Troubleshooting - Miller PRO 300 Owner's Manual

8-12. Troubleshooting

Note
Also see Voltmeter/Ammeter help displays to assist in troubleshooting weld problems (see
Section 8-11).
A. Welding
Trouble
No weld output; generator power output
okay at ac receptacles.
No weld output, or generator power out-
put at ac receptacles.
Erratic weld output.
High weld output.
Low weld output.
Low open-circuit voltage.
No remote fine amperage control.
No 24 volt or 115 volt ac output at Re-
mote receptacle RC14.
B. Standard Generator Power
Trouble
No generator power output at ac recep-
tacles; weld output okay.
OM-4422 Page 44
Place Process/Contactor switch in a Weld Terminals Always On position, or place switch in a Remote
On/Off Switch Required position and turn remote contactor on (see Section 5-9).
Reset circuit breaker CB7 or CB8 (see Section 8-10). Check for faulty remote device connected to RC14.
Check and secure connections to Remote Control receptacle RC14 (see Section 5-9).
Check Voltmeter/Ammeter help displays (see Section 8-11).
Disconnect equipment from generator power receptacles during start-up.
Reset circuit breaker CB3. (see Section 8-10).
Check fuse F1, and replace if open (see Section 8-10). If F1 is open, have Factory Authorized Service
Agent check the voltage regulator module PC3.
Check Voltmeter/Ammeter help displays (see Section 8-11).
Have Factory Authorized Service Agent check brushes and slip rings, voltage regulator module PC3, and
field excitation circuit.
Check and tighten connections inside and outside unit.
Be sure connection to work piece is clean and tight.
Use dry, properly stored electrodes.
Remove excessive coils from weld cables.
Have Factory Authorized Service Agent check brushes and slip rings.
Have Factory Authorized Service Agent check main control module PC1 and hall device HD1.
Check engine speed, and adjust if necessary.
Check fuse F1, and replace if open (see Section 8-10). If F1 is open, have Factory Authorized Service
Agent check the rotor.
Check engine speed, and adjust if necessary.
Have Factory Authorized Service Agent check main control module PC1, voltage regulator module PC3,
and main rectifier.
Repair or replace remote control device.
Check and secure connections to Remote Amperage Adjust receptacle RC14 (see Section 5-9).
Reset circuit breaker CB7 (24 volt) or CB8 (115 volt) (see Section 8-10).
Reset receptacle circuit breakers (see Section 7-1).
Remedy
Remedy