Troubleshooting; Section 6 − Electrical Diagram - MAC TOOLS MW250 Owner's Manual

5-6. Troubleshooting

WARNING
Welding Trouble
No weld output; wire does not feed.
No weld output; wire does not feed; fan
motor continues to run and pilot light is
off.
No weld output; wire feeds.
Low weld output.
Wire Drive/Gun Trouble
Electrode wire feeding stops during
welding.
SECTION 6 − ELECTRICAL DIAGRAM
Secure power cord plug in receptacle.
Reset circuit breaker CB1. Replace fuse F1 and/or F2.
Replace building line fuse or reset circuit breaker if open.
Secure gun trigger plug in receptacle or repair leads, or replace trig-
ger switch.
Thermostat open (overheating). Allow fan to run; the thermostat will
close when the unit has cooled.
Connect work clamp to get good metal to metal contact.
Replace contact tip.
Connect unit to proper input voltage or check for low line voltage.
Straighten gun cable and/or replace damaged parts.
Adjust hub tension.
Adjust drive roll pressure.
Replace contact tip if blocked.
Clean or replace wire inlet guide or liner if dirty or plugged.
Replace drive roll or pressure bearing if worn or slipping.
Secure gun trigger plug in receptacle or repair leads, or replace trig-
ger switch.
Check and replace F1 and/or F2.
Check and clear any restrictions at drive assembly and liner.
Have nearest Factory Authorized Service Station check drive
motor.
Figure 6-1. Circuit Diagram For Welding Power Source
READ SAFETY BLOCKS at start of
Section 5 before proceeding.
Remedy Section
3-5
5-2
3-5
3-4
5-2
Figure 4-3
5-5
3-5
5-5
3-6
3-7
5-5
5-4, 5-5
5-4
3-4
5-2
5-4, 5-5
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SB-174 099-B
OM-154 501 Page 16