Troubleshooting - Miller Electric D-74DX Owner's Manual

9-2. Troubleshooting

Trouble
Wire feeds, shielding gas flows, but elec-
trode wire is not energized.
Wire feeder is on, meter(s) do not light
up, motor does not run, gas valve and
welding power source contactor do not
pull in.
Electrode wire feeding stops or feeds er-
ratically during welding.
Motor runs slowly.
Wire does not feed until trigger is pulled,
but continues to feed after trigger is re-
leased, and trigger hold is not on.
Gas valve in feeder is rattling loudly
along with possible erratic or slow wire
feed speed.
Wire feeder power is on, displays light
up, but unit is inoperative.
OM-1500-7 Page 32
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Disconnect power before troubleshooting.
Check interconnecting cord connections. If secure, check cord for continuity and repair or replace (see
Sections 5-2 and 5-3).
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 5-7).
Change to correct size drive roll (see Table 11-1).
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 for a short between welding gun trigger leads and weld cable. Repair short or replace welding gun.
Check for a short between welding gun trigger leads and weld cable. Repair short or replace welding gun.
Check welding gun trigger leads for continuity, and repair leads or replace gun.
Remedy