ESAB ESP-150 - Troubleshooting

49
5.1 Troubleshooting
Check the problem against the symptoms in the following troubleshooting guide. If the cause cannot be
quickly located, shut o the input power, open up the unit, and perform a simple visual inspection of all the
components and wiring. Check for components, bulged or leaking capacitors, or any other sign of damage or
discoloration.
The cause of control malfunctions can also be found by referring to the sequence of operations and electrical
schematic diagram and check out the various components. A volt-ohmmeter will be necessary for some of
these checks.
NOTE: Beforecheckingvoltagesinthecircuit,disconnectthepowerfromthehighfrequencygeneratortoavoiddam-
agingyourvoltmeter.
Be sure unit is set up properly for voltage being used and that the gas supplies are adequate.
A. TROUBLESHOOTING GUIDE
1. Unit Inoperative; fan does not run.
a. Check primary disconnect switch to make sure input power is being supplied.
b. Check links on the input terminal board TB to make sure all are connected to the proper input voltage
being used. (See Form 14-376.)
c. Check for defective power switch (ROS).
2. No gas ow when torch switch is closed.
a. Unplug torch switch plug and check for proper operation with an ohmmeter connected to pins 1 and 2 of
torch switch plug.
b. Defective interlock switch (ISW).
c. Check for defective solenoid valves.
d. Plug (P1) may be loose at control board.
e. Defective logic board.
3. Pilot arc-high frequency sparks noted at spark gap but not at the torch.
a. Check spark gap and readjust electrodes if necessary. Replace spark gap electrodes if worn beyond service-
ability.
b. Check with an ohmmeter for continuity between torch nozzle and POS output where torch attaches to
console.
4. No pilot arc-high frequency sparks noted at spark gap and at torch during preow, but main contactor
does not activate or chatters at end of 2 second preow time.
a. Check start gas pressure. It must be at least 30 psig.
b. Check cooling gas pressure (PT-26). It must be at least 50 psig.
c. If using PT-26 torch, check jumper plug between J1-5 and J1-4 on the torch switchplug.
d. Thermal switch in bridge, inductor, or main transformer may be open. Allow unit to cool down.
e. Defective logic board (675369).
5. No pilot arc - No spark noted in the spark gap.
a. Check to see that pilot arc contactor (PAC) closes. If it does not, and gas ows when torch switch is closed,
replace logic board.
b. If PAC closes, check for proper spark gap setting (0.040-in.).
c. Check the 120V input to the high voltage transformer (HFTR).
d. Check for arcing or carbon tracking around the spark gap.
e. If all of the above check good, HFTR is most likely defective.
6. Erratic pilot arc - pilot arc contactor (PAC) chatters.
a. Defective logic board.
b. Power supply may be single phasing. Check main disconnect switch and fuses.
SECTION 5 MAINTENANCE