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TROUBLESHOOTING & REPAIR
F-6
F-6
SQUARE WAVE TIG 275
Observe Safety Guidelines
TROUBLESHOOTING GUIDE
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
OUTPUT PROBLEMS
No output from the machine in
either Stick or TIG modes. The
thermal light is on.
1. The welding application may
have exceeded the recom-
mended duty cycle. Allow the
fan to cool the unit until the ther-
mal light is off.
2. The air louvers may be blocked.
Remove the air obstruction and
allow the unit to cool.
1. One of the thermostats may be
faulty. Check or replace. See
the Wiring Diagram.
2. Check for loose or faulty wires
on the thermostats and associ-
ated circuitry. See the Wiring
Diagram.
3. The fan motor may be faulty or
mechanically obstructed. The
fan should run when welding or
when a thermostat is open.
4. The control board may be faulty.
The machine does not respond (no
gas flow, no high frequency and no
open circuit voltage) when the arc
start switch or Amptrol is activated.
The thermal light is not lit.
1. Make certain the machine is in
the TIG mode.
2. The Amptrol or arc start switch
may be defective. Check for
continuity (zero ohms) between
pins “D” and “E” on the cable
connector when the Amptrol or
arc start switch is pressed.
1. Check the continuity (zero
ohms) of the leads between the
remote receptacle and plug J7
on the control board. See the
Wiring Diagram.
2. Perform the
T1 Transformer
Test.
3. The control board may be faulty.