP  
CP  
10/10W  
C1a,b  
RL1  
NZL (2)  
C12  
+
R2  
AC  
AC  
C14  
C2a,b  
R24  
RL1  
RL2  
6.8k/5W  
V1  
V2  
Q2a,b,c  
IRG4BC30W  
115VAC  
L1  
SHUNT  
EL (3)  
T1  
C13  
SH+  
SH-  
230V  
115V  
RL1  
PT  
CN1  
CN2  
9
10  
5
6
3
22  
2
CN3  
15VAC  
15VAC  
1
2
3
4
1
2
3
4
5
6
7
8
SAFETY  
+28VDC  
SEC GND  
OVLOAD  
115/230  
+12VDC  
L1  
12VDC  
Main Inverter Board  
Solenoid 2  
Input  
20  
CN1  
Voltage Board  
15 16  
12 18 14  
1
11  
4
13  
7
19 24 21 23  
8
17  
1
2
3
4
8
6
17  
9
3
1
2
18 14  
7
15  
4
11  
5
16 10 12 13  
23 22 24  
CN1  
12VDC  
Display LED's  
Air  
Solenoid  
1
Purge  
Switch  
Output Control  
Control Board  
PRO-CUT 25  
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E-2  
E-2  
THEORY OF OPERATION  
FIGURE E.2 – INPUT LINE VOLTAGE  
WORK CLAMP  
Q1a,b,c  
IRG4BC30W  
Lout  
D10  
BS1  
WRK  
C26  
240uH  
8A  
AC  
SW1  
RL2  
RL2  
RL2  
AC  
L1  
RL3  
A
B
T2  
+12VDC TRANSFER  
PRI  
+
SEC  
D11  
300uH  
R1  
CP  
CP  
CP  
CP  
R1  
CP  
CP  
10/10W  
C1a,b  
RL1  
NZL (2)  
C12  
+
R2  
AC  
AC  
C14  
C2a,b  
R24  
RL1  
RL2  
6.8k/5W  
V1  
V2  
Q2a,b,c  
IRG4BC30W  
115VAC  
L1  
SHUNT  
EL (3)  
T1  
C13  
SH+  
SH-  
230V  
115V  
RL1  
PT  
CN1  
CN2  
9
10  
5
6
3
22  
2
CN3  
15VAC  
15VAC  
1
2
3
4
1
2
3
4
5
6
7
8
SAFETY  
+28VDC  
SEC GND  
OVLOAD  
115/230  
+12VDC  
L1  
12VDC  
Main Inverter Board  
Solenoid 2  
Input  
20  
CN1  
Voltage Board  
15 16  
12 18 14  
1
11  
4
13  
7
19 24 21 23  
8
17  
1
2
3
4
8
6
17  
9
3
1
2
18 14  
7
15  
4
11  
5
16 10 12 13  
23 22 24  
CN1  
12VDC  
Display LED's  
Air  
Solenoid  
1
Purge  
Switch  
Output Control  
Control Board  
GENERAL DESCRIPTION  
INPUT LINE VOLTAGE, AND  
AUXILIARY TRANSFORMER  
The PRO-CUT 25 is an inverter based constant  
current, continuous control plasma cutting power  
source. The control system has a safety mechanism  
to insure that the nozzle and electrode are in place  
before cutting or gouging. The PRO-CUT 25 initiates  
the plasma arc with a simple, yet reliable, touch start  
mechanism. This system eliminates many of the prob-  
lems associated with hi-frequency type start systems.  
The single-phase input power of 115 230 Volts AC is  
connected to the machine, via an input cord, to a  
switch located on the front panel.  
The PRO-CUT 25 Input voltage board automatically  
reconnects the auxiliary and inverter connections to  
configure the machine for either a low 115V AC or high  
230V AC input voltage. The auxiliary transformer  
develops the appropriate AC voltages to operate the  
cooling fan, the control board, and the inverter board.  
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.  
PRO-CUT 25  
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E-3  
E-3  
THEORY OF OPERATION  
FIGURE E.3 – PRECHARGE AND PROTECTION  
WORK CLAMP  
Q1a,b,c  
IRG4BC30W  
Lout  
D10  
BS1  
WRK  
C26  
240uH  
8A  
AC  
SW1  
RL2  
RL2  
RL2  
AC  
L1  
RL3  
A
B
T2  
+12VDC TRANSFER  
PRI  
C12  
SEC  
D11  
300uH  
R1  
+
CP  
CP  
CP  
CP  
R1  
CP  
CP  
10/10W  
C1a,b  
RL1  
NZL (2)  
+
R2  
AC  
AC  
C14  
C2a,b  
R24  
RL1  
RL2  
6.8k/5W  
V1  
V2  
Q2a,b,c  
IRG4BC30W  
115VAC  
L1  
SHUNT  
EL (3)  
T1  
C13  
SH+  
SH-  
230V  
115V  
RL1  
PT  
CN1  
CN2  
9
10  
5
6
3
22  
2
CN3  
15VAC  
15VAC  
1
2
3
4
1
2
3
4
5
6
7
8
SAFETY  
+28VDC  
SEC GND  
OVLOAD  
115/230  
+12VDC  
L1  
12VDC  
Main Inverter Board  
Solenoid 2  
Input  
20  
CN1  
Voltage Board  
15 16  
12 18 14  
1
11  
4
13  
7
19 24 21 23  
8
17  
1
2
3
4
8
6
17  
9
3
1
2
18 14  
7
15  
4
11  
5
16 10 12 13  
23 22 24  
CN1  
12VDC  
Display LED's  
Air  
Solenoid  
1
Purge  
Switch  
Output Control  
Control Board  
PRECHARGE AND PROTECTION  
The input voltage is rectified by the input rectifier on  
the inverter board. The resultant DC voltage is applied  
to the filter capacitors through the automatic  
reconnect of the input board. The input board also  
contains precharging circuitry for the safe charging of  
the input filter capacitors. Once the capacitors are  
precharged the input board activates the RL3 input  
relay. This connects full input power to the filter  
capacitors. When the filter capacitors are fully  
charged they act as power supplies for the IGBT  
switching circuit. The IGBTs supply the main trans-  
former primary winding with DC current flow.  
The inverter board also monitors the filter capacitors  
for overvoltage. If this occurs, the appropriate signal  
is sent to the control board to disable the machines  
output and to turn on the Thermal/Voltage Overload  
status LED. See IGBT Operation discussion and  
diagrams in this section.  
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.  
PRO-CUT 25  
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E-4  
E-4  
THEORY OF OPERATION  
FIGURE E.4 – MAIN TRANSFORMER  
WORK CLAMP  
Q1a,b,c  
IRG4BC30W  
Lout  
D10  
BS1  
WRK  
C26  
240uH  
8A  
AC  
SW1  
RL2  
RL2  
RL2  
AC  
L1  
RL3  
A
B
T2  
+12VDC TRANSFER  
PRI  
+
SEC  
D11  
300uH  
R1  
CP  
CP  
CP  
CP  
R1  
CP  
CP  
10/10W  
C1a,b  
RL1  
NZL (2)  
C12  
+
R2  
AC  
AC  
C14  
C2a,b  
R24  
RL1  
RL2  
6.8k/5W  
V1  
V2  
Q2a,b,c  
IRG4BC30W  
115VAC  
L1  
SHUNT  
EL (3)  
T1  
C13  
SH+  
SH-  
230V  
115V  
RL1  
PT  
CN1  
CN2  
9
10  
5
6
3
22  
2
CN3  
15VAC  
15VAC  
1
2
3
4
1
2
3
4
5
6
7
8
SAFETY  
+28VDC  
SEC GND  
OVLOAD  
115/230  
+12VDC  
L1  
12VDC  
Main Inverter Board  
Solenoid 2  
Input  
20  
CN1  
Voltage Board  
15 16  
12 18 14  
1
11  
4
13  
7
19 24 21 23  
8
17  
1
2
3
4
8
6
17  
9
3
1
2
18 14  
7
15  
4
11  
5
16 10 12 13  
23 22 24  
CN1  
12VDC  
Display LED's  
Air  
Solenoid  
1
Purge  
Switch  
Output Control  
Control Board  
MAIN TRANSFORMER  
The pair of IGBTs act as a switch assembly. This  
assembly feeds a primary winding of the main trans-  
former. When current is pulsed through this primary  
winding, a resultant current is produced on the sec-  
ondary winding of the main transformer. The DC cur-  
rent flow through the primary winding is redirected or  
“clamped” back to the filter capacitors when the IGBTs  
are turned off. This is needed due to the inductance of  
the transformer primary winding.  
The secondary portion of the main transformer is made  
up of one winding. This winding supplies the  
electrode-to-nozzle and electrode-to-work voltages  
and the resulting currents. This high current winding is  
capable of supplying maximum output current during  
the cutting process. The output current is regulated  
via pulse width modulation. The control circuitry, on  
the inverter board, receives a signal from the control  
board and regulates the output current to the desired  
level.  
The primary current also passes through the current  
transformer, which sends a signal to the control cir-  
cuits of the inverter board. This signal and the control  
circuits limit the maximum primary current flow  
through the IGBTs. The pair of IGBT’s are fired at 15  
microsecond intervals, creating a constant 66.6KHz  
output.  
PRO-CUT 25  
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E-5  
E-5  
THEORY OF OPERATION  
FIGURE E.5 – PLASMA OUTPUT SECTION AND TORCH  
WORK CLAMP  
Q1a,b,c  
IRG4BC30W  
Lout  
240uH  
D10  
BS1  
WRK  
C26  
8A  
AC  
SW1  
RL2  
RL2  
RL2  
AC  
L1  
RL3  
A
B
T2  
+12VDC TRANSFER  
PRI  
SEC  
D11  
300uH  
R1  
+
CP  
CP  
CP  
CP  
R1  
CP  
CP  
10/10W  
C1a,b  
RL1  
NZL (2)  
C12  
+
R2  
AC  
AC  
C14  
C2a,b  
R24  
RL1  
RL2  
6.8k/5W  
V1  
V2  
Q2a,b,c  
IRG4BC30W  
115VAC  
L1  
SHUNT  
SH+  
EL (3)  
T1  
C13  
SH-  
230V  
115V  
RL1  
PT  
CN1  
CN2  
9
10  
5
6
3
22  
2
CN3  
15VAC  
15VAC  
1
2
3
4
1
2
3
4
5
6
7
8
SAFETY  
+28VDC  
SEC GND  
OVLOAD  
115/230  
+12VDC  
L1  
12VDC  
Main Inverter Board  
Solenoid 2  
Input  
20  
CN1  
Voltage Board  
15 16  
12 18 14  
1
11  
4
13  
7
19 24 21 23  
8
17  
1
2
3
4
8
6
17  
9
3
1
2
18 14  
7
15  
4
11  
5
16 10 12 13  
23 22 24  
CN1  
12VDC  
Display LED's  
Air  
Solenoid  
1
Purge  
Switch  
Output Control  
Control Board  
OUTPUT SECTION AND TORCH  
between the electrode and nozzle for maximum elec-  
trode cooling. A portion of the cooling air exits in the  
chamber through vents in the side of the nozzle. A  
swirl texture located inside the bottom of the nozzle  
increases the plenum air swirl strength, and improves  
arc start reliability and parts-in-place verification.  
The output section contains a relay which, upon  
receiving a pilot signal from the control board will  
enable the operation of a pilot arc or a cutting arc. The  
printed circuit board mounted current sensor regulates  
the pilot and cutting current. The output choke, which  
is in series with both the pilot circuit and the cutting  
circuit, provides current filtering to enhance arc stabil-  
ity.  
Plasma arc initiation occurs as follows: First, in the idle  
state, a spring inside the torch head pushes the piston  
and electrode forward to make continuity with the noz-  
zle. When the trigger is pulled, air flow begins and cre-  
ates enough back force on the electrode to overcome  
the force of the spring. However, the solenoid valve  
allows enough forward force on the piston to maintain  
continuity between the consumables. After this  
continuity has been verified, output current is estab-  
lished and regulated. Once the current stabilizes, the  
solenoid valve turns off, removing the forward force on  
the piston. The back pressure drives the piston and  
electrode away from the nozzle, creating the plasma  
arc. The air stream forces the arc out the orifice of the  
nozzle. This appears as a pilot arc, which can then be  
transferred for cutting.  
The PCT 20 torch uses a patented touch start mecha-  
nism that provides superior starting performance over  
other touch start systems. The torch head consists of  
3 major parts: torch body, insulator and piston. The  
insulator provides an electrical barrier between the  
piston and torch body. The piston provides a path for  
electrical current to the electrode. The piston also dri-  
ves the electrode to the nozzle for arc initiation. The  
torch body contains the main torch components: the  
trigger, pilot arc, cutting arc, and air flow systems are  
included. See Figure F.10 & G Section for more detail.  
A copper nozzle with a patented internal swirl is used  
to focus the arc. A small, precise hole in the end of the  
nozzle constricts the arc and increases the current  
density. As the air enters the torch head, it is directed  
PRO-CUT 25  
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E-6  
E-6  
THEORY OF OPERATION  
FIGURE E.6 – CONTROL BOARD  
WORK CLAMP  
Q1a,b,c  
IRG4BC30W  
Lout  
D10  
BS1  
WRK  
C26  
240uH  
8A  
AC  
SW1  
RL2  
RL2  
RL2  
AC  
L1  
RL3  
A
B
T2  
+12VDC TRANSFER  
PRI  
+
SEC  
D11  
300uH  
R1  
CP  
CP  
CP  
CP  
R1  
CP  
CP  
10/10W  
C1a,b  
RL1  
NZL (2)  
C12  
+
R2  
AC  
AC  
C14  
C2a,b  
R24  
RL1  
RL2  
6.8k/5W  
V1  
V2  
Q2a,b,c  
IRG4BC30W  
115VAC  
L1  
SHUNT  
EL (3)  
T1  
C13  
SH+  
SH-  
230V  
115V  
RL1  
PT  
CN1  
CN2  
9
10  
5
6
3
22  
2
CN3  
15VAC  
15VAC  
1
2
3
4
1
2
3
4
5
6
7
8
SAFETY  
+28VDC  
SEC GND  
OVLOAD  
115/230  
+12VDC  
L1  
12VDC  
Main Inverter Board  
Solenoid 2  
Input  
20  
CN1  
Voltage Board  
15 16  
12 18 14  
1
11  
4
13  
7
19 24 21 23  
8
17  
1
2
3
4
8
6
17  
9
3
1
2
18 14  
7
15  
4
11  
5
16 10 12 13  
23 22 24  
CN1  
12VDC  
Display LED's  
Air  
Solenoid  
1
Purge  
Switch  
Output Control  
Control Board  
CONTROL BOARD  
The control board receives status and analog  
feedback signals from the inverter board, input board,  
and various sensors. The control circuitry interprets  
these signals, makes decisions and changes the  
machines mode and output to satisfy the requirements  
as defined by the circuitry. The control board sends a  
signal to the inverter board to control the output  
current but the actual regulation circuits are on the  
inverter board.  
The display board, directly connected to the control  
board, communicates PRO-CUT 25 status and  
operating conditions to the user. There are four status  
indicators: Power On, Gas Pressure, Thermal  
Overload, and Safety Error.  
PRO-CUT 25  
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E-7  
E-7  
THEORY OF OPERATION  
PROTECTION CIRCUITS  
ACCIDENTAL OPERATION  
PROTECTION  
Protection circuits are designed into the PRO-CUT 25  
machine to sense trouble, damages, problems with  
internal components, and to provide safety. These are  
the main protection circuits:  
The PRO-CUT 25 has two protection circuits to  
eliminate accidental pilot arc initiation. These two  
circuits operate when the machine is first turned on  
and after a thermal overload occurs. In these cases,  
the first time the torch trigger is activated nothing will  
happen. The torch trigger must be activated a second  
time before pilot arc initiation occurs. This protection  
is added in case the machine is turned on and the trig-  
ger is already activated or if a thermal overload self  
resets and the trigger is activated.  
OVERLOAD PROTECTION  
The PRO-CUT 25 is electrically protected from  
producing higher than normal output currents. If the  
output current exceeds 25-30 amps, an electronic  
protection circuit limits the current to within the  
capabilities of the machine. A second circuit monitors  
the input voltage and the voltage across the input filter  
capacitors. If the input voltage or filter capacitor  
voltage is too high, or too low, the protection circuit  
will prevent machine output.  
SAFETY PARTS-IN-PLACE  
PROTECTION  
The PRO-CUT 25 has protection circuits to detect the  
proper connection of the torch and the proper  
installation of the consumables. If an error is detected  
with either of these two items, the Safety status LED  
will be turned on and the output of the machine will be  
disabled. The PRO-CUT 25 must be turned off and  
the problem must be corrected before normal  
operation can occur.  
THERMAL PROTECTION  
Three thermal protection devices protect the machine  
from excessive operating temperatures. One device  
is located on the output choke, one is located inside  
the main transformer, and another is mounted on one  
of the IGBT heat sinks. Excessive temperatures may  
be caused by a lack of cooling air or by operating the  
machine beyond the duty cycle and output rating. If  
excessive operating temperatures should occur, the  
thermal status indicator will turn on and the thermostat  
will prevent output voltage or current. The thermal  
protection devices are self-resetting once the machine  
cools sufficiently. If the shutdown was caused by  
excessive output or duty cycle and the fans are  
operating normally, the power switch may be left on  
and the reset should occur within a 15 minute period.  
If the fan is not turning or the air intake louvers are  
obstructed, the input power must be removed and the  
fan problem or air obstruction must be corrected.  
After a thermal overload occurs and the machine  
resets, it may be necessary to activate the torch  
trigger twice before a pilot arc will be initiated. This is  
a safety precaution, to eliminate accidental pilot arc  
initiation when the thermal protection self resets.  
PRO-CUT 25  
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E-8  
E-8  
THEORY OF OPERATION  
INSULATED GATE BIPOLAR  
TRANSISTOR (IGBT) OPERATION  
An IGBT is a type of transistor. IGBTs are semicon-  
ductors well suited for high frequency switching and  
high current applications.  
Drawing B shows the IGBT in an active mode. When  
the gate signal, a positive DC voltage relative to the  
source, is applied to the gate terminal of the IGBT, it  
is capable of conducting current. A voltage supply  
connected to the drain terminal will allow the IGBT to  
conduct and supply current to circuit components  
coupled to the source. Current will flow through the  
conducting IGBT to downstream components as long  
as the positive gate signal is present. This is similar  
to turning ON a light switch.  
Drawing A shows an IGBT in a passive mode. There  
is no gate signal, zero volts relative to the source, and  
therefore, no current flow. The drain terminal of the  
IGBT may be connected to a voltage supply; but since  
there is no conduction the circuit will not supply  
current to components connected to the source. The  
circuit is turned off like a light switch in the OFF  
position.  
FIGURE E.5 – IGBT  
POSITIVE  
VOLTAGE  
APPLIED  
GATE  
GATE  
SOURCE  
SOURCE  
n +  
n +  
n +  
n +  
p
BODY REGION  
p
BODY REGION  
DRAIN DRIFT REGION  
DRAIN DRIFT REGION  
n -  
n -  
n +  
p +  
BUFFER LAYER  
n +  
p +  
BUFFER LAYER  
INJECTING LAYER  
INJECTING LAYER  
DRAIN  
DRAIN  
B. ACTIVE  
A. PASSIVE  
PRO-CUT 25  
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Section F-1  
Section F-1  
TABLE OF CONTENTS  
TROUBLESHOOTING & REPAIR SECTION  
Troubleshooting & Repair Section.................................................................................Section F  
How to Use Troubleshooting Guide ....................................................................................F-2  
PC Board Troubleshooting Procedures and Replacement .................................................F-3  
Troubleshooting Guide ........................................................................................................F-4  
Test Procedures  
Input Filter Capacitor Discharge Procedure .................................................................F-9  
Main Inverter Board Resistance Test ............................................................................F-11  
Input Board Voltage Test...............................................................................................F-17  
Main Inverter Board Voltage Test..................................................................................F-21  
Torch Continuity and Solenoid Test ..............................................................................F-25  
Air/Gas Solenoid Test....................................................................................................F-29  
Replacement Procedures  
Control Board Removal and Replacement ...................................................................F-31  
Input Board Removal and Replacement.......................................................................F-35  
Main Inverter Board Removal and Replacement..........................................................F-39  
Switch Removal and Replacement...............................................................................F-43  
Fan Removal and Replacement....................................................................................F-45  
Retest after Repair ........................................................................................................F-48  
PRO-CUT 25  
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F-2  
F-2  
TROUBLESHOOTING & REPAIR  
HOW TO USE TROUBLESHOOTING GUIDE  
CAUTION  
Service and repair should be performed by only Lincoln Electric Factory Trained Personnel.  
Unauthorized repairs performed on this equipment may result in danger to the technician and machine  
operator and will invalidate your factory warranty. For your safety and to avoid Electrical Shock, please  
observe all safety notes and precautions detailed throughout this manual.  
This Troubleshooting Guide is provided to help  
you locate and repair possible machine  
malfunctions. Simply follow the three-step  
procedure listed below.  
Step 3. PERFORM COMPONENT TESTS. The  
last column, labeled “Recommended Course of  
Action” lists the most likely components that may  
have failed in your machine. It also specifies the  
appropriate test procedure to verify that the  
subject component is either good or bad. If there  
are a number of possible components, check the  
components in the order listed to eliminate one  
possibility at a time until you locate the cause of  
your problem.  
Step 1. LOCATE PROBLEM (SYMPTOM). Look  
under the column labeled “PROBLEM  
(SYMPTOMS)”. This column describes possible  
symptoms that the machine may exhibit. Find  
the listing that best describes the symptom that  
the machine is exhibiting. Symptoms are  
grouped into three main categories: Output  
Problems, Function Problems, and LED Function  
Problems.  
All of the referenced test procedures referred to in  
the Troubleshooting Guide are described in detail  
at the end of this chapter. Refer to the  
Troubleshooting and Repair Table of Contents to  
locate each specific Test Procedure. All of the  
referred to test points, components, terminal  
strips, etc., can be found on the referenced  
electrical wiring diagrams and schematics. Refer  
to the Electrical Diagrams Section Table of  
Contents to locate the appropriate diagram.  
Step 2. PERFORM EXTERNAL TESTS. The  
second column, labeled “POSSIBLE AREAS OF  
MISADJUSTMENT(S)”, lists the obvious external  
possibilities that may contribute to the machine  
symptom. Perform these tests/checks in the  
order listed. In general, these tests can be  
conducted without removing the case  
wrap-around cover.  
CAUTION  
If for any reason you do not understand the test procedures or are unable to perform the test/repairs  
safely, contact the Lincoln Electric Service Department for electrical troubleshooting assistance before  
you proceed. Call 1-888-935-3877  
PRO-CUT 25  
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F-3  
F-3  
TROUBLESHOOTING & REPAIR  
PC BOARD TROUBLESHOOTING PROCEDURES  
• Remove the PC Board from the static-shielding bag  
and place it directly into the equipment. Don’t set  
the PC Board on or near paper, plastic or cloth which  
could have a static charge. If the PC Board can’t be  
installed immediately, put it back in the static-  
shielding bag.  
WARNING  
ELECTRIC SHOCK can kill.  
Have an electrician install and service  
this equipment. Turn the machine OFF  
before working on equipment. Do not  
touch electrically hot parts.  
• If the PC Board uses protective shorting jumpers,  
don’t remove them until installation is complete.  
• If you return a PC Board to The Lincoln Electric  
Company for credit, it must be in the static-shielding  
bag. This will prevent further damage and allow  
proper failure analysis.  
Sometimes machine failures appear to be due to PC  
board failures. These problems can sometimes be  
traced to poor electrical connections. To avoid prob-  
lems when troubleshooting and replacing PC boards,  
please use the following procedure:  
4. Test the machine to determine if the failure symp-  
tom has been corrected by the replacement PC  
board.  
1. Determine to the best of your technical ability that  
the PC board is the most likely component caus-  
ing the failure symptom.  
NOTE: Allow the machine to heat up so that all  
electrical components can reach their  
operating temperature.  
2. Check for loose connections at the PC board to  
assure that the PC board is properly connected.  
5. Remove the replacement PC board and substitute  
it with the original PC board to recreate the original  
problem.  
3. If the problem persists, replace the suspect PC  
board using standard practices to avoid static  
electrical damage and electrical shock. Read the  
warning inside the static resistant bag and perform  
the following procedures:  
a. If the original problem does not reappear  
by substituting the original board, then the  
PC board was not the problem. Continue  
to look for bad connections in the control  
wiring harness, junction blocks, and termi-  
nal strips.  
PC Board can be damaged by  
static electricity.  
b. If the original problem is recreated by the  
substitution of the original board, then the  
PC board was the problem. Reinstall the  
replacement PC board and test the  
machine.  
• Remove your body’s static  
charge before opening the static-  
shielding bag. Wear an anti-sta-  
tic wrist strap. For safety, use a  
1 Meg ohm resistive cord con-  
ATTENTION  
Static-Sensitive  
Devices  
Handle only at  
nected to a grounded part of the  
equipment frame.  
6. Always indicate that this procedure was followed  
when warranty reports are to be submitted.  
Static-Safe  
• If you don’t have a wrist strap,  
Workstations  
NOTE: Following this procedure and writing on the  
warranty report, “INSTALLED AND SWITCHED  
PC BOARDS TO VERIFY PROBLEM,” will help  
avoid denial of legitimate PC board warranty  
claims.  
touch an unpainted, grounded,  
part of the equipment frame.  
Keep touching the frame to  
prevent static build-up. Be sure  
not to touch any electrically live  
parts at the same time.  
Reusable  
Container  
Do Not Destroy  
Tools which come in contact with the PC Board must  
be either conductive, anti-static or static-dissipative.  
PRO-CUT 25  
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F-4  
F-4  
TROUBLESHOOTING & REPAIR  
Observe Safety Guidelines  
detailed in the beginning of this manual.  
TROUBLESHOOTING GUIDE  
PROBLEMS  
(SYMPTOMS)  
POSSIBLE AREAS OF  
MISADJUSTMENT(S)  
RECOMMENDED  
COURSE OF ACTION  
OUTPUT PROBLEMS  
Major physical or electrical dam- 1. Contact your local authorized 1. Contact the Lincoln Electric  
age is evident when the sheet  
metal cover(s) are removed.  
Lincoln Electric Field Service  
Facility for technical assistance.  
Service Department,  
1-888-935-3877  
Machine is dead – no output – no 1. Make sure that the input power 1. Check the input power switch  
fan – no status indicator lights. switch is in the “ON” position. for proper operation.  
2. Check the input voltage at the 2. Check the leads associated  
machine. Input voltage must  
match the rating plate.  
with the power switch for loose  
or faulty connections. See the  
Wiring Diagram.  
3. Check for blown or missing  
fuses in the input lines and the 3. Check all connectors and wires  
1A slow blow fuse on the input  
board.  
for loose or faulty connections.  
4. Perform the Input Voltage  
Board Test.  
Machine is malfunctioning - no 1. Check the input voltage at the 1. Check all connectors and wires  
output - no status indicator lights -  
fans run.  
machine. Input voltage must  
match the rating plate.  
for loose or faulty connections.  
See Wiring Diagram.  
2. Perform the Input Voltage  
Board Test.  
3. The control board may be  
faulty. Replace.  
CAUTION  
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-  
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call  
1-888-935-3877.  
PRO-CUT 25  
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F-5  
F-5  
TROUBLESHOOTING & REPAIR  
TROUBLESHOOTING GUIDE  
Observe Safety Guidelines  
detailed in the beginning of this manual.  
PROBLEMS  
(SYMPTOMS)  
POSSIBLE AREAS OF  
MISADJUSTMENT(S)  
RECOMMENDED  
COURSE OF ACTION  
FUNCTION PROBLEMS  
The machine powers up properly, 1. Make sure the torch handle or 1. Check all connectors and wires  
for loose or faulty connections.  
See Wiring Diagram.  
but there is no response (no air flow  
or pilot arc) when the torch trigger  
is pulled. Only the power LED is lit.  
cable is not damaged or pulled  
from the machine. Replace if  
necessary.  
2. Perform the Air/Gas  
Solenoid Test.  
2. Make sure the air supply is  
converted and operating  
properly.  
3. The control board may be  
faulty. Replace.  
The machine powers up properly, 1. Make sure the torch consum- 1. Check all connectors and wires  
but only air flows when the torch  
trigger is pulled; no pilot arc is  
established.  
ables are in place and in good  
condition. Replace if neces-  
sary.  
for loose or faulty connections.  
See Wiring Diagram.  
2
Perform the Torch Continuity  
2. Set air pressure at 65psi.  
and Solenoid Test.  
3. Make sure there are no kinks or 3. Perform the Main Inverter  
restrictions for air flow in the  
Board Voltage and  
torch cable.  
Resistance Tests.  
4. Make sure that the correct size 4. The control board may be  
nozzle is being used. Must be a  
.028 orifice. Pro-Cut 55 size  
nozzles will not work with the  
Pro-Cut 25 system.  
faulty. Replace.  
The machine powers up properly, 1. CP leads to its terminal from the 1. Reconnect the leads to its cor-  
rect terminal per the wiring dia-  
gram.  
and cuts OK with 230 input  
applied. With 115 applied the pilot  
arc ignites but goes out when cut-  
ting commences. Or, no pilot or  
cutting when 115 input is supplied.  
input to the inverter board are  
loose or disconnected.  
2. Perform the Input Board Test.  
3. The input board may be faulty.  
Replace.  
The air begins to flow when the 1. Check the input voltage at the  
1. Check all connectors and wires  
for loose or faulty connections.  
See Wiring Diagram.  
torch trigger is pulled. There is a  
very brief pilot arc. (Normal is 3  
Seconds.) The sequence is repeat-  
ed with subsequent trigger pulls.  
machine. Input voltage must  
match the rating plate.  
2. Make sure the torch  
consumable parts are in place  
and in good condition.  
Replace if necessary.  
2. Perform the Main Inverter  
Board Voltage and  
Resistance Tests.  
3. The control board may be  
faulty. Replace.  
3. Make sure there are no kinks or  
restrictions for air flow in the  
torch cable.  
4. Make sure the air pressure is  
set at 65psi.  
5. Make sure that the correct size  
nozzle is being used. Must be a  
.028 orifice. Pro-Cut 55 size  
nozzles will not work with the  
PC 25 system.  
PRO-CUT 25  
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F-6  
F-6  
TROUBLESHOOTING & REPAIR  
Observe Safety Guidelines  
detailed in the beginning of this manual.  
TROUBLESHOOTING GUIDE  
PROBLEMS  
(SYMPTOMS)  
POSSIBLE AREAS OF  
MISADJUSTMENT(S)  
RECOMMENDED  
COURSE OF ACTION  
FUNCTION PROBLEMS  
The cutting arc starts but sputters 1. Make sure the operating proce- 1. Check all connectors and  
badly.  
dure is correct for the process.  
See the Operation section of  
the manual.  
wires for loose or faulty con-  
nections. See Wiring Diagram.  
2. Perform the Torch Continuity  
2. Make sure the work clamp is  
connected tightly to the work  
piece.  
and Solenoid Test.  
3. Perform the Main Inverter  
Board Voltage and Resistance  
Tests.  
3. Make sure the torch consum-  
able parts are in place and in  
good condition. Replace if  
necessary.  
4. The control board may be  
faulty. Replace.  
5. Use the correct extension cord.  
See the instruction manual.  
4. Make sure the air pressure is  
set at 65psi.  
5. Make sure the air supply is not  
contaminated with oil or  
excessive water.  
The pilot arc is normal, but the arc 1. Make sure the operating 1. Check all connectors and  
will not transfer to the work piece.  
procedure is correct for the  
process. See the Operation  
section of the manual.  
wires for loose or faulty con-  
nections. See Wiring Diagram.  
2. Perform the Main Inverter  
Board Voltage and Resistance  
Tests.  
2. Make sure the work clamp is  
connected tightly to the work  
piece.  
3. The control board may be  
faulty. Replace.  
3. The work piece must be electri-  
cally conductive material, and  
the work clamp must make a  
good electrical connection with  
the work piece.  
4. Do not use a drag cup. Not  
recommended for Pro-Cut 25  
use.  
Trigger or purge is activated brief  
air flow then the safety light illumi-  
nates.  
1. The Control Board is defective.  
Replace.  
Poor performance of pilot arc or 1. Check pressure switch to be 1. Try increasing or decreasing the  
cutting. Poor consumable life.  
functioning  
(opening/closing) at its correct  
pressure.  
correctly  
air pressure to see if conditions  
improve.  
2. Replace regulator or pressure  
switch may be required.  
2. Check pressure gauge to be  
correct in its reading.  
3. Screen in air line at inlet to air  
solenoid may be clogged.  
Clean. (no screen before 7/1/02)  
3. Check for recommended flow  
rate coming from the torch end  
with a flow meter.  
4. Ensure that air is clean and dry  
External filters may be used.  
PRO-CUT 25  
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F-7  
F-7  
TROUBLESHOOTING & REPAIR  
Observe Safety Guidelines  
detailed in the beginning of this manual.  
TROUBLESHOOTING GUIDE  
PROBLEMS  
POSSIBLE AREAS OF  
RECOMMENDED  
(SYMPTOMS)  
MISADJUSTMENT(S)  
COURSE OF ACTION  
FUNCTION PROBLEMS  
Will only cut thin gauge material or The ground lead or clamp is dis- 1. Replace or repair, clamp or  
cutting cutting is 1/2 of what it connected. Unit is not transferring  
should be. Cuts for 3 seconds to cut mode.  
then quits.  
cable.  
2. Clamp directly to the piece to  
be cut.  
3. Look for the transfer signal from  
the inverter board to the control  
Board per the enhanced dia-  
gram.  
4. Possible replacement of the  
inverter board per the signal of  
the enhanced diagram.  
5. Possible replacement of the  
Control Board per the signal of  
the enhanced diagram.  
6. Use the correct extension cord.  
See the instruction manual.  
When nothing is described for your  
problem, or you have performed  
your test with no solution.  
1. Unplug and re-plug in all the  
printed circuit board harness  
connectors.  
CAUTION  
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-  
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed.  
Call 1-888-935-3877.  
PRO-CUT 25  
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F-8  
F-8  
TROUBLESHOOTING & REPAIR  
Observe Safety Guidelines  
detailed in the beginning of this manual.  
TROUBLESHOOTING GUIDE  
PROBLEMS  
POSSIBLE AREAS OF  
RECOMMENDED  
(SYMPTOMS)  
MISADJUSTMENT(S)  
COURSE OF ACTION  
LED FUNCTION PROBLEMS  
The Thermal LED is lit after normal 1. One of the machine’s thermal 1. Check all connectors and wires  
use.  
protection circuits has tripped.  
Do not turn the PRO-CUT 25 off.  
Allow the machine to cool. The  
thermal protection circuits will  
reset themselves.  
for loose or faulty connections.  
See Wiring Diagram.  
2. The inverter board may be  
faulty. Replace.  
3. The control board may be faulty.  
Replace.  
2. Either the duty cycle has been  
exceeded, the fan is not func-  
tioning, or the louvers are 4. Use the correct extension cord.  
blocked.  
See the instruction manual.  
3. Thermo light comes on when  
over voltage occurs +/-10%  
must be with in 10%.  
CAUTION  
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-  
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed.  
Call 1-888-935-3877.  
PRO-CUT 25  
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F-9  
F-9  
TROUBLESHOOTING & REPAIR  
INPUT FILTER CAPACITOR DISCHARGE PROCEDURE  
WARNING  
Service and repair should be performed by only Lincoln Electric factory trained  
personnel. Unauthorized repairs performed on this equipment may result in danger to  
the technician or machine operator and will invalidate your factory warranty. For your  
safety and to avoid electrical shock, please observe all safety notes and precautions  
detailed throughout this manual.  
If for any reason you do not understand the test procedures or are unable to perform the  
test/repairs safely, contact the Lincoln Electric Service Department for electrical  
troubleshooting assistance before you proceed. Call 1-888-935-3877.  
DESCRIPTION  
This procedure will drain off any charge stored in the four capacitors that are part of the  
Inverter Board assembly. This procedure MUST be performed, as a safety precaution,  
before conducting any test or repair procedure that requires you to touch internal  
components of the machine.  
MATERIALS NEEDED  
4mm Allen Wrench  
Volt/Ohmmeter  
7mm Nut Driver  
Crescent Wrench  
Insulated Gloves  
Insulated Pliers  
High Wattage Resistor - 25 to 1000 ohms, 25 watts minimum  
PRO-CUT 25  
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F-10  
F-10  
TROUBLESHOOTING & REPAIR  
INPUT FILTER CAPACITOR DISCHARGE PROCEDURE (continued)  
5. Be careful not to make contact with the capacitor  
terminals located at the top of the main inverter  
Board.  
WARNING  
ELECTRIC SHOCK can kill.  
6. Obtain a high resistance and high wattage resistor  
(25-1000 ohms and 25 watts minimum). This  
resistor is not supplied with machine. NEVER USE  
A SHORTING STRAP FOR THIS PROCEDURE.  
• Have an electrician install and service  
this equipment.  
Turn the input power off at the fuse box  
before working on equipment.  
7. Locate the eight capacitor terminals located at the  
top rear of the main inverter board. See Figure F.1  
• Do not touch electrically hot parts.  
8. Use electrically insulated gloves and insulated pli-  
ers. Hold the body of the resistor and connect the  
resistor leads across the two capacitor terminals.  
Hold the resistor in place for 10 seconds. DO NOT  
TOUCH CAPACITOR TERMINALS WITH YOUR  
BARE HANDS.  
• Prior to performing preventative maintenance,  
perform the following capacitor discharge procedure  
to avoid electric shock.  
DISCHARGE PROCEDURE  
1. Remove input power to the PRO-CUT 25 machine.  
9. Repeat the discharge procedure for the other  
capacitors.  
2. Remove carrying handle using a 4mm allen  
wrench.  
10. Check the voltage across the terminals of all  
capacitors with a DC voltmeter. Voltage should  
be zero. If any voltage remains, repeat this  
capacitor discharge procedure.  
3. Using a crescent wrench, carefully remove the  
plastic nut from around the pressure regulator  
located on the top of the machine.  
4. Using a 7mm nut driver, remove the case  
wraparound.  
FIGURE F.1 – LOCATION OF INPUT FILTER CAPACITOR TERMINALS  
CAPACITOR  
TERMINALS  
INSULATED  
PLIERS  
INSULATED  
GLOVES  
RIGHT SIDE OF MACHINE  
POWER  
RESISTOR  
PRO-CUT 25  
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F-11  
F-11  
TROUBLESHOOTING & REPAIR  
MAIN INVERTER BOARD RESISTANCE TEST  
WARNING  
Service and repair should be performed by only Lincoln Electric factory trained personnel.  
Unauthorized repairs performed on this equipment may result in danger to the technician or  
machine operator and will invalidate your factory warranty. For your safety and to avoid  
electrical shock, please observe all safety notes and precautions detailed throughout this  
manual.  
If for any reason you do not understand the test procedures or are unable to perform the  
test/repairs safely, contact the Lincoln Electric Service Department for electrical  
troubleshooting assistance before you proceed. Call 1-888-935-3877.  
DESCRIPTION  
This test will determine if the main inverter board has any “shorted” or “leaky” power diodes  
or Insulated Gate Bipolar Transistors IGBT’s. Also it will indicate if P1 is “shorted” or “open”.  
MATERIALS NEEDED  
Analog Volt/Ohmmeter  
Wiring Diagram  
7mm Nut Driver  
4mm Allen Wrench  
Crescent Wrench  
PRO-CUT 25  
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F-12  
F-12  
TROUBLESHOOTING & REPAIR  
MAIN INVERTER BOARD RESISTANCE TEST (continued)  
FIGURE F.2  
P1  
LEAD 2 (NZL)  
WRK  
LEAD 3  
(EL)  
Plug J1  
Harness  
Plug  
RIGHT SIDE OF MACHINE  
TEST PROCEDURE  
1. Remove main input power to the PRO-CUT  
25.  
5. Perform the Input Filter Capacitor Discharge  
Procedure detailed earlier in this section.  
2. Remove carrying handle using a 4mm allen  
wrench.  
6. Visually check for burned or damaged compo-  
nents. If any components are physically dam-  
aged or determined to be faulty, the Main  
Inverter Board should be replaced.  
3. Using a crescent wrench, carefully remove the  
plastic nut from around the pressure  
regulator located on the top of the machine.  
7. Check the input rectifier bridge (P1) for  
shorts or opens. See Figure F.2  
4. Using a 7mm nut driver, remove the case  
wraparound.  
PRO-CUT 25  
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F-13  
F-13  
TROUBLESHOOTING & REPAIR  
MAIN INVERTER BOARD RESISTANCE TEST (continued)  
8. Check the IGBTs for “shorts”. Check each IGBT (6)  
from Gate to Collector. Normal resistance is approx-  
imately 100 ohms.  
Also check each device from Gate to Emitter.  
Normal resistance is approximately 40 ohms.  
Check each device from Emitter to Collector.  
Normal reading is high resistance in one polarity  
and a low resistance in the opposite polarity.  
Note: These devices will usually fail “short”resulting  
in a zero or very low resistance reading. If they  
“open” physical damage should be evident.  
S
FIGURE F.3 LOCATION OF IGBT (6)  
LEAD 2 (NZL)  
WRK  
LEAD 3  
(EL)  
Plug J1  
IGBT’s  
(6)  
Harness  
Plug  
RIGHT SIDE OF MACHINE  
GCE  
PRO-CUT 25  
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F-14  
F-14  
TROUBLESHOOTING & REPAIR  
MAIN INVERTER BOARD RESISTANCE TEST (continued)  
9. Check Diodes D1, D2, & D3 for “shorts” or  
“opens”. Keep in mind that unless these devices  
are electrically isolated from the circuit, some  
resistance will be read in both polarities. See the  
Wiring Diagram.  
Figure F.4  
LEAD 2 (NZL)  
WRK  
D3  
LEAD 3  
(EL)  
Plug J1  
D2  
D1  
Harness  
Plug  
RIGHT SIDE OF MACHINE  
D1, D2, & D3  
D3  
D1  
D2  
PRO-CUT 25  
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F-15  
F-15  
TROUBLESHOOTING & REPAIR  
MAIN INVERTER BOARD RESISTANCE TEST (continued)  
10.  
Remove the torch consumables. (Shield  
cup, Nozzle and Electrode)  
12.  
With the Torch Consumables removed test  
the snubber diodes. (D8 and D9) See the  
Wiring Diagram. See Figure F.5.  
11.  
With the Torch Consumables removed test  
the output diodes. (D10 and D11) See the  
Wiring Diagram.  
13.  
Replace the torch consumables  
previously removed. Check the resistance  
across output diode D11. The resistance  
should be very low, near or at zero ohms.  
This verifies that the pilot arc circuit is  
complete. See the Wiring Diagram.  
Figure F.5  
D11  
D9  
D8  
D10  
LEAD 2 (NZL)  
WRK  
LEAD 3  
(EL)  
Plug J1  
Harness  
Plug  
RIGHT SIDE OF MACHINE  
PRO-CUT 25  
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F-16  
F-16  
NOTES  
PRO-CUT 25  
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F-17  
F-17  
TROUBLESHOOTING & REPAIR  
INPUT BOARD VOLTAGE TEST  
WARNING  
Service and repair should be performed by only Lincoln Electric factory trained personnel.  
Unauthorized repairs performed on this equipment may result in danger to the technician or  
machine operator and will invalidate your factory warranty. For your safety and to avoid  
electrical shock, please observe all safety notes and precautions detailed throughout this  
manual.  
If for any reason you do not understand the test procedures or are unable to perform the  
test/repairs safely, contact the Lincoln Electric Service Department for electrical  
troubleshooting assistance before you proceed. Call 1-888-935-3877.  
DESCRIPTION  
This test will help determine if the correct input voltage is being applied to the input board  
and will also determine if the correct voltages are being processed and regulated on the  
input board.  
MATERIALS NEEDED  
Volt/Ohmmeter  
7mm Nut Driver  
4mm Allen Wrench  
Crescent Wrench  
PRO-CUT 25  
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F-18  
F-18  
TROUBLESHOOTING & REPAIR  
INPUT BOARD VOLTAGE TEST (CONTINUED)  
TEST PROCEDURE  
8. Apply 115VAC input to the PRO-CUT 25  
machine. The test should be performed  
with 115VAC applied. Not 230VAC.  
1. Remove input power to the PRO-CUT 25  
machine.  
2. Remove carrying handle using a 4mm  
allen wrench.  
Note: If the peak input voltage is above  
400VAC the thermal light may activate.  
Reduce the input voltage.  
3. Using  
a
crescent wrench, carefully  
remove the plastic nut from around the  
pressure regulator located on the top of  
the machine.  
9. Turn on the machine and carefully check  
for 115VAC (+/- 10%) at points A and B.  
See Figure F.6. See the Wiring  
Diagram.  
4. Using a 7mm nut driver, remove the case  
wraparound.  
5. Perform the Capacitor Discharge  
Procedure detailed earlier in this  
section.  
Note: Within 4 seconds of the machine  
being turned on, the two relays RL2 and  
RL3 should activate. If they don’t, the  
input board is faulty.  
6. Visually check for burned or damaged  
components on the input board. If any  
components are physically damaged or  
determined to be faulty (except the fuse)  
the input board should be replaced.  
7. Check fuse F1 (1 amp). Replace if  
defective.  
Figure F.6 Input Board Description  
TEST POINTS  
F1  
AC  
A B  
RL3  
AC  
RL2  
CP  
V1  
V2  
1 2 3 4 5 6 7 8  
PLUG CN1  
PRO-CUT 25  
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F-19  
F-19  
TROUBLESHOOTING & REPAIR  
INPUT BOARD VOLTAGE TEST (CONTINUED)  
10. After the relays activate check for  
13. With the torch consumables in place  
(nozzle, electrode and shield) check  
for the presence of approximately  
6VDC at pins 3(-) and 4(+) of plug CN1.  
See Figure F.7.  
115VAC from both test points AC to  
CP. See Figure F.7. If this voltage is  
not present or low, the relay contacts  
may be defective.  
Note: With the torch consumables  
removed this voltage should be  
approximately 26VDC.  
11. Check the fan voltage at the fan  
terminals (V1 & V2). See Figure F.7  
Normal is 230VAC. If this voltage is  
normal (230VAC) the primary circuit of  
the auxiliary transformer is operating  
correctly.  
14. If the relays (RL2 and RL3) are activating  
with 115VAC applied to the machine  
and the above test voltages are correct  
the input board is functioning correctly.  
12. Check for the presence of  
approximately 15VAC at pins 1 and 2  
of plug CN1. See Figure F.7.  
Figure F.7 Input Board Test Points  
F1  
AC  
A B  
RL3  
AC  
RL2  
Fan  
Leads  
CP  
V1  
V2  
1 2 3 4 5 6 7 8  
PLUG CN1  
PRO-CUT 25  
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F-20  
F-20  
NOTES  
PRO-CUT 25  
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F-21  
F-21  
TROUBLESHOOTING & REPAIR  
MAIN INVERTER BOARD VOLTAGE TEST  
WARNING  
Service and repair should be performed by only Lincoln Electric factory trained personnel.  
Unauthorized repairs performed on this equipment may result in danger to the technician or  
machine operator and will invalidate your factory warranty. For your safety and to avoid  
electrical shock, please observe all safety notes and precautions detailed throughout this  
manual.  
If for any reason you do not understand the test procedures or are unable to perform the  
test/repairs safely, contact the Lincoln Electric Service Department for electrical  
troubleshooting assistance before you proceed. Call 1-888-935-3877.  
DESCRIPTION  
This test will help determine if the main inverter board is receiving the correct input voltages  
and if the correct regulated voltages are being processed and maintained by the main  
inverter board.  
MATERIALS NEEDED  
Volt/Ohmmeter  
7mm Nut Driver  
4mm Allen Wrench  
Crescent Wrench  
PRO-CUT 25  
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F-22  
F-22  
TROUBLESHOOTING & REPAIR  
MAIN INVERTER BOARD VOLTAGE TEST (CONTINUED)  
TEST PROCEDURE  
7. Apply the correct input power to the  
Pro-Cut 25 machine. (115VAC or  
230VAC)  
1. Remove input power to the PRO-CUT  
25 machine.  
2. Remove carrying handle using a 4mm  
allen wrench.  
8. Carefully test for approximately 300VDC  
at the P1 bridge terminals.  
3. Using a crescent wrench, carefully  
remove the plastic nut from around the  
pressure regulator located on the top of  
the machine.  
See Figure F.8. This represents the  
rectified voltage supplied from the input  
board. See the Wiring Diagram.  
9. Carefully test for approximately 15VAC  
at the test points on bridge P2. This is  
the control supply voltage from the  
input board. See Figure F.8. See the  
Wiring Diagram.  
4. Using a 7mm nut driver, remove the case  
wraparound.  
5. Perform the Capacitor Discharge  
Procedure detailed earlier in this  
section.  
10. Carefully test for 12VDC at test points  
C17. See Figure F.8. See Wiring  
Diagram. This is the rectified and  
regulated DC supply voltage for the  
inverter board control circuitry.  
6. Visually check for burned or damaged  
components on the input board. If any  
components are physically damaged or  
determined to be faulty (except the  
fuse) the input board should be  
replaced.  
Figure F.8. Test Points  
P2  
P1  
AC  
+
+
C18  
C17  
+
AC  
LEAD 2 (NZL)  
WRK  
C19  
C7  
LEAD 3  
(EL)  
Plug J1  
Harness  
Plug  
RIGHT SIDE OF MACHINE  
PRO-CUT 25  
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F-23  
F-23  
TROUBLESHOOTING & REPAIR  
MAIN INVERTER BOARD VOLTAGE TEST (CONTINUED)  
10. Carefully test for 12VDC at test points  
C7. See Figure F.9. See the Wiring  
Diagram. This is the rectified and  
regulated supply for the pulse width  
modulation circuit.  
12. Carefully check for the presence of  
8VDC at C19 test points. If not correct  
the control board or associated wiring  
may be faulty. See Figure F.9.  
See the Wiring Diagram.  
11. Carefully test for 12VDC at C18 test  
points. If it is not correct the control  
board or associated wiring may be  
faulty. See the Wiring Diagram. See  
Figure F.9.  
Figure F.9 Test Points  
P2  
P1  
AC  
+
+
C18  
C17  
+
AC  
LEAD 2 (NZL)  
WRK  
C19  
C7  
LEAD 3  
(EL)  
Plug J1  
+
Harness  
Plug  
+
RIGHT SIDE OF MACHINE  
PRO-CUT 25  
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F-24  
F-24  
NOTES  
PRO-CUT 25  
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F-25  
F-25  
TROUBLESHOOTING & REPAIR  
TORCH CONTINUITY AND SOLENOID TEST  
WARNING  
Service and repair should be performed by only Lincoln Electric factory trained personnel.  
Unauthorized repairs performed on this equipment may result in danger to the technician or  
machine operator and will invalidate your factory warranty. For your safety and to avoid  
electrical shock, please observe all safety notes and precautions detailed throughout this  
manual.  
If for any reason you do not understand the test procedures or are unable to perform the  
test/repairs safely, contact the Lincoln Electric Service Department for electrical  
troubleshooting assistance before you proceed. Call 1-888-935-3877.  
DESCRIPTION  
This procedure will help the technician determine if the torch cable, consumables and elec-  
trode solenoid are functioning properly.  
MATERIALS NEEDED  
Volt/Ohmmeter  
12 VDC @ 1 Amp Power Supply  
7mm Nut Driver  
4mm Allen Wrench  
Crescent Wrench  
PRO-CUT 25  
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F-26  
F-26  
TROUBLESHOOTING & REPAIR  
TORCH CONTINUITY AND SOLENOID TEST (continued)  
FIGURE F.10  
LEAD 2 (NZL)  
WRK  
(EL)  
LEAD 3  
Plug J1  
Harness  
Plug  
Electrode is  
insulated from  
Brass Body  
Electrode Lead  
EL (3)  
Connector  
3
4
Blue Leads  
outside  
flex tubes  
center  
Torch Solenoid  
Vent Tube  
White & Black Pairs  
NZL (2)  
Air Hose  
1
2
Red Leads  
N.O.  
Torch Trigger  
7. Using the ohmmeter, check the torch  
TEST PROCEDURE  
resistances per Table F.1.  
1. Remove input power to the PRO-CUT 25  
machine.  
8. If any of the resistance checks are not cor-  
rect, the torch assembly may be faulty.  
Repair or replace.  
2. Remove carrying handle using a 4mm allen  
wrench.  
9. With connector J1 disconnected from the  
P.C. Board carefully apply the 12 VDC supply  
to the electrode solenoid. (positive to Plug  
J1 Pin #4 and Negative to Pin #3). The elec-  
trode solenoid should activate. Listen for the  
solenoid action in the torch handle. If the  
solenoid does not activate, it may be faulty.  
Replace. See Figures F.10 & F.11.  
3. Using a crescent wrench, carefully remove  
the plastic nut from around the pressure  
regulator located on the top of the machine.  
4. Using a 7mm nut driver, remove the case  
wraparound.  
5. Perform the Capacitor Discharge  
Procedure.  
6. Remove Plug J1, Lead #2, and Lead #3 from  
the Main Inverter Board. See Figure F.10  
PRO-CUT 25  
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F-27  
F-27  
TROUBLESHOOTING & REPAIR  
TORCH CONTINUITY AND SOLENOID TEST (continued)  
TABLE F.1 - TORCH ASSEMBLY RESISTANCES  
TEST  
POINTS  
CIRCUIT(S) BEING  
TESTED  
EXPECTED  
RESISTANCE  
TEST  
CONDITIONS  
Lead #2  
To Lead #3  
Pilot arc  
leads  
1.5 ohms maximum  
1.0 ohm maximum  
1.0 ohm maximum  
100K ohms minimum  
1.0 ohm maximum  
45 to 55 ohms  
Torch consumables  
in place  
Lead #2 to Torch  
Nozzle  
Pilot arc lead to  
nozzle  
Torch consumables  
in place  
Lead #3 to Torch  
Nozzle  
Pilot arc lead to  
nozzle  
Torch consumables  
in place  
Pin 1 to Pin 2  
Plug J1 (Red Leads)  
Torch trigger circuit  
Torch trigger circuit  
Electrode Solenoid  
Torch trigger NOT  
pulled (not activated)  
Pin 1 to Pin 2  
Plug J1 (Red Leads)  
Torch trigger pulled  
(activated)  
Pin 3 to Pin 4  
None  
Plug J1 (Gray Leads)  
Figure F.11  
(LEAD 2) NZL  
WRK  
(LEAD 3) EL  
4
2
3
1
Harness  
Plug J1  
10. Torch circuits may be measured when elec-  
trode and nozzle are in place if the various cir-  
cuits are isolated from each other. NZL (2),  
Electrode (3), Trigger (1,2), and Torch leads (3,4)  
should all measure greater than 1 Meg ohm when  
checked as isolated circuits. See Figure F.10  
Diagram.  
11. Replace leads and plugs previously  
removed.  
PRO-CUT 25  
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F-28  
F-28  
NOTES  
PRO-CUT 25  
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F-29  
F-29  
TROUBLESHOOTING & REPAIR  
AIR/GAS SOLENOID TEST  
WARNING  
Service and repair should be performed by only Lincoln Electric factory trained personnel.  
Unauthorized repairs performed on this equipment may result in danger to the technician or  
machine operator and will invalidate your factory warranty. For your safety and to avoid  
electrical shock, please observe all safety notes and precautions detailed throughout this  
manual.  
If for any reason you do not understand the test procedures or are unable to perform the  
test/repairs safely, contact the Lincoln Electric Service Department for electrical  
troubleshooting assistance before you proceed. Call 1-888-935-3877.  
DESCRIPTION  
This procedure will help the technician determine if the solenoid is functioning properly.  
MATERIALS NEEDED  
4mm Allen Wrench  
7mm Nut Driver  
12 VDC @ 3 Amp Power Supply  
Volt/Ohmmeter  
Crescent Wrench  
PRO-CUT 25  
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F-30  
F-30  
TROUBLESHOOTING & REPAIR  
AIR/GAS SOLENOID TEST (continued)  
FIGURE F.12 – AIR SOLENOID  
Air Solenoid  
A
B
LEFT SIDE OF MACHINE  
TEST PROCEDURE  
7. Check the coil resistance of the solenoid at  
the two terminals. Normal resistance is  
approximately 13 ohms. If the resistance is  
abnormal, the Solenoid may be defective.  
1. Remove input power to the PRO-CUT 25  
machine.  
2. Remove carrying handle using a 4mm allen  
wrench.  
8. Carefully apply the 12 VDC supply to the  
solenoids lower two terminals. With proper  
air pressure applied, the solenoid should  
activate and air should flow from the torch  
nozzle. If the solenoid activates but air does  
not flow, check for a restriction in the air line  
or torch.  
3. Using a crescent wrench, carefully remove  
the plastic nut from around the pressure  
regulator located on the top of the machine.  
4. Using a 7mm nut driver, remove the case  
wraparound.  
5. Perform the Input Capacitor Discharge  
9. Reinstall the two leads previously removed.  
Procedure detailed earlier in this section.  
6. Locate the air solenoid and leads. Carefully  
remove the two leads from the Solenoid. See  
Figure F.12.  
PRO-CUT 25  
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F-31  
F-31  
TROUBLESHOOTING & REPAIR  
CONTROL BOARD REMOVAL AND REPLACEMENT  
WARNING  
Service and repair should be performed by only Lincoln Electric factory trained personnel.  
Unauthorized repairs performed on this equipment may result in danger to the technician or  
machine operator and will invalidate your factory warranty. For your safety and to avoid  
electrical shock, please observe all safety notes and precautions detailed throughout this  
manual.  
If for any reason you do not understand the test procedures or are unable to perform the  
test/repairs safely, contact the Lincoln Electric Service Department for electrical  
troubleshooting assistance before you proceed. Call 1-888-935-3877.  
DESCRIPTION  
The following procedure will aid the technician in removing the control board for maintenance  
or replacement.  
MATERIALS NEEDED  
Crescent Wrench  
Small Flathead Screwdriver  
7mm Nut Driver  
6mm Nut Driver  
4mm Allen Wrench  
2.5mm Allen Wrench  
Needle Nose Pliers  
PRO-CUT 25  
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F-32  
F-32  
TROUBLESHOOTING & REPAIR  
CONTROL BOARD REMOVAL AND REPLACEMENT (continued)  
FIGURE F.13 - CONTROL BOARD LOCATION  
Control  
Board  
PO  
WER  
ON  
G
AS PRESSURE  
TH  
ERM  
A
L
SAFETY  
!
PURGE  
OFF  
20  
15  
L
IN  
C
E
O
L
L
E
N
C
T
R
I
C
25  
R
E
Q
U
IR  
R
E
Q
E
E
S
U
20  
30  
IR  
A
/1  
/1  
S
15  
V
V
A
B
B
R
PR  
O-CUT 25  
15  
AN  
C
H
R
C
C
A
N
IR  
C
C
C
U
H
IT  
IT  
IR  
U
PROCEDURE  
5. Perform Capacitor Discharge Procedure.  
1. Remove input power to the PRO-CUT 25 machine.  
6. Using a very small flathead screwdriver or a thin  
knife blade, carefully remove the red plastic cap  
from the front of the plastic OUTPUT knob located  
on the front of the machine. See Figure F14.  
2. Remove carrying handle using a 4mm allen  
wrench.  
3. Using a crescent wrench, carefully remove the  
plastic nut from around the pressure regulator  
located on the top of the machine.  
4. Using a 7mm nut driver, remove the case wrap-  
around.  
FIGURE F.14 - SMALL RED CAP REMOVAL  
P
OW  
ER  
ON  
GAS PR  
ESSURE  
T
HERMAL  
SAFETY  
PURGE  
OFF  
!
20  
15  
L
IN  
C
E
O
L
L
C
T
E
N
R
IC  
25  
R
E
Q
U
IR  
R
E
E
Q
U
IR  
S
20  
30  
A
E
/1  
S
15  
15  
V
A
B
B
/1  
R
PR  
O-CUT 25  
AN  
V
C
H
R
C
C
A
N
IR  
C
C
C
U
H
IT  
IT  
IR  
U
Small Red  
Cap  
PRO-CUT 25  
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F-33  
F-33  
TROUBLESHOOTING & REPAIR  
CONTROL BOARD REMOVAL AND REPLACEMENT (continued)  
7. A nut is located under the red plastic piece that you  
previously removed. Loosen this nut with a 6mm  
nut driver and remove. Plastic alignment spacer  
may come off with knob.  
8. Next to the knob is a Red button that reads  
“PURGE”. Remove it by gently pulling.  
FIGURE F.15 - CASE FRONT SCREW REMOVAL  
P
O
W
E
R
O
G
N
A
S
P
R
E
S
S
U
R
E
T
H
E
R
M
A
L
S
A
F
!
PU  
E
O
T
FF  
Y
R
G
E
2
0
1
5
L
IN  
C
E
O
L
L
E
N
C
T
R
IC  
2
5
R
E
Q
U
IR  
R
E
E
E
S
Q
2
0
U
IR  
A
/1  
/1  
S
1
5
V
3
0
B
R
A
A
A
PR  
O-CUT 25  
1
5
N
V
C
H
B
R
C
IR  
IR  
N
C
H
C
U
IT  
C
C
U
IT  
3 Screws  
CAUTION  
11. Carefully remove the plug and lead assembly from  
the control board.  
Be sure to follow the recommended static-  
free methods for handling printed circuit  
boards. Failure to do so can result in per-  
manent damage to the equipment.  
12. At this point, the control board is ready for  
removal. GENTLY pull the case front forward and  
carefully remove the Control board.  
13. Replace the Control Board by GENTLY pulling the  
case front forward and carefully sliding the  
Control board back into its original position .  
Reconnect plug and lead assembly.  
9. Using a 7mm nut driver remove the three screws  
that hold the case front to the central metal wall.  
(This will allow the case front to be gently pulled  
forward so the Control board can be removed.)  
See Figure F.15.  
14. Replace the four allen mounting screws.  
15. Replace the screws connecting the case front to  
the central metal wall.  
10. Remove the Four allen bolts with a 2.5 mm allen  
wrench.  
PRO-CUT 25  
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F-34  
F-34  
TROUBLESHOOTING & REPAIR  
CONTROL BOARD REMOVAL AND REPLACEMENT (continued)  
16.  
17.  
Replace the red PURGE button.  
Replace the plastic OUTPUT knob,  
align it in its original position, and  
tighten nut.  
18.  
Replace the red cap on the end of  
the OUTPUT knob.  
19.  
20.  
Replace the case wraparound.  
Replace the plastic nut from around  
the pressure regulator. Do Not  
Over tighten.  
21.  
Replace the carry handle.  
PRO-CUT 25  
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F-35  
F-35  
TROUBLESHOOTING & REPAIR  
INPUT BOARD REMOVAL AND REPLACEMENT  
WARNING  
Service and repair should be performed by only Lincoln Electric factory trained personnel.  
Unauthorized repairs performed on this equipment may result in danger to the technician or  
machine operator and will invalidate your factory warranty. For your safety and to avoid  
electrical shock, please observe all safety notes and precautions detailed throughout this  
manual.  
If for any reason you do not understand the test procedures or are unable to perform the  
test/repairs safely, contact the Lincoln Electric Service Department for electrical  
troubleshooting assistance before you proceed. 1-888-935-3877.  
DESCRIPTION  
The following procedure will aid the technician in removing the input board for maintenance  
or replacement.  
MATERIALS NEEDED  
4 mm Allen Wrench  
Crescent Wrench  
7 mm Nut Driver  
Needle Nose Pliers  
PRO-CUT 25  
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F-36  
F-36  
TROUBLESHOOTING & REPAIR  
INPUT BOARD REMOVAL & REPLACEMENT (continued)  
FIGURE F.16 Input Board Location  
O
P
O
N
W
E
R
G
A
S
P
R
E
S
S
U
R
E
T
H
E
R
M
A
L
S
A
F
OFF  
P
E
!
Input Board  
U
T
Y
RG  
E
20  
15  
LIN  
C
EL  
O
LN  
CT  
R
E
IC  
12  
25  
R
EQ  
EQ  
U
R
IR  
ES  
U
2
0A  
IR  
P
ES  
/1  
1
5V  
/1  
15V  
3
0A  
BR  
R
O
AN  
AN  
B
C
H
R
C
IR  
CH  
CU  
C
IT  
IT  
IR  
C
U
-C  
U
T
25  
0
2
T
C
P
PROCEDURE  
6. Note the orientation of the input  
board to avoid confusion during  
reassembly.  
1. Remove input power to PRO-CUT 25.  
2. Remove carrying handle using a  
4mm allen wrench.  
7. Carefully label and remove cooling fan  
leads from Input Board. Pliers may be  
necessary. See Figure F.17.  
3. Using a crescent wrench, carefully  
remove the plastic nut from around the  
pressure regulator located on the top of  
the machine.  
8. Remove harness plug from lower right  
hand corner of board. Pliers may be  
necessary. See Figure F17.  
4. Using a 7mm nut driver, remove  
the case wraparound.  
9. Directly above the harness in step 8,  
there are four leads, CP(2) and AC(2).  
Label these leads and remove. Pliers  
may be necessary.  
5. Perform Capacitor Discharge Procedure.  
10. Using a 7mm nut driver, remove the two  
leads from terminals A and B on the  
input board. NOTE: The lead posts on  
the Input Board are labeled with an “A”  
and a “B”, so label the lead wires  
CAUTION  
Be sure to follow the recommended static-free  
methods for handling printed circuit boards.  
Failure to do so can result in permanent damage to  
the equipment.  
accordingly upon removal. Be careful  
not to misplace washers when bolts are  
removed. See Figure F.17.  
PRO-CUT 25  
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F-37  
F-37  
TROUBLESHOOTING & REPAIR  
INPUT BOARD REMOVAL & REPLACEMENT (continued)  
FIGURE F.17 – INPUT BOARD REMOVAL  
Mounting  
Screws  
Switch  
Leads  
A
B
AC  
AC  
Four  
Leads  
CP  
Fan  
Leads  
Multi-colored  
Plug  
Mounting  
Screws  
11. Using a 7mm Nut driver, remove the  
15. Reconnect the harness plug.  
four mounting nuts from the corners of  
the Input Board. Be careful not to lose  
the washer behind each nut. Input  
Board can be removed after these four  
nuts are removed.  
16. Reconnect the fan leads to the Input  
Board. Be sure that leads are  
connected to their original positions.  
17. Replace the case wraparound.  
12. After replacement of the Input  
Board, replace the four nuts and  
washers previously removed  
from the corners of the board.  
Do Not Over tighten.  
18. Replace the plastic nut from around the  
pressure regulator. Do Not Over  
tighten.  
19. Replace the carry handle.  
13. Using a 7 mm nut driver replace  
two leads originating from the  
Input Switch. (A+B)  
14. Reconnect four leads in their  
correct positions. (AC and CP)  
PRO-CUT 25  
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F-38  
F-38  
NOTES  
PRO-CUT 25  
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F-39  
F-39  
TROUBLESHOOTING & REPAIR  
MAIN INVERTER BOARD REMOVAL AND REPLACEMENT  
WARNING  
Service and repair should be performed by only Lincoln Electric factory trained personnel.  
Unauthorized repairs performed on this equipment may result in danger to the technician or  
machine operator and will invalidate your factory warranty. For your safety and to avoid  
electrical shock, please observe all safety notes and precautions detailed throughout this  
manual.  
If for any reason you do not understand the test procedures or are unable to perform the  
test/repairs safely, contact the Lincoln Electric Service Department for electrical  
troubleshooting assistance before you proceed. Call 1-888-935-3877.  
DESCRIPTION  
The following procedure will aid the technician in removing the MAIN INVERTER BOARD for  
maintenance or replacement.  
MATERIALS NEEDED  
4mm Allen Wrench  
Crescent Wrench  
7mm Nut Driver  
Needle Nose Pliers  
PRO-CUT 25  
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F-40  
F-40  
TROUBLESHOOTING & REPAIR  
MAIN INVERTER BOARD REMOVAL & REPLACEMENT (continued)  
FIGURE F.18 – MAIN INVERTER BOARD REMOVAL  
ON  
P
O
W
E
R
G
A
S
P
R
E
S
S
U
R
E
T
H
E
R
M
A
L
S
A
F
E
!
PURGE  
T
Y
OFF  
20  
15  
LINCOLN  
ELECTRIC  
12  
RE  
Q
25  
U
IR  
R
E
S
E
20  
30  
Q
U
A
/1  
15V  
IR  
E
S
A/1  
B
B
R
A
15  
N
N
V
C
H
R
C
C
IR  
A
C
C
C
U
H
IT  
IR  
U
IT  
PR  
O-CUT 25  
Main Board  
PROCEDURE  
6.  
7.  
8.  
Locate the Main Board, all associated  
leads and plug connections.  
1.  
Remove input power to PRO-CUT 25.  
2.  
3.  
Remove carrying handle using a  
4mm allen wrench.  
Label the leads and note their positions  
for reassembly.  
Using a crescent wrench,  
Using a 7mm Nut driver, remove the  
four nuts and washers located at the  
corners of the main board. (This will  
allow you to gently manipulate the board  
for labeling and removal of all Leads.)  
carefully remove the plastic nut from  
around the pressure regulator located  
on the top of the machine.  
4.  
5.  
Using a 7mm nut driver, remove  
the case wraparound.  
9.  
Remove the two harness plugs from  
front top corner of board. Label  
Perform Capacitor Discharge  
and remove the four single leads from  
the rear top corner of board. Carefully  
remove NZL, WRK, and EL leads from  
lower front of board. Also remove  
harness plug (J1). See Figure F.19.  
Procedure.  
CAUTION  
Be sure to follow the recommended static-free  
methods for handling printed circuit boards.  
Failure to do so can result in permanent damage  
to the equipment.  
10.  
Remove board.  
PRO-CUT 25  
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F-41  
F-41  
TROUBLESHOOTING & REPAIR  
MAIN INVERTER BOARD REMOVAL & REPLACEMENT (continued)  
FIGURE F.19 – INVERTER BOARD LEAD LOCATIONS  
Lead  
Leads  
Harness plugs  
NZL  
WRK  
EL  
Harness  
Plug (J1)  
14.  
15.  
Replace the plastic nut from around the  
pressure regulator. Do Not Over  
tighten.  
11.  
12.  
Reconnect all leads to the new board.  
Replace the four bolts and washers  
previously removed from the corners of  
the board.  
Replace the carry handle.  
13.  
Replace the case wraparound.  
PRO-CUT 25  
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F-42  
F-42  
NOTES  
PRO-CUT 25  
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F-43  
F-43  
TROUBLESHOOTING & REPAIR  
SWITCH  
REMOVAL AND REPLACEMENT  
WARNING  
Service and repair should be performed by only Lincoln Electric factory trained personnel.  
Unauthorized repairs performed on this equipment may result in danger to the technician or  
machine operator and will invalidate your factory warranty. For your safety and to avoid  
electrical shock, please observe all safety notes and precautions detailed throughout this  
manual.  
If for any reason you do not understand the test procedures or are unable to perform the  
test/repairs safely, contact the Lincoln Electric Service Department for electrical  
troubleshooting assistance before you proceed. Call 1-888-935-3877.  
DESCRIPTION  
The following procedure will aid the technician in removing the SWITCH for maintenance or  
replacement.  
MATERIALS NEEDED  
4 mm Allen Wrench  
Crescent Wrench  
7 mm Nut Driver  
Phillips Head Screwdriver  
Flat Head Screwdriver  
PRO-CUT 25  
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F-44  
F-44  
TROUBLESHOOTING & REPAIR  
SWITCH  
REMOVAL AND REPLACEMENT (continued)  
FIGURE F.20 – SWITCH  
Switch  
P
O
O
W
E
N
R
G
A
S
P
R
E
S
S
U
R
E
T
H
E
R
M
A
L
O
S
0
A
FF  
F
PU  
E
!
T
Y
R
G
E
2
1
5
L
IN  
C
E
O
L
L
E
C
T
N
R
IC  
2
5
R
E
Q
U
IR  
E
S
R
2
0
E
A
/1  
Q
U
1
5
IR  
E
V
S
B
R
3
A
N
0
A
PR  
O-CUT 25  
/1  
C
H
1
5
C
V
B
IR  
C
R
A
U
IT  
N
C
H
C
IR  
CU  
IT  
PROCEDURE  
7.  
8.  
Carefully remove the power switch  
assembly from the front of the machine,  
making note of insulation positioning.  
1.  
Remove input power to PRO-CUT 25.  
2.  
3.  
Remove carrying handle using a  
4mm allen wrench.  
Carefully label and identify the four leads  
and their terminals before removing.  
These leads and their positions are not  
labeled for you, so be sure to label them  
accurately  
Using a crescent wrench,  
carefully remove the plastic nut from  
around the pressure regulator located  
on the top of the machine.  
9.  
After labeling the four leads, remove them  
from the switch using a flathead  
screwdriver.  
4.  
5.  
6.  
Using a 7mm nut driver, remove  
the case wraparound.  
10.  
After replacement of the switch,  
Perform Capacitor Discharge  
Procedure.  
reconnect the four leads making sure that  
the switch is oriented correctly and the  
insulation is positioned correctly.  
Using a phillips head screwdriver, remove  
the two power switch mounting screws  
located directly above and below the  
power switch.  
11.  
12.  
Replace the case wraparound  
Replace the plastic nut from around the  
pressure regulator. Do Not Over tighten.  
13.  
Replace the carry handle  
PRO-CUT 25  
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F-45  
F-45  
TROUBLESHOOTING & REPAIR  
FAN REMOVAL AND REPLACEMENT  
WARNING  
Service and repair should be performed by only Lincoln Electric factory trained personnel.  
Unauthorized repairs performed on this equipment may result in danger to the technician or  
machine operator and will invalidate your factory warranty. For your safety and to avoid  
electrical shock, please observe all safety notes and precautions detailed throughout this  
manual.  
If for any reason you do not understand the test procedures or are unable to perform the  
test/repairs safely, contact the Lincoln Electric Service Department for electrical  
troubleshooting assistance before you proceed. Call 1-888-935-3877.  
DESCRIPTION  
The following procedure will aid the technician in removing the fan for maintenance or  
replacement.  
MATERIALS NEEDED  
4mm Allen Wrench  
Crescent Wrench  
7mm Nut Driver  
Phillips Head Screwdriver  
PRO-CUT 25  
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F-46  
F-46  
TROUBLESHOOTING & REPAIR  
FAN REMOVAL AND REPLACEMENT (continued)  
PROCEDURE  
4.  
5.  
6.  
Using a 7mm nut driver, remove  
the case wraparound.  
1.  
Remove input power to PRO-CUT 25.  
2.  
Remove carrying handle using a  
4mm allen wrench.  
Perform Capacitor Discharge  
Procedure.  
3.  
Using a crescent wrench, carefully  
remove the plastic nut from around the  
pressure regulator located on the top of  
the machine.  
Label and remove the two leads  
connected to the top of the fan. Be  
sure to correctly label these leads and  
note their positions.  
FIGURE F.21 – FAN LOCATION  
Fan  
O
P
O
N
W
E
R
G
A
S
P
R
E
S
S
U
R
E
T
H
E
R
M
A
L
S
A
PU  
F
O
E
FF  
T
R
Y
G
E
!
2
0
1
5
L
IN  
C
E
O
L
L
E
12  
N
C
T
R
IC  
R
E
2
5
Q
U
IR  
R
E
E
E
S
Q
2
0
U
IR  
A
/1  
S
1
5
V
3
0
B
R
A
/1  
A
N
1
5
C
H
V
B
R
C
C
A
IR  
N
C
C
C
H
U
IT  
IT  
IR  
U
PR  
O-CUT 25  
PRO-CUT 25  
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F-47  
F-47  
TROUBLESHOOTING & REPAIR  
FAN REMOVAL AND REPLACEMENT (continued)  
7.  
Using a phillips head screwdriver,  
remove the four mounting screws on  
the four corners of the fan. The fan  
will become free.  
8.  
9.  
After replacement of the fan, replace  
the four mounting screws located at  
the corners of the fan.  
Reconnect labeled leads to the  
top of the fan. Be sure to replace  
leads in their proper positions.  
10.  
11.  
Replace the case wraparound.  
Replace the plastic nut from around the  
pressure regulator.  
Do Not Over tighten.  
12.  
Replace the carry handle.  
PRO-CUT 25  
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F-48  
F-48  
TROUBLESHOOTING & REPAIR  
RETEST AFTER REPAIR  
Should a machine under test be rejected for any reason requiring the removal of any mechanical part that could  
affect the machine’s electrical characteristics, or if any electrical components are repaired or replaced, the  
machine must be retested.  
Machine Input and Output  
Input Volts/Hertz  
Input Current  
Rated Output  
230/1/60HZ  
15 Amps  
20A @ 100% Duty Cycle  
Output Current Range  
12 - 25 Amps  
Maximum Open Circuit Voltage  
Pilot Current  
400 Volts  
12 amps  
Functional Test  
1. Connect the machine to 230VAC and an air supply (70psi minimum).  
2. Turn on the machine and verify the following:  
- When the machine is turned on the Thermal LED turns on for approximately 1 second.  
- The fan is functional.  
- The power LED is lit.  
3. Test the pressure switch in the following way:  
- Press and hold the Purge button on the front of the machine. Using the regulator on the machine,  
slowly lower the air pressure and verify that the gas pressure LED turns on at approximately 35 to  
40 psi.  
- With the gas pressure LED on, release the Purge button and then pull the trigger on the torch.  
Verify that a pilot arc does NOT occur. Release the trigger.  
- While again pressing the Purge button, slowly increase the air pressure using the regulator on the  
machine until the gas pressure LED turns off. Verify that the LED turns off at approximately 40-45  
psi.  
- Continue to press the Purge button and set the air pressure at 65psi. Release the Purge button.  
4. Test the Purge button safety function by again pressing the Purge button and then pulling the trigger on the  
torch. Verify that a pilot arc does NOT occur. Release the trigger and the Purge button. (This is not a  
repeat of the previous step, in this step the Purge button is pressed and the gas pressure LED is off.)  
5. With no air flowing (postflow), pull the trigger on the torch. Verify that the air flows for 2 seconds (preflow)  
and then the pilot arc is initiated. While continuing to hold the trigger, verify that the pilot arc remains lit for  
3 seconds then turns off automatically. Release the trigger and verify that the air continues to flow for 10  
seconds (postflow).  
6. Remove the shield cup from the torch and verify that the safety LED turns on. Re-tighten the shield cup on  
the torch and verify that the safety LED remains lit. Pull the trigger of the torch and verify that a pilot arc  
does NOT occur. Turn the machine off and then back on to clear the safety error.  
7. Turn the PRO-CUT 25 off.  
PRO-CUT 25  
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G-1  
G-1  
ELECTRICAL DIAGRAMS  
TABLE OF CONTENTS  
-ELECTRICAL DIAGRAMS SECTION-  
ELECTRICAL DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SECTION G  
WIRING DIAGRAM - PROCUT 25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G-2  
WIRING DIAGRAM W/ADDITIONAL INFO - PROCUT 25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G-3  
SCHEMATIC - CONTROL PRINTED CIRCUIT BOARD - SHEET 1 . . . . . . . . . . . . . . . . . . . . . . G-4  
SCHEMATIC - CONTROL PRINTED CIRCUIT BOARD - SHEET 2 . . . . . . . . . . . . . . . . . . . . . . G-5  
SCHEMATIC - CONTROL PRINTED CIRCUIT BOARD - SHEET 3 . . . . . . . . . . . . . . . . . . . . . . G-6  
PC BOARD ASSEMBLY - MAIN INVERTER BOARD. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G-7  
PC BOARD ASSEMBLY - INPUT BOARD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G-8  
PC 25 TORCH DETAILS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G-9  
PRO-CUT 25  
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G-2  
G-2  
ELECTRICAL DIAGRAMS  
WIRING DIAGRAM - PRO-CUT 25  
WORK CLAMP  
Q1a,b,c  
IRG4BC30W  
Lout  
D10  
BS1  
WRK  
C26  
240uH  
8A  
SW1  
AC  
AC  
RL2  
RL2  
RL2  
L1  
RL3  
A
B
T2  
+12VDC TRANSFER  
PRI  
SEC  
D11  
300uH  
R1  
+
CP  
CP  
CP  
CP  
R1  
CP  
CP  
10/10W  
C1a,b  
RL1  
NZL (2)  
C12  
+
R2  
AC  
AC  
C14  
C2a,b  
R24  
RL1  
RL2  
6.8k/5W  
V1  
V2  
Q2a,b,c  
IRG4BC30W  
115VAC  
L1  
SHUNT  
EL (3)  
T1  
C13  
SH+  
SH-  
230V  
115V  
RL1  
CN1  
CN2  
9
10  
5
6
3
22  
2
PT  
CN3  
15VAC  
15VAC  
1
2
3
4
5
6
7
8
1
2
3
4
SAFETY  
+28VDC  
SEC GND  
OVLOAD  
115/230  
+12VDC  
L1  
12VDC  
Main Inverter Board  
Soleno  
id 2  
Input  
20  
CN1  
Voltage Board  
15 16 12 18 14 1 11 4 13 7 19 24 21 23 8 17  
1
2
3
4
8
6 17 9  
3
1
2 18 14 7 15 4 11 5 16 10 12 13  
23 22 24  
CN1  
12VDC  
Display LED's  
Air  
Purge  
Switch  
Solenoid  
1
Output Control  
Control Board  
NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual. The wiring diagram specific to your code is pasted inside one of the enclosure panels of your machine.  
PRO-CUT 25  
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G-3  
G-3  
ELECTRICAL DIAGRAMS  
WIRING DIAGRAM W/ADDITIONAL INFO  
Reed switch (BS1)  
closes when cutting  
current is drawn  
All thermo devices are on this  
inverter board  
Typical input current draw:  
115v 25A/35% = 37.7A  
20A/60% = 26.7A  
file: procut25.pp  
PRO CUT 25  
3-11-02  
3-20-02  
3-6-03  
+ 12 from Control bd  
.
Soft start relay  
3 to 5 sec delay  
Choke Thermo ( PCT)  
T3 (N.O.)  
230v 25A/60% = 19A  
20A/100%=15A  
operating freq. 63 khz / 100khz  
Soft start resistor  
P
( over heats on 208 input !)  
(12 vdc  
)
(PC 25) / (PC20)  
RL3  
Listen for relay to click in  
Auto Reconnect Feature  
Shown in 230  
de-energized  
sec  
Cuts for 3 sec then quits  
(stuck in pilot mode )  
or  
CUTTING  
after a 3 sec delay  
primary c.t.  
To  
Main  
thermo  
PT2  
4.7nf  
Caps.  
pwm  
chip  
pilot current is 1/2 of  
cutting current  
4kv  
*does it work  
in the other input  
(N.C.)  
PILOT  
Current  
11w5hveancin 115  
is 12 amps  
voltage 115v or 230 v ?  
If it does, it is an  
To Control bd  
.
2
f
+12V_sw  
400Vocv  
400v  
PILOT  
PIP  
300VDC  
Aux  
fuse  
100v pilot &cutting  
input bd  
.
25a @ 35% duty (115 input)  
25a @ 60% duty (230 input)  
F.e.t.  
230vac  
thermo  
PT1  
RL1  
cutting  
115vac  
when in 230  
12 to 25 amps range  
when in 115  
2.2 f/400v  
3/8 max thickness @ 30 amp input  
(N.C.)  
Transfer relay  
(signal from  
control bd.)  
Must be within  
some ‘s  
ac  
On for 110v  
Reconnect  
main relay  
+/- 10% of input.  
shown in pilot  
Must be greater than 208v.  
“see” pip ckt  
inset detail  
This is the voltage  
reconnect for 110V  
Must be  
a
primary current  
operation  
PC 25 nozzle!  
S22147-028  
YES for Ranger 250 series  
Commander 300, 400 ,500’s  
CUTTING PATH  
feedback c.t.  
(voltage doubler  
)
PWM  
driver  
card  
Auto  
reconnect  
card  
no drag cups either  
try without.  
!
PILOT PATH  
PIP PATH  
+20 Vdc for NO parts in place(pip)  
+6 Vdc with parts IN  
Must be to within  
50hz /60 hz  
4.7  
f
1/8 ” to transfer to cut.  
4kv  
RPM’s 2700/ 3100  
+15Vrms  
reg  
+12 vdc  
Trigger:  
amps .13 / .12  
runs all the time  
8v when open  
Must double hit  
Supply for torch,&  
main air solenoid .  
pink  
pink  
PWM  
card  
when first turned on  
input ( safety feature)  
or after thermo reset  
DC  
amp  
isolated  
OVL signal  
common for  
trigger  
{
shunt input  
12 V regulator  
on inverter bd  
.
+12V  
inverter bd  
.
to  
nozzle ckt  
not so in preflow  
.
.
Pcb  
.
PIP supply 20 vac  
{
Represents:  
+8 = on (from  
EV2  
direct to control bd..  
Q4  
board soldered to  
+12V  
torches of  
over  
Vs =OK  
0v= over  
inverter bd.  
a mother bd  
.
+8V  
card  
volts  
15 or 25 ft are ok  
REF bd  
card  
{
signal  
load.  
choke  
Reconnect  
RL1  
+15Vrms  
Auto reconnect  
PT3  
+12V  
pilot relay  
+12 v  
ckt  
.
{
Torch solenoid:  
supply from inverter bd  
.
Represents:  
relay  
Control is from control bd  
.
relay soldered to  
a mother bd  
.
45 to 55 ohms  
Schematic 98044  
+8v = open trigger to  
12v=230  
0v =115  
Schematic 98056 (SIPC 25)  
Scaled  
down  
version  
of  
{
+8v = no output  
6v = output  
***Detail***  
PIP (safety ckt.)  
To  
output  
V= ok  
0v = overload  
8
vdc  
(choke thermo or input bd.)  
Input bd  
20 vac  
Inverter bd  
{
CN1-4  
+8  
CN2-6  
+12v =pilot  
0 = cutting  
when  
open  
NZL  
To  
+12  
CN2-11  
CN1-3  
EL  
for  
correct  
pressure  
all ckt. commons  
13  
CN1-7  
+12v = sol off  
0v = sol on  
CN1-3  
+20 Vdc for NO parts  
in place(pip)  
10 K  
+6 Vdc with parts IN  
LED  
ckt.  
8vdc @ min  
+12V_sw  
+8  
vdc  
Set air pressure while in  
“see” pip ckt  
inset detail  
10-5 vdc @ max.  
(power supplies from  
inverter bd.  
8V  
reg  
purge to 65 psi  
.
Control bd  
.
Ckt.  
“see” pip ckt  
Ckt.  
pressure  
inset detail  
65  
Display bd & Driver bd  
.
for pot only!!)  
2 . 5  
K
50  
150  
170  
Closes @ 43.5 psi (3bars)  
Opens@ 37.7 to 42 psi  
(2.6 to 2.9 bars)  
Input Power  
Thermo  
input overload  
Gas Psi  
.
Safety led  
indicates that  
(pip)  
also  
comes on if  
0
the +12 on inverter bd  
reset by turning off PC25  
(control bd mounted)  
+12 VDC sw supply is used for:  
1. Output control (control).  
& its ref bd. (invert)  
+8 VDC supply is used for:  
1. Turn on PWM (invert)  
2. PIP detect ckt.(control)  
3. Pilot arc timer (control)  
no gas psi  
.
is up ( not the +8)  
Air Guage  
8vdc  
2. Shunt feedback ( invert)  
all LED’s come on initally  
comes “on” at turn on  
for 3 sec.  
Supply pressure must be:  
80 to 150 psi with a flow  
rate of no less than 4.0 cfm(113 l/min.)  
240 cfh  
3. Transfer relay (invert & control) 4. Purge ckt button(control)  
This bd generates 8 vdc  
which get its input from  
the inverter bd. via the  
12 vdc on the inverter bd  
8v is used on both bds.  
then just the POWER led is lit  
THERMO led stays lit for  
approx 3 sec also at turn on.  
4. Torch solenoid (inv & control) 5. Drivers for LED logic (control)  
Purge Switch (n.o.)  
5. LED supply  
6. Torch solenoid logic ckt(control)  
7. Air solenoid logic ckts & driver (control)  
8. Transfer relay (invert) Logic &driver(control)  
.
Schematic 99016 ( SPA25)  
NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual.  
PRO-CUT 25  
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G-4  
G-4  
ELECTRICAL DIAGRAMS  
SCHEMATIC- CONTROL PRINTED CIRCUIT BOARD - SHEET 1  
NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual.  
PRO-CUT 25  
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G-5  
G-5  
ELECTRICAL DIAGRAMS  
SCHEMATIC- CONTROL PRINTED CIRCUIT BOARD - SHEET 2  
NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual.  
PRO-CUT 25  
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G-6  
G-6  
ELECTRICAL DIAGRAMS  
SCHEMATIC- CONTROL PRINTED CIRCUIT BOARD - SHEET 3  
NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual.  
PRO-CUT 25  
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G-7  
G-7  
ELECTRICAL DIAGRAMS  
PC BOARD ASSEMBLY - MAIN INVERTER BOARD  
NOTE: Lincoln Electric assumes no responsibility for liablilities resulting from board level troubleshooting. PC Board repairs will invalidate your factory warranty. Individual Printed Circuit Board Components are not available from Lincoln Electric. This information is pro-  
vided for reference only. Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in danger to the Machine Operator or Technician. Improper PC board repairs could result in damage to the  
machine.  
PRO-CUT 25  
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G-8  
G-8  
ELECTRICAL DIAGRAMS  
PC BOARD ASSEMBLY - INPUT BOARD  
NOTE: Lincoln Electric assumes no responsibility for liablilities resulting from board level troubleshooting. PC Board repairs will invalidate your factory warranty. Individual Printed Circuit Board Components are not available from Lincoln Electric. This information is pro-  
vided for reference only. Lincoln Electric discourages board level troubleshooting and repair since it may compromise the quality of the design and may result in danger to the Machine Operator or Technician. Improper PC board repairs could result in damage to the  
machine.  
PRO-CUT 25  
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G-9  
G-9  
ELECTRICAL DIAGRAMS  
PC 25 TORCH DETAILS  
%= AIR FLOW  
Spring is relaxed  
helping the push  
75%  
ELECTRODE  
BRASS CONDUCTOR  
WITH A VENT  
20%  
VENT  
5%  
NOZZLE  
VERY LITTLE  
COMPRESSED  
AIR FLOWING  
at tip.  
AIR IS FLOWING &  
ELECTRODE SOL. IS “ON”.  
PILOT CURRENT PATH  
1. No Compressed air flowing  
2. Air is flowing & torch solenoid is  
AIR TUBE (COPPER)  
ELECTRODE SOL. ENERGIZED  
(surface area is great)  
Cup “O” rings must be good.  
electrode is held to the  
nozzle.  
“ON”  
HOLDS ELECTRODE TO NOZZLE  
COMPRESSED AIR  
INPUT  
CHAMBER FULL OF  
COMPRESSED AIR  
Spring is compressed  
Air pressure pushes back  
electrode creating a “LIFT”  
start feature inside the  
nozzle for a pilot arc  
work  
Air Flowing & Torch Solenoid is  
CUTTING CURRENT PATH  
“OFF”  
PILOT & CUTTING  
ELECTRODE SOL.  
DE-ENERGIZED  
through plasma arc and yellow color parts  
Lift start type feature during pilot  
COMPRESSED AIR  
INPUT  
VENT  
CURRENT PATH THROUGH TORCH  
COMPRESSED AIR FLOW  
NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual.  
PRO-CUT 25  
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SVM ERROR REPORTING FORM  
We need to know if there are errors in our manuals. We also value any suggestions as to  
additional tests or procedures that would make this SVM a better tool for you.  
If you discover new or different “Problems or Symptoms” that are not covered in the three col-  
umn troubleshooting chart, please share this information with us. Please include the  
machine’s code number and how the problem was resolved.  
Thank You,  
Technical Services Group  
Lincoln Electric Co.  
22801 St. Clair Ave.  
Cleveland, Ohio 44117-1199  
FAX 216-481-2309  
SVM Number ___________________________  
Page Number if necessary__________________  
Your Company__________________________  
Your Name_____________________________  
Please give detailed description below:  
___________________________________________________________________________  
___________________________________________________________________________  
___________________________________________________________________________  
___________________________________________________________________________  
___________________________________________________________________________  
___________________________________________________________________________  
___________________________________________________________________________  
___________________________________________________________________________  
___________________________________________________________________________  
___________________________________________________________________________  
___________________________________________________________________________  
___________________________________________________________________________  
___________________________________________________________________________  
SD287 04/06  
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