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TROUBLESHOOTING & REPAIR
F-8
F-8
SQUARE WAVE TIG 355
TROUBLESHOOTING GUIDE
Observe Safety Guidelines
detailed in the beginning of this manual.
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
216-383-2531 or 1-800-833-9353.
PROBLEMS
(SYMPTOMS)
POSSIBLE AREAS OF
MISADJUSTMENT(S)
RECOMMENDED
COURSE OF ACTION
FUNCTION PROBLEMS
Digital display does not light.
Machine turns on and operates
normally.
1. Contact your local authorized
Lincoln Electric Field Service
Facility.
1. Check for 5VDC from 2J7+ to
4J7- on the display board. If
the voltage is present and the
display does NOT light, the
display board may be faulty.
Replace.
2. The control board may be
faulty. Replace.
The display lights but a current
cannot be preset.
1. Contact your local authorized
Lincoln Electric Field Service
Facilty.
1. Set the Peak Current control
(R10) to the 12 o’clock posi-
tion. Position the Start Current
switch (S13) to the off position.
The machine should weld at
approximately 80 amps. If the
machine welds properly but
does NOT display the actual
welding current, the meter
board may be defective.
Replace.
1a. The control board may be
defective. Replace.
2. If the machine does NOT weld
properly, check or replace the
Peak Current control poten-
tiometer (R10).
2a. The control board may be
faulty. Replace.