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D-5
TROUBLESHOOTING
D-5
Observe all Safety Guidelines detailed througout this manual
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your Local
Authorized Field Service Facility for technical troubleshooting assistance before you proceed.
CAUTION
FUNCTION PROBLEMS
PROBLEMS
(SYMPTOMS)
POSSIBLE CAUSE
RECOMMENDED
COURSE OF ACTION
H.Machine trips off when under no
load or makes excessive noise
like it is loaded.
I. Variable or sluggish welding arc.
J. Welder will not shut off.
K. Current control on machine not
functioning.
1. Power bridge rectifier may have
a shorted diode or SCR.
2. Short in the transformer.
3. Fan hitting vertical baffle.
1. Poor work or electrode cable
connection.
2. Current too low.
3. Welding leads too small.
4. Open SCR or diode in power
rectifier bridge.
5. Control circuit problems.
1. Input contactor contacts frozen.
1. Current control switch in wrong
position.
2. Current control switch defective.
3. Current control potentiometer
defective.
4. Lead or connection in control
circuit open.
5. Defective control or circuit
boards.
1. Refer to Power Hybrid Bridge
Checking Procedure. See
Troubleshooting Procedures –
Checking Snubber Circuit and
Power Rectifier Bridge Assembly.
2. Repair.
3. Clear the fan.
1. Check and clean cable connec-
tions.
2. Check recommended currents
for rod type and size.
3. See Troubleshooting Procedures
– Fault Protection Operation.
4. Check per Power Hybrid Bridge
Procedures. See
Troubleshooting Procedures –
Checking Snubber Circuit.
5. See Troubleshooting
Procedures.
1. Replace input contactor.
1. Place switch in “machine” posi-
tion.
2. See Troubleshooting Procedures
– Toggle Switch Check.
3. See Troubleshooting Procedures
– Checking Current Control
Rheostat.
4. Repair or connect.
5. See Troubleshooting Procedure
– Power Silicon Controlled
Rectifier.
E500