TW6900 Troubleshooting
Problem
Possible Cause
Fix
Unit will not turn on
No power
1.
Test 3 phase power to control contactor
2.
Check taps (if applicable) on main transformer
3.
Check voltage selection plug near control transformer
4.
Check fuse located on control transformer
5.
Look for power available LED on control transformer
6.
Make these checks before contacting a TWE Rep
Fan does not run when unit is
turned on
This is normal
The fan will cycle on when the main bridge has reached nom-
inal operating temperature. Ambient temperature of the
weld site should also be taken in consideration.
Fan runs continuously (does
not cycle on/off)
Thermostat circuit
A fault in the thermostatic circuit will cause the fan to run
continuously, call a local TRU
-
WELD rep. for repairs
Unit turns on, coil boot test is
good, no trigger from weld
gun
Bad connection or
faulty equipment
1.
Test control cable by plugging weld tool directly into unit
(4 conductor straight through wiring)
2.
Check gun trigger resistance (<100 ohms when closed)
3.
Check to see if trigger LED on control panel responds
4.
Check to see if weld tool is wired accordingly
5.
Locate Touch/Trigger control board #16002, check and
note the operation of the driver LED’s and report the
status
Unit turns on, no coil test, no
lift from gun coil, trigger is
good
Bad connection or
faulty equipment
1.
Test control cable by plugging weld tool directly into unit
(4 conductor straight through wiring)
2.
Check 10 amp fuse on control board box next to breakers
3.
Check hand tool coil resistance (12
-
40 ohms)
4.
Locate Touch/Trigger Control Board TWE16158
-
1, check
and note the operation of the driver LED’s and report the
status
Gun lifts, no weld arc drawn
Bad connection or
faulty equipment
1.
Check connections for ground and weld tool leads
2.
Check if contact LED on control panel lights when stud is
touched to work surface (closing circuit)
3.
Check the two circuit breakers on the control board box
4.
Check to see if you have the sustaining arc (a small blue
arc for the duration of the weld time)
5.
Check to see if the stud sparks at the end of the weld
cycle (hot plunge)
6.
Locate Touch/Trigger Control Board TWE16158
-
1, check
and note the operation of the driver LED’s and report the
status
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