Troubleshooting - Miller Axcess 450 Owner's Manual

8-5. Troubleshooting

Trouble
No weld output; completely inoperative
No weld output; meter display on with no
error displayed.
Erratic or improper weld output with no
errors displayed.
No 115 volts AC at the duplex
receptacle.
Wire does not feed.
Wire feeds erratically.
Wire feeds as soon as power is supplied. Check gun trigger. See gun Owner's Manual.
Wire stubbing on low end using a
constant current power source. constant current power source
Gas does not flow or does not stop flow-
ing; wire feeds.
Wire burns back to gun contact tip when
using electrode negative
polarity) process.
Place line disconnect in On position (see Section 3-12).
Check and replace line fuse(s), if necessary, or reset circuit breaker
(see Section 3-12).
Check for proper input power connections (see Section 3-12).
Check to see if the contactor indicator light is lit when contactor line is asserted on.
Use proper size and type of weld cable (see Section 4-1).
Clean and tighten all weld connections.
Reset supplementary protector CB1 (see Section 3-7).
Check supplementary protector CB2 and reset if necessary (see Section 3-7).
Check motor control cable connections.
Readjust hub tension.
Readjust drive roll pressure.
Clean or replace dirty or worn drive rolls.
Remove weld spatter around the nozzle opening.
Replace contact tip or liner. See gun Owner's Manual.
Check motor control cable connections.
Increase output setting of the power source.
Check voltage sense lead connection, clean and tighten if necessary.
Check gas valve and flow meter.
Check to be sure that volt sense lead is connected to the work.
(straight
Remedy
OM-211 434 Page 31