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E-2
TROUBLESHOOTING
E-2
Observe all Safety Guidelines detailed throughout this manual
PROBLEMS
(SYMPTOMS)
POSSIBLE
CAUSE
RECOMMENDED
COURSE OF ACTION
Input contactor (CR1) chatters.
Machine input contactor does not
operate.
Machine input contactor operates,
but no output when trying to weld.
Machine has minimum output and
no control.
1. Faulty input contactor (CR1).
Repair or Replace.
2. Low line voltage.
Check input power.
1. Supply line fuse blown. Replace if
blown - look for reason first.
2. Contactor power circuit dead.
Check control transformer T2 and
associated leads.
3. Broken power lead. Check input
voltage at contactor.
4. Wrong input voltage. Check volt-
age against instructions.
5. Open input contactor coil.
Replace coil.
6. POWER “I/0” switch (S1) not
closing. Replace switch.
1. Trigger circuit between #2 and #4
leads is not being closed. Make
sure trigger circuit is being
closed.
2. Electrode or work lead loose or
broken. Repair Connection.
3. Open main transformer (T1) pri-
mary or secondary circuit. Repair.
4. Defective Control PC Board.
Replace. See Procedure for
Replacing PC Boards.
5. Primary or secondary thermostats
open. Amber thermal protection
light is on: Check for overheat-
ing; make sure fan is operating
and there is no obstruction to free
air flow.
1. Terminals 75, 76 or 77 grounded
to positive
output.
If all recommended possible areas
of misadjustment have been
checked and the problem persists,
Contact your local Authorized
Field Service Facility.
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
DC-400