Lincoln Electric SQUARE WAVE TIG 275 IM609-B Operator's Manual page 33

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Observe all Safety Guidelines detailed throughout this manual
PROBLEMS
(SYMPTOMS)
Machine will not turn on.
No machine output.
Control panel display does not func-
tion, but the output is normal.
The Voltmeter always reads "000",
but the output is normal.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your Local
Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.
TROUBLESHOOTING
POSSIBLE AREAS OF
MISADJUSTMENTS(S)
GENERAL MACHINE TROUBLE
1. Input supply not "hot". Check input sup-
ply line voltage and fuses.
2. Input power switch (S1) faulty. Check
and replace.
1. Make sure the input Power Switch (S1) is
in the "ON" position.
2. A protective thermostat may be open.
An open thermostat disables machine
output. Allow machine to cool and ther-
mostat will close. The yellow thermal
light (TL1) should be lit in this condition.
3. If the machine is not "hot" (i.e. you have
not been welding) and the thermostat
light is lit, the thermostat wiring or a ther-
mostat may be faulty. Check for continu-
ity between leads 313 and 314 at P3 on
the Control PC Board. If not present,
test each wire and thermostat individual-
ly.
4. The Control PC Board may be faulty.
See PC Board Troubleshooting
Procedures
5. Main Transformer (T1) may be faulty.
1. Check for loose connections at the
Control PC Board (P4) or at the Display
Board (P20 & P21)..
2. The Display PC Board may be faulty.
See PC Board Troubleshooting
Procedures.
3. The Control PC Board may be faulty.
See PC Board Troubleshooting
Procedures.
1. Check leads 252 and 253 and their con-
nections to the Polarity Switch (S2) and
to the Control PC Board connection (J6).
2. The Display PC Board may be faulty.
See PC Board Troubleshooting
Procedures.
CAUTION
SQUARE WAVE TIG 275
RECOMMENDED
COURSE OF ACTION
Contact your Local Lincoln Authorized
Field Service Facility for technical
troubleshooting assistance.
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