Miller Electric Big Blue 502P, Big Blue 402P manual Troubleshooting, A. Welding − CC Models

9-9. Troubleshooting

A. Welding − CC Models

Trouble	Remedy
No weld output; generator power output	Check position of Ampere Range switch.
okay at ac receptacles.
	Check position of optional polarity switch.
	Place Amperage Adjust switch in Panel position, or place switch in Remote position and connect remote
	control to Remote Amperage Adjust receptacle RC13 (see Sections 5-10and 6-1).
	Check and secure connections to Remote Amperage Adjust receptacle RC13 (see Section 5-10).
	Check fuse F2, and replace if open (see Section 9-7). Have Factory Authorized Service Agent check inte-
	grated rectifier SR2 and the rotor.
	Have Factory Authorized Service Agent check brushes and slip rings, and field excitation circuit.
No weld output or generator power out-	Disconnect equipment from generator power receptacles during start-up.
put at ac receptacles.
	Check fuses F1 and F2, and replace if open (see Section 9-7). Have Factory Authorized Service Agent
	check integrated rectifier SR1, capacitor C9, integrated rectifier SR2, and the rotor.
	Reset circuit breaker CB12. Have Factory Authorized Service Agent check diode D1 (see Section 9-7).
	Have Factory Authorized Service Agent check brushes and slip rings, 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.	Check engine speed, and adjust if necessary.
	Have Factory Authorized Service Agent check OCV control circuit.
Low weld output.	Check engine speed, and adjust if necessary.
	Check fuses F1 and F2, and replace if open (see Section 9-7). Have Factory Authorized Service Agent
	check integrated rectifier SR1, capacitor C9, integrated rectifier SR2, and the rotor.
Electrode sticks to the workpiece more	Circuit breaker CB4 may be open. CB4 automatically resets when the fault is corrected (see Section 9-7).
frequently during low voltage (short arc	Have Factory Authorized Service Agent check transformer T1 and integrated rectifiers SR4 and SR5.
length) conditions.
Low open-circuit voltage.	Check engine speed, and adjust if necessary.
Maximum weld output only in each	Have Factory Authorized Service Agent check control relay CR7.
ampere range (with Stick/TIG Selection
switch in Stick position).
No remote fine amperage control.	Place Amperage Adjust switch in correct position.
	Check and secure connections to Remote Amperage Adjust receptacle RC13 (see Section 5-10).
	Reset circuit breaker CB11 (see Section 9-7). Have Factory Authorized Service Agent check control relay
	CR7.
	Repair or replace remote control device.
	Have Factory Authorized Service Agent check OCV control circuit.

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