Lincoln Electric PRECISION TIG 375 Service Manual page 53

F-7
TROUBLESHOOTING GUIDE
PROBLEMS
(SYMPTOMS)
The machine does not have welding
output in the Stick mode.
machine operates correctly in the
TIG mode.
SEE NOTE BELOW
The machine has welding output in
the Stick mode but no output in the
TIG mode. ( no gas flow or high fre-
quency).
SEE NOTE BELOW
The machine welds at a very low
output regardless of the current
control setting.
NOTE: BEFORE REPLACING A
CONTROL BOARD
If an Advanced Control Panel is
installed, remove it and replace
the Jumper in connector J-3. If
the machine functions normally,
the Advanced Process panel or
harness is defective.
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.
TROUBLESHOOTING & REPAIR
POSSIBLE AREAS OF
MISADJUSTMENT(S)
OUTPUT PROBLEMS
1. Check the electrode cable and
The holder for loose or faulty connec-
tions.
2. Make sure the Stick/TIG switch is
in the proper position and operat-
ing correctly.
1. Make sure the Stick/TIG switch is
in the proper position and operat-
ing correctly.
2. The remote control device may
be faulty.
1. If welding in the TIG mode, the
remote control device may be
defective.
2. Make certain the input line volt-
age is correct for the machine's
reconnect configuration.
3. Check the welding cables and/ or
torch for loose or faulty connec-
tions.
CAUTION
PRECISION TIG 375
Observe Safety Guidelines
detailed in the beginning of this manual.
RECOMMENDED
COURSE OF ACTION
1. Check the Stick/TIG switch and
associated leads. See the Wiring
Diagram.
2. The control board may be faulty.
1. Check the remote control recep-
tacle and associated wiring. See
the Wiring Diagram.
2. Perform the Protection Board
Test.
3. Check the J11 plug on the con-
trol board. See the Wiring
Diagram.
4. The control board may be faulty.
1. Check the polarity switch and
associated leads.
2. Check the interior connections of
the heavy current carrying leads.
3. Perform the SCR Bridge Test.
4. Perform the T1 Transformer
Test.
5. Check the output current con-
trols for proper
Normal resistance is 10,000
ohms. See the Wiring Diagram.
6. The control board may be faulty.
F-7
operation.