Miller Electric Troubleshooting Common Welding Problems with the Miller Big Blue 300 and Pro 300

8-12. Troubleshooting

. Also see Voltmeter/Ammeter help displays to assist in troubleshooting weld problems (see Section 8-11).

A. Welding

Trouble	Remedy
No weld output; generator power output	Place Process/Contactor switch in a Weld Terminals Always On position, or place switch in a Remote
okay at ac receptacles.	On/Off Switch Required position and turn remote contactor on (see Section 5-9).
	Reset supplementary protector CB7 or CB8 (see Section 8-9). 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).
No weld output, or generator power out-	Disconnect equipment from generator power receptacles during start-up.
put at ac receptacles.
	Reset supplementary protector CB3. (see Section 8-9).
	Check fuse F1, and replace if open (see Section 8-9). 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.
Erratic weld output.	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.
High weld output.	Have Factory Authorized Service Agent check main control module PC1 and hall device HD1.
Low weld output.	Check engine speed, and adjust if necessary.
	Check fuse F1, and replace if open (see Section 8-9). If F1 is open, have Factory Authorized Service
	Agent check the rotor.
Low open-circuit voltage.	Check engine speed, and adjust if necessary.
	Have Factory Authorized Service Agent check main control module PC1, voltage regulator module PC3,
	and main rectifier.
No remote fine amperage control.	Repair or replace remote control device.
	Check and secure connections to Remote Amperage Adjust receptacle RC14 (see Section 5-9).
No 24 volt or 115 volt ac output at Re-	Reset supplementary protector CB7 (24 volt) or CB8 (115 volt) (see Section 8-9).
mote receptacle RC14.

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