TROUBLESHOOTING WELDSKILL 250, 350
Manual 0-5186 6-15
Troubleshooting
Once power is applied to the Power Source, there are extremely hazardous voltage and power levels present.
Do not touch any live parts.
4 Power Source or Wirefeeder Faults
The following table is a guide for analyzing problems and making repairs to the Power Source and/or Wirefeeder.
Fault Possible Cause Remedy
1 The wirefeed motor
and the contactor do
not operate when the
torch trigger switch is
depressed.
A The 20V AC supply control voltage
from the auxiliary transformer is
not connected to the Control PCB.
A Check for 20 on PCB at pins
CN3/1 & CN3/3. Repair fault.
B The thermostat contacts are
open circuit or the wires to the
thermostat are broken.
B Replace the thermostat or
repair the thermostat wires.
C Bad electrical connection between
the torch trigger switch and
connector on PCB at pins CN7/3
or CN7/4.
C Check the continuity from
connector to the torch trigger
switch. Repair the defective
electrical connection.
D MIG Torch has been damaged
internally, trigger wires are making
contact with welding power cable.
D Repair the torch.
2 The contactor operates
when the torch trigger
switch is depressed but
the wirefeed motor does
not rotate.
A The 30VAC for the wire feed motor
is not connected to PCB.
A Check for 30V AC on PCB at
pins CN5/1 & CN5/2. Repair
fault.
B Bad electrical connection between
the wiper arm on the wire speed
potentiometer and connector on
PCB at pin CN8/2 or CN8/3.
B Check the continuity from
connector to the wire
speed potentiometer.
Repair the defective electrical
connection.
C Bad electrical connection between
the wirefeed motor and connector
on PCB at pins CN9/3 or CN9/1.
C Check continuity between the
wirefeed motor and connector.
Repair fault.
D Motor fuse (circuit breaker) FU2
open.
D Check fuse (circuit breaker)
3 The wirefeed motor
operates at maximum
speed and cannot be
adjusted.
Bad electrical connection between
the wire speed potentiometer and
connector on PCB at pin CN8/1.
Check the continuity from
connector to the wire
speed potentiometer.
Repair the defective electrical
connection.
4 Wirefeed motor operates
when the torch trigger
switch is depressed but
the gas valve and the
Power Source contactor
do not operate.
Bad electrical connection(s)
between the connector on PCB at
pin CN1/1 & CN1/3 and the wires
to the contactor coil or gas valve
Repair the broken wire(s) or
termination point(s) after the
fault has been isolated.
Table 6 -16 Power Source or Wirefeeder Faults
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