Troubleshooting - Miller Millermatic 250X Owner's Manual

4-9. Troubleshooting

Trouble
No weld output; wire does not feed.
No weld output; wire feeds.
Low weld output.
Fan motor does not run.
Low, high, or erratic wire speed.
No wire feed.
OM-1320 Page 26
Remedy
Be sure line disconnect switch is On (see Section 2-13).
Replace building line fuse or reset circuit breaker if open (see Section 2-13).
Reset circuit breaker CB1 (see Section 4-2).
Secure gun trigger connections (see Section 2-6).
Have Factory Authorized Service Agent check Power switch.
Have Factory Authorized Service Agent check all board connections and main control board.
H – – message appears on voltmeter display to indicate thermostat TP1 is open and unit is in an
overheated condition (see Section 3-2).
Thermostat TP1 open (overheating). Allow fan to run; the thermostat will close when the unit has
cooled (see Section 2-2).
Connect work clamp to get good metal to metal contact.
Replace contact tip (see Section 4-4).
Have Factory Authorized Service Agent check main control board and main rectifier.
Connect unit to proper input voltage or check for low line voltage (see Section 2-13).
Check input voltage jumper links and correct position if necessary (see Section 2-11).
Have Factory Authorized Service Agent check main control board.
Have Factory Authorized Service Agent check fan-on-demand circuit.
Readjust front panel settings (see Section 3-1).
Change to correct size drive rolls (see Section 4-5).
Readjust drive roll pressure (see Section 2-14).
Replace inlet guide, contact tip, and/or liner if necessary (see Sections 4-4, and 4-7).
Check position of input jumper links (see Section 2-11).
Have Factory Authorized Service Agent check main control board.
Reset circuit breaker CB1 (see Section 4-2).
Turn Wire Speed control to higher setting (see Section 3-1).
Clear obstruction in gun contact tip or liner (see Sections 4-4, and 4-7).
Readjust drive roll pressure (see Section 2-14).
Change to correct size drive rolls (see Section 4-5).
Rethread welding wire (see Section 2-14).
Check gun trigger and leads. Repair or replace gun if necessary.
Have Factory Authorized Service Agent check main control board.
H – – message appears on voltmeter display to indicate thermostat TP1 is open and unit is in an
overheated condition (see Section 3-2).