Lincoln Electric INVERTEC V145-S User manual

12/2005
Rev. 01
INVERTECV145-S
SERVICE MANUAL
LINCOLN ELECTRIC ITALIA S.r.l
Via Fratelli Canepa 8, 16010 Serrà Riccò (GE), Italia
www.lincolnelectriceurope.com

2
Safety 11/04
WARNING
This equipment must be used by qualified personnel. Be sure that all installation, operation, maintenance and repair
procedures are performed only by qualified person. Read and understand this manual before operating this equipment.
Failure to follow the instructions in this manual could cause serious personal injury, loss of life, or damage to this
equipment. Read and understand the following explanations of the warning symbols. Lincoln Electric is not responsible
for damages caused by improper installation, improper care or abnormal operation.
WARNING: This symbol indicates that instructions must be followed to avoid serious personal injury,
loss of life, or damage to this equipment. Protect yourself and others from possible serious injury or
death.
READ AND UNDERSTAND INSTRUCTIONS: Read and understand this manual before operating
this equipment. Arc welding can be hazardous. Failure to follow the instructions in this manual could
cause serious personal injury, loss of life, or damage to this equipment.
ELECTRIC SHOCK CAN KILL: Welding equipment generates high voltages. Do not touch the
electrode, work clamp, or connected work pieces when this equipment is on. Insulate yourself from
the electrode, work clamp, and connected work pieces.
ELECTRICALLY POWERED EQUIPMENT: Turn off input power using the disconnect switch at the
fuse box before working on this equipment. Ground this equipment in accordance with local electrical
regulations.
ELECTRICALLY POWERED EQUIPMENT: Regularly inspect the input, electrode, and work clamp
cables. If any insulation damage exists replace the cable immediately. Do not place the electrode
holder directly on the welding table or any other surface in contact with the work clamp to avoid the
risk of accidental arc ignition.
ELECTRIC AND MAGNETIC FIELDS MAY BE DANGEROUS: Electric current flowing through any
conductor creates electric and magnetic fields (EMF). EMF fields may interfere with some
pacemakers, and welders having a pacemaker shall consult their physician before operating this
equipment.
CE COMPLIANCE: This equipment complies with the European Community Directives.
FUMES AND GASES CAN BE DANGEROUS: Welding may produce fumes and gases hazardous to
health. Avoid breathing these fumes and gases. To avoid these dangers the operator must use
enough ventilation or exhaust to keep fumes and gases away from the breathing zone.
ARC RAYS CAN BURN: Use a shield with the proper filter and cover plates to protect your eyes from
sparks and the rays of the arc when welding or observing. Use suitable clothing made from durable
flame-resistant material to protect you skin and that of your helpers. Protect other nearby personnel
with suitable, non-flammable screening and warn them not to watch the arc nor expose themselves to
the arc.
WELDING SPARKS CAN CAUSE FIRE OR EXPLOSION: Remove fire hazards from the welding
area and have a fire extinguisher readily available. Welding sparks and hot materials from the welding
process can easily go through small cracks and openings to adjacent areas. Do not weld on any
tanks, drums, containers, or material until the proper steps have been taken to insure that no
flammable or toxic vapors will be present. Never operate this equipment when flammable gases,
vapors or liquid combustibles are present.
WELDED MATERIALS CAN BURN: Welding generates a large amount of heat. Hot surfaces and
materials in work area can cause serious burns. Use gloves and pliers when touching or moving
materials in the work area.
SAFETY MARK: This equipment is suitable for supplying power for welding operations carried out in
an environment with increased hazard of electric shock.

3
CYLINDER MAY EXPLODE IF DAMAGED: Use only compressed gas cylinders containing the
correct shielding gas for the process used and properly operating regulators designed for the gas and
pressure used. Always keep cylinders in an upright position securely chained to a fixed support. Do
not move or transport gas cylinders with the protection cap removed. Do not allow the electrode,
electrode holder, work clamp or any other electrically live part to touch a gas cylinder. Gas cylinders
must be located away from areas where they may be subjected to physical damage or the welding
process including sparks and heat sources.

4
Electromagnetic Compatibility (EMC) 11/04
This machine has been designed in accordance with all relevant directives and standards. However, it may still generate
electromagnetic disturbances that can affect other systems like telecommunications (telephone, radio, and television) or
other safety systems. These disturbances can cause safety problems in the affected systems. Read and understand
this section to eliminate or reduce the amount of electromagnetic disturbance generated by this machine.
This machine has been designed to operate in an industrial area. To operate in a domestic area it is
necessary to observe particular precautions to eliminate possible electromagnetic disturbances. The
operator must install and operate this equipment as described in this manual. If any electromagnetic
disturbances are detected the operator must put in place corrective actions to eliminate these disturbances
with, if necessary, assistance from Lincoln Electric.
Before installing the machine, the operator must check the work area for any devices that may malfunction because of
electromagnetic disturbances. Consider the following.
•Input and output cables, control cables, and telephone cables that are in or adjacent to the work area and the
machine.
•Radio and/or television transmitters and receivers. Computers or computer controlled equipment.
•Safety and control equipment for industrial processes. Equipment for calibration and measurement.
•Personal medical devices like pacemakers and hearing aids.
•Check the electromagnetic immunity for equipment operating in or near the work area. The operator must be sure
that all equipment in the area is compatible. This may require additional protection measures.
•The dimensions of the work area to consider will depend on the construction of the area and other activities that are
taking place.
Consider the following guidelines to reduce electromagnetic emissions from the machine.
•Connect the machine to the input supply according to this manual. If disturbances occur if may be necessary to take
additional precautions such as filtering the input supply.
•The output cables should be kept as short as possible and should be positioned together. If possible connect the
work piece to ground in order to reduce the electromagnetic emissions. The operator must check that connecting
the work piece to ground does not cause problems or unsafe operating conditions for personnel and equipment.
•Shielding of cables in the work area can reduce electromagnetic emissions. This may be necessary for special
applications.

5
INDEX
Technical specification…………………………………………………………………………………………6
Installation and Operator Instructions………………………………………………………………………..7
Accessories…………………………………………………………………………………………………… 9
Maintenance……………………………………………………………………………………………………10
Major Component Location.…………………………………………………………………………………..12
Theory of Operation……………………………………………………………………………………………13
Troubleshooting and Repair…………………………………………………………………………………..20
Spare Parts 34
Electrical Diagram … ………………………………………………………………………………36
Electrical Diagram reference 37

6
Technical Specifications - V145S
INPUT
Input Voltage
230 V ±15%
Single Phase
Input Power at Rated Output
3.0 kW @ 100% Duty Cycle
4.4 kW @ 35% Duty Cycle
Frequency
50/60 Hertz (Hz)
RATED OUTPUT
Duty Cycle
(Based on a 10 min. period @ 40°C)
100%
35%
(Based on a 10 min. period @ 20°C)
100%
60%
Output Current
105 A
145 A
120 A
145 A
Output Voltage
24.2 Vdc
25.8 Vdc
24.8 Vdc
25.8 Vdc
OUTPUT RANGE
Welding Current Range
5 -145 Amps
Maximum Open Circuit Voltage
75 Vdc (CE model)
12 Vdc (CE 12V model)
12 Vdc (AUSTRALIA model)
RECOMMENDED INPUT CABLE AND FUSE SIZES
Fuse (delayed) or
Circuit Breaker (“D” characteristic) Size
16 A
Type of Plug
SCHUKO 16 A / 250 V or
AUSTRALIAN 15 A / 250 V
(Included with Machine)
Input Power Cable
3 Conductor, 2.5 mm2
PHYSICAL DIMENSIONS
Height
288 mm Width 158 mm Length 392 mm
Weight
5.9 kg
6.4 kg (CE 12V model)
Operating Temperature
-10°C to +40°C Storage Temperature -25°C to +55°C

7
Installation and Operator Instructions
Read this entire section before installation or operation
of the machine.
Location and Environment
This machine can operate in harsh environments.
However, it is important that simple preventative
measures are followed to assure long life and reliable
operation:
•Do not place or operate this machine on a surface
with an incline greater than 15° from horizontal.
•Do not use this machine for pipe thawing.
•This machine must be located where there is free
circulation of clean air without restrictions for air
movement to and from the air vents. Do not cover
the machine with paper, cloth or rags when
switched on.
•Dirt and dust that can be drawn into the machine
should be kept to a minimum.
•This machine has a protection rating of IP23. Keep
it dry when possible and do not place it on wet
ground or in puddles.
•Locate the machine away from radio controlled
machinery. Normal operation may adversely affect
the operation of nearby radio controlled machinery,
which may result in injury or equipment damage.
Read the section on electromagnetic compatibility in
this manual.
•Do not operate in areas with an ambient
temperature greater than 40°C.
Duty Cycle
The duty cycle of a welding machine is the percentage of
time in a 10 minute cycle at which the welder can
operate the machine at rated welding current.
Example: 35% duty cycle:
Welding for 3.5 minutes. Break for 6.5 minutes.
Refer to the Technical Specification section for more
information about the machine rated duty cycles.
Input Supply Connection
Check the input voltage, phase, and frequency supplied
to this machine before turning it on. The allowable input
voltage is indicated in the technical specification section
of this manual and on the rating plate of the machine.
Be sure that the machine is grounded.
Make sure the amount of power available from the input
connection is adequate for normal operation of the
machine. The fuse rating and cable sizes are both
indicated in the technical specification section of this
manual.
This machine is designed to operate on engine driven
generators as long as the 230Vac auxiliary can supply
adequate power as indicated in the technical
specification section of this manual. The auxiliary supply
of the generator must also meet the following conditions:
•Vac peak voltage: below 410V.
•Vac frequency: in the range of 50 and 60 Hertz.
•RMS voltage of the AC waveform: 230Vac ± 15%.
It is important to check these conditions because many
engine driven generators produce high voltage spikes.
Operation of this machine with engine driven generators
not conforming to these conditions is not recommended
and may damage the machine.
Output Connections
A quick disconnect system using Twist-MateTM cable
plugs is used for the welding cable connections. Refer
to the following sections for more information on
connecting the machine for operation of stick welding
(MMA) or TIG welding.
Stick Welding (MMA)
First determine the proper electrode polarity for the
electrode to be used. Consult the electrode data for this
information. Then connect the output cables to the
output terminals of the machine for the selected polarity.
Shown here is the connection method for DC(+) welding.
Connect the electrode
cable to the (+) terminal
and the work clamp to the
(-) terminal. Insert the
connector with the key
lining up with the keyway
and rotate approximately ¼
turn clockwise. Do not over
tighten.
For DC(-) welding, switch the cable connections at the
machine so that the electrode cable is connected to (-)
and the work clamp is connected to (+).
TIG Welding
This machine does not include a TIG torch necessary for
TIG welding, but one may be purchased separately.
Refer to the accessories section for more information.
Most TIG welding is done with DC(-) polarity shown
here. If DC(+) polarity is necessary switch the cable
connections at the machine.
Connect the torch cable to
the (-) terminal of the
machine and the work
clamp to the (+) terminal.
Insert the connector with
the key lining up with the
keyway and rotate
approximately ¼ turn
clockwise. Do not over
tighten. Finally, connect
the gas hose to the gas regulator on the cylinder of gas
to be used.
VRD: Voltage Reduction Device
This machine is provided by an internal VRD (Voltage
Reduction Device) circuitry: this device reduces the
voltage at the output leads. The VRD is automatically

8
enabled / disabled by the machine. The factory default
voltage is:
V145-S CE: 75 Vdc
V145-S CE (12V): 12 Vdc
V145-S AUSTRALIA: 12 Vdc
Refer to the section below for more details.
Auto Adaptive Arc Force (with MMA
welding)
During MMA welding is activated the function Auto
Adaptive Arc Force that increases temporary the output
current, used to clear intermittent connections between
the electrode and the weld puddle that occur during stick
welding.
This is an active control feature that guarantees the best
arrangement between the arc stability and spatter
presence. The feature "Auto Adaptive Arc Force" has
instead of a fixed or manual regulation, an automatic and
multilevel setting: its intensity depends by the output
voltage and it is calculated in real time by the
microprocessor where are also mapped the Arc Force
levels. The control measure in each instant the output
voltage, compare with the mapped levels and it
determines the amount of the peak of current to apply;
that value is enough to breaks the metal drop that is
being transferred from the electrode to the workpiece as
to guarantee the arc stability, but not too high to avoid
spatters around the welding puddle. That means:
•Electrode / workpiece sticking prevention, also with
low current values.
•Spatters reduction.
The welding operations are simplified and the welded
joins looks better, also if not brushed after the welding.
This feature is available in the Soft Stick and Crisp
Stick operating modes and can be selected by the
operator and it allows to weld with the characteristics
more suitable at the electrode type and welding
conditions. The Crisp Stick feature also increases the
Hot Start action, facilitating the arc striking.
With the MMA welding are also enabled the following
features:
•Hot Start: This is a temporary increase in the initial
welding current. This helps ignite the arc quickly
and reliably.
•Anti-Sticking: This is a function that decreases the
output current of the machine to a low level when
the operator makes an error and sticks the electrode
to the work piece. This decrease in current allows
the operator to remove the electrode from the
electrode holder without creating large sparks that
can damage the electrode holder.
Refer to the section below for more details.
Controls and Operational Features
A. Output Current
Knob:
Potentiometer used
to set the output
current used during
welding, from 5A to
145A.
B. Welding Mode
Switch: With three
positions, controls
the welding mode of
the machine: two for
Stick welding (Soft
and Crisp) and one
for Lift TIG welding.
•Soft Stick: For a welding with a low spatter
presence.
•Crisp Stick: For an aggressive welding, with an
increased Arc stability.
•Lift TIG: When the mode switch is in the Lift TIG
position, the stick welding functions are disabled
and the machine is ready for Lift TIG welding. Lift
TIG is a method of starting a TIG weld by first
pressing the TIG torch electrode on the work piece
in order to create a low current short circuit. Then,
the electrode is lifted from the work piece to start the
TIG arc.
C. Thermal LED: This indicator will turn on when the
machine is overheated and the output has been
disabled. This normally occurs when the duty cycle
of the machine has been exceeded. Leave the
machine on to allow the internal components to
cool. When the indicator turns off, normal operation
is again possible.
D. Power On/Off & VRD (Voltage Reduction Device)
LEDs: These LEDs (one green and one red)
operates as described in the table below:
LED status
Green Red Function
ON OFF The machine is turned ON.
VRD ON condition: The machine
is at idle (no-welding time) and
the VRD device is enabled. No
current at the output leads; the
voltage has reached a value
under the VRD limit.
OFF ON The machine is turned ON.
VRD OFF condition: A welding is
running and the VRD device is
disabled. Presence of current at
the output leads, the voltage
value may be over the VRD limit.
This permanent LED condition,
showed at idle (no-welding time),
indicates a machine damage.

9
OFF OFF The machine is turned OFF
and/or the input cord could be
disconnected from the mains.
ERROR condition: With the
Power Switch turned ON and the
input cord properly connected to
a “live” main supply, this LED
condition indicates a machine
damage.
ON ON ERROR condition: This LED
condition indicates a machine
damage.
E. Positive Quick Disconnect: Positive output
connector for the welding circuit.
F. Negative Quick Disconnect: Negative output
connector for the welding circuit.
G. Power Switch: It
turns ON / OFF
the input power to
the machine.
H. Input cable: This
machine is
provided with a
plugged input
cord. Connect it
to the mains.
I. Fan: This
machine has a
F.A.N. (Fan As
Needed) circuitry
inside: the fan is
automatically turned ON or OFF. This feature
reduces the amount of dirt which can be drawn
inside the machine and reduces power
consumption. The F.A.N. operates in different
modes, it depends by the machine type and by the
selected weld:
•V145-S CE (STICK mode): When the machine
is turned ON the fan will turn ON. The fan will
continue to run whenever the machine is
welding. If the machine doesn’t weld for more
than five minutes, the fan will turn OFF.
•V145-S CE (TIG mode), V145-S CE (12V) and
AUSTRALIA (STICK and TIG modes): When
the machine is turned ON the fan is OFF. The
fan will turn ON only when a weld is started and
it will continue to run whenever the machine is
welding. If the machine doesn’t weld for more
than five minutes, the fan will turn OFF.
Maintenance
WARNING
For any maintenance or repair operations it is
recommended to contact the nearest technical service
center or Lincoln Electric. Maintenance or repairs
performed by unauthorized service centers or personnel
will null and void the manufacturers warranty.
The frequency of the maintenance operations may vary
in accordance with the working environment. Any
noticeable damage should be reported immediately.
•Check cables and connections integrity. Replace, if
necessary.
•Keep clean the machine. Use a soft dry cloth to
clean the external case, especially the airflow inlet /
outlet louvers.
WARNING
Do not open this machine and do not introduce anything
into its openings. Power supply must be disconnected
from the machine before each maintenance and service.
After each repair, perform proper tests to ensure safety.
Accessories
KIT-140A-16-3M Welding kit cables (3m, 16mm2).
KIT-140A-25-5M Welding kit cables (5m, 25mm2).
W0400062A TIG torch with tap, 4m.
.
W7915000A Carrying case with accessories: Welding kit cables (3m, 16mm2), Hammer/wire brush,
Welding mask with glasses.

10
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 preventive maintenance, perform the
following capacitor discharge procedure to avoid electric
shock
INPUT FILTER CAPACITOR
DISCHARGE PROCEDURE
1. Remove input power to V145-S machine
2. Remove secondary case
3. Obtain a high resistance and high wattage resistor (
25-1000 ohms and 25 watts minimum ). This
resistor is NOT supplied with the machine. NEVER
USE A SHORTING STRAP FOR THIS
PROCEDURE.
4. Locate the two terminals DC+ and DC – on the input
board. See Figure 1
5. Use electrically insulate gloves and insulated pliers.
Hold the body of the resistor and connect the
resistor leads across the two terminals. Hold the
resistor in place for 10 seconds. DO NOT TOUCH
CAPACITOR TERMINALS WITH YOUR BARE
HANDS.
6. Check the voltage across the two terminals. Voltage
should be zero. If any voltage remains, repeat this
procedure.
Fig.1
DC -
DC +

11
ROUTINE MAINTENANCE
1. Keep the welding 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 the machine should be cleaned with
a low pressure and dry airstream. Keeping the
machine clean will result in cooler operation and
higher reliability.
3. Examine the sheet metal case for dents or
breakage. Repair the case as required. Keep the
case in good condition to insure that high voltage
parts are protected and correct spacing are
maintained. All external sheet metal screw must be
in place to ensure case strength and electrical
ground continuity.
THERMAL PROTECTION
Thermal detection device protect the machine from
excessive operating temperatures. Excessive
temperatures may be caused by a lack of cooling air or
operating the machine beyond the duty cycle and output
rating. If excessive operating temperatures should
occur, the yellow LED will light and the detection device
will prevent output voltage or current.
These detection device 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 period.
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 corrected.

12
MAJOR COMPONENTS LOCATION
ref. 03 secondary case
ref. 05 fan
ref. 09 input board
ref. 10 inverter board
ref. 11 control board

13
THEORY OF OPERATION
General description…………………………………………………………………………….14
Input Line Voltage, Auxiliary Voltage, Precharge…………………………………………….14
Inverter Board , Main Transformer, Output Rectifier and Choke……………………………..15
Control board…………………………………………………………………………….…… 16
Protection Circuits……………………………………………………………………………..17
IGBT operation……………………………………………………………………………… 18
Block diagram

14
Input Line Voltage, Auxiliary Voltage and Precharge
GENERAL DESCRIPTION
The Invertec V145-S is an inverter based welding power
sources that offers soft , crisp Stick and LIF TIG process.
INPUT LINE VOLTAGE, AUXILIARY
VOLTAGE AND PRECHARGE
The Invertec V145-S can be connected to a 230V single
phase input voltage.
This unit can be also connect to engine driven
generators but it must follow the below conditions:
•Vac peak voltage: below 410V.
•Vac frequency: in the range of 50 and 60 Hertz.
•RMS voltage of the AC waveform: 230Vac ± 15%.
The initial power is applied to the Invertec V145-S trough
a line switch located on the back of the machine. The
voltage is after rectified by the input rectifier on input
board and the resultant DC voltage is applied at inverter
Pcb’s.
During the precharge time the DC input voltage is
applied to the filter capacitors ( located on the inverter
Pcb ) through a start resistance ( located on input board)
that limits the charge current. After this time the start
relays go closed and they by-pass the start resistance (
there are two start relays in parallel , RL1A and RL2A ).
The 230AC voltage is also applied to a auxiliary voltage
circuit, that gives the necessary low voltages ( + 15V
and +5V ) for the control board.

15
Inverter board , Main transformer, Output rectifier and Output Choke
INVERTER BOARDs, MAIN
TRANSFORMER, OUTPUT RECTIFIER
AND OUTPUT CHOKE
When the input filter capacitors are fully charged they act
as power supplies for the IGBT switching circuit.
The IGBTs supply the main transformer winding with
80KHz current flow.
The inverter board also monitors the filter capacitors for
overvoltage. If this occurs, the appropriate error signal is
sent to the control board to disable the machines output
and to turn on the thermal/voltage Overload LED.
The IGBTs act as a switch assembly. This assembly
feeds the primary winding of the main transformer. When
current is pulsed through this primary winding, a
resultant current is produced on a secondary winding of
the main transformer. The DC current flow through the
primary winding is redirected back to the filter capacitors
when the IGBTs are turned off. This is due to the
inductance of the transformer primary winding.
The secondary winding supplies the electrode-to-work
voltages and the resulting current.
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 output rectifier receives the AC output from the main
transformer secondary winding and rectifies it to a DC
voltage level. Since the output choke is in series with the
positive leg of the output rectifier.
A filtered DC output is applied to the machine’s output
terminals.

16
Control board
Control Board
The control board receives status and
analogue feedback from the inverter board,
input board and various sensor.
The control circuitry interprets these signals,
makes decisions and changes the machine
mode and output to satisfy the requirements
as defined by the circuitry.
The control board sends a signals to the
inverter boards to control the output current.
This machine is provided by an internal VRD (Voltage
Reduction Device) circuitry: this device reduces the
voltage at the output leads. The VRD is automatically
enabled / disabled by the machine. The factory default
voltage is:
for V145-S CE: 75 Vdc
for V145-S CE (12V): 12 Vdc
forV145-S AUSTRALIA: 12 Vdc
For CE version,ONLY: After 5 minutes of inactivity
the OCV shut down from 75Vdc to around 12Vdc
On control board DIP SWITCHES are present for these
above settings, see pag.33

17
OVERLOAD PROTECTION
The Invertec V145-S is electrically protected from
producing higher than normal output currents. An
electronic protection circuit limits the current to within the
capabilities of the machine.
THERMAL PROTECTION
There are one thermal device located on the output
diodes heatsink;it protect the machine from excessive
operating temperature.
Excessive temperature may be caused by a lack of
cooling air or by operating the machine beyond the duty
cycle and output rating. If excessive operating
temperature should occur, the Thermal LED indicator on
the control board, will turn ON and the thermostat will
prevent output current.
The thermal protection device is self-resetting once the
machine cools sufficiently. If the shut down 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 about 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.

18
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 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.
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.

19
TROUBLESHOOTING AND REPAIR SECTION
How to use troubleshooting Guide……………………………………………………………. 20
Input Filter Capacitors discharge procedure………………………………………………….. 21
Troubleshooting Guide………………………………………………………………………… 22
Input Board Resistance Test………………………………………………………………….. 23
Inverter Board Resistence Test……………………………………………………………….. 25
Input Board Voltage Test……………………………………………………………………... 29
Inverter Board Voltage Test……………………………………………………………………..31
Control Board …...………………………………………….33

20
HOW TO USE TROUBLESHOOTING GUIDE
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 1. LOCATE PROBLEM (SYMPTOM).
Look under the column labeled “PROBLEMS”.
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.
Step 2. PERFORM EXTERNAL TESTS.
The second column, labeled “CHECKS”, 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.
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.
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 Wiring Diagrams Section Table of
Contents to locate the appropriate diagram.