Troubleshooting - Miller Electric S-75D Owner's Manual

7-3. Troubleshooting

Trouble
Wire feeds, shielding gas flows, but
electrode wire is not energized.
Wire feeder is on, display does not light
up, motor does not run, gas valve and
welding power source contactor do not
pull in.
Electrode wire feeding stops or feeds
erratically during welding erratically during welding.
Motor runs slowly.
Wire feeder power is on, displays light
up, feeder jogs, purges, but unit is in-
operative.
When triggered wire feeds but no gas,
no contactor.
Y Disconnect power before troubleshooting
Check cable connections. Check cables for continuity, and repair or replace cables if necessary
(see Section 5-2).
Check and reset circuit breaker at welding power source.
Check gun trigger connection. See gun Owner's Manual.
Check gun trigger. See gun Owner's Manual.
Readjust hub tension and drive roll pressure (see Section 5-10).
Change to correct size drive roll (see Section 5-6 and Table 9-1).
Clean or replace dirty or worn drive roll.
Incorrect size or worn wire guides.
Replace contact tip or liner. See gun Owner's Manual.
Remove weld spatter or foreign matter from around nozzle opening.
Have Factory Authorized Service Agency check drive motor or motor control board PC1.
Check for correct input voltage.
Check welding gun trigger leads for continuity, and repair leads or replace gun.
If the welding arc does not establish in 3 seconds after the gun trigger is activated the unit will feed
wire, but turns off contactor and gas valve. If the gun trigger is still activated after two minutes, the
wire will stop feeding.
Remedy
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