
F-8
F-8
PRECISION TIG 375
TROUBLESHOOTING & REPAIR
Observe Safety Guidelines
TROUBLESHOOTING GUIDE
detailed in the beginning of this manual.
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.
PROBLEMS
(SYMPTOMS)
POSSIBLE AREAS OF
MISADJUSTMENT(S)
RECOMMENDED
COURSE OF ACTION
OUTPUT PROBLEMS
The machine welds at a very high
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.
1. If welding in the TIG mode, the
remote control device may be
defective.
1. Perform the
2. Perform the
3. Check the output current con-
trols for proper operation. Normal
resistance is 10,000 ohms. See
the Wiring Diagram.
4. Check leads #221 and #222
between the output shunt and
the control board. See the
Wiring Diagram.
5. The control may be faulty.
Accessories plugged into the 120
volt receptacle do not work.
1. Make sure the accessory, plug
and associated leads are in good
working condition.
2. Make certain the correct input
voltage is being applied to the
machine. ( The reconnect lead
must be in the correct position.)
3. The circuit breaker CB1 may be
tripped. Reset if necessary.
4. Only the top part of the recepta-
cle is electronically “Hot” all of the
time.
1. The circuit breaker (CB1) may be
faulty.
2. Check the receptacle and asso-
ciated leads for loose or faulty
connections.
3. Perform the
Output stays on after releasing
hand/foot Amptrol
(machine with
Advanced Control panel only)
1. Downslope is not set at min.
2. Bad Downslope potentiometer
R12 or its connection.
1. Check Downslope setting.
2. Check R12 & its connection.
CAUTION