Troubleshooting - Miller Electric MARK VIII-2 Owner's Manual

6-4. Troubleshooting

Trouble
No weld output from any module; fan
motors off; pilot light off.
No weld output from any module; fan
motors on; pilot light off.
No weld output from any module; fan
motors on; pilot light on.
Limited output and low open circuit volt-
age from All modules.
No weld output from one module only.
Low weld output from one module only.
No amperage control.
Erratic weld output.
No weld output at 115 volts ac duplex
receptacle.
Fan motor(s) does not run when On
push button is pressed.
For GTAW, wandering arc − poor control
of direction of arc.
Tungsten electrode oxidizing and not re-
maining bright after conclusion of weld.
OM-218 Page 24
Y Turn Off polyweld system, and disconnect input power
before inspecting, maintaining, or servicing.
Place line disconnect device in On position (see Section 4-10).
Check line fuse(s), and replace if needed. Reset circuit breakers (see Section 4-10).
Check for proper input connections (see Section 4-10).
Check position of input voltage jumper links (see Section 4-10).
Be sure power switch is On (see Section 5-3).
Check fuse F3 and/or F4, and replace if needed (see Section 6-2).
Have Factory Authorized Service Station/Service Distributor check Start/Stop push buttons PB1/PB2
and replace if necessary.
Thermostat TP1 open (overheating). Allows fans to run; thermostat closes when unit has cooled (see
Section 6-2).
Have Factory Authorized Service Station/Service Distributor check contactor W and replace if needed.
Check incoming power for correct voltage. Replace line fuse if open or reset circuit breaker (see Section
4-10).
Check position of input voltage jumper links (see Section 4-10).
Check fuse links, and replace if needed (see Section 6-2).
Place Remote Amperage control switch in Off position or connect remote amperage control to Remote
Amperage Control receptacle (see Section 5-2).
Check module fuse link, and replace if needed (see Section 6-2).
Reset module supplementary protector (see Section 6-2).
Module thermostat open (overheating). Allow module to cool down; thermostat closes when module has
cooled (see Section 6-2).
Tighten all weld cable connections (see Section 4-6).
Check for proper size and type of cable (see Section 4-10).
Check for proper input and output connections (see Sections 4-10 and 4-6).
Use dry, properly stored electrodes.
Reset overload supplementary protector CB1 (see Section 6-2).
Check fuse F3 and/or F4, and replace if needed (see Section 6-2).
Check fuse F3 and/or F4, and replace if needed (see Section 6-2).
Have Factory Authorized Service Station/Service Distributor check control relay CR1 and fan motor FM1
or FM2.
Select proper size tungsten (see Section 8-1).
Properly prepare tungsten (see Sections 8-2 or 8-3).
Shield weld zone of drafts.
Properly prepare tungsten (see Sections 8-2 or 8-3).
Replace torch parts if water has leaked into torch.
Remedy