Troubleshooting - Miller Electric MPi 220P Owner's Manual

6-4. Troubleshooting

A. MIG (GMAW) Welding
Trouble
No weld output; wire does not feed.
No weld output; wire feeds.
Low weld output.
Low, high, or erratic wire speed.
No wire feed.
Remedy
Be sure line disconnect switch is On (see Section 4-11).
Replace building line fuse or reset circuit breaker if open (see Section 4-11).
Secure gun trigger connections (see welding gun Owner's Manual).
Check continuity of power switch S1 and replace if necessary.
Have Factory Authorized Service Agent check main transformer T1 for signs of winding failure. Check
continuity across windings and check for proper connections. Check secondary voltages. Replace T1
if necessary.
Have Factory Authorized Service Agent check continuity of thermostats TP1 and TP2. Replace TP1
and/or TP2 if necessary.
Have Factory Authorized Service Agent check main control board PC2 and connections, and replace if
necessary.
Have Factory Authorized Service Agent check all board connections and main control board.
Connect work clamp to get good metal to metal contact.
Replace contact tip (see welding gun Owner's Manual).
An overload condition occurred (see Section 6-3).
Have Factory Authorized Service Agent check primary and secondary power circuit of the unit.
Have Factory Authorized Service Agent check main transformer T1 for signs of winding failure. Check
continuity across windings and check for proper connections. Check secondary voltages. Replace T1
if necessary.
Have Factory Authorized Service Agent check voltage switch(es), and replace if necessary.
Connect unit to proper input voltage or check for low line voltage (see Section 4-11).
Readjust front panel settings (see Section 5).
Change to correct size drive rolls (see Section 4-8).
Readjust drive roll pressure (see Section 4-12).
Replace inlet guide, contact tip, and/or liner if necessary (see welding gun Owner's Manual).
Have Factory Authorized Service Agent check Wire Speed control, and replace if necessary.
Have Factory Authorized Service Agent check motor control board PC4 and connections, and replace
if necessary.
Rotate Wire Speed control to higher setting (see Section 5).
Clear obstruction in gun contact tip or liner (see welding gun Owner's Manual).
Readjust drive roll pressure (see Section 4-12).
Change to correct size drive rolls (see Section 4-8).
Rethread welding wire (see Section 4-12).
Check gun trigger and leads. Repair or replace gun if necessary.
Have Factory Authorized Service Agent check main control board.
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