Section 9 − Troubleshooting; Troubleshooting Table - Miller Millermatic 350P Technical Manual

Always perform pre-power troubleshooting before applying power to unit (see Section 8).
SECTION 9 − TROUBLESHOOTING

9-1. Troubleshooting Table

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.
Improper or no gas flow.
TM-1327 Page 48
Be sure line disconnect switch is On (see Section 4-11 or 4-12).
Replace building line fuse or reset circuit breaker if open (see Section 4-11 or 4-12).
Secure gun trigger connections (see Section 4-3).
Check continuity of Power switch S1, and replace if necessary.
If using a plug, check and secure plug to leads at end of power cord.
Check main control board PC1 and connections, and replace if necessary (see Section 9-5).
Thermistor RT1 or RT2 open (overheating). Allow fan to run; the unit will be enabled when it has cooled
and temperatures are within acceptable limits (see Section 3-2 and 10-3).
Connect work clamp to get good metal-to-metal contact.
Replace contact tip (see gun Owner's Manual).
An overload condition occurred. Release gun trigger (see gun Owner's Manual).
Check main control board PC1 and connections, and replace if necessary (see Section 9-5).
Check work cable and clamp (see Section 4-1).
Connect unit to proper input voltage or check for low line voltage (see Section 4-11 or 4-12).
Check main control board PC1 and connections, and replace if necessary (see Section 9-5).
Readjust front panel settings (see Section 5-1).
Change to correct size drive rolls (see Section 10-5).
Readjust drive roll pressure (see Section 4-13, 4-14, or 4-15).
Replace inlet guide, contact tip, and/or liner if necessary (see Sections and gun Owner's Manual).
Check main control board PC1 and connections, and replace if necessary (see Section 9-5).
Clear obstruction in gun contact tip or liner (see gun Owner's Manual).
Readjust drive roll pressure (see Section 4-13, 4-14, or 4-15).
Change to correct size drive rolls (see Section 10-5).
Rethread welding wire (see Section 4-13, 4-14, or 4-15).
Check gun trigger and leads. Repair or replace gun if necessary (see gun Owner's Manual).
Check main control board PC1 and connections, and replace if necessary (see Section 9-5).
H — — message appears on voltmeter and ammeter displays to indicate thermistor RT1 or RT2 is open
and unit is in an overheated condition (see Section 9-2).
Clean or replace gas hose.
Clear blockage in gun (see gun Owner's Manual).
.
See Section 9-3 for test points and values and
Section 8 for parts location.
.
Use MILLER Testing Booklet (Part No. 150 853)
when servicing this unit.
.
See the Miller Extranet for service memos that
may aid in the repair of this product.
Remedy
Millermatic 350