Lincoln Electric DC-655 service manual Welding Problems

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F-11			F-11
	TROUBLESHOOTING & REPAIR
	Observe Safety Guidelines		TROUBLESHOOTING GUIDE
	detailed in the beginning of this manual.
	PROBLEMS	POSSIBLE AREAS OF	RECOMMENDED
	(SYMPTOMS)	MISADJUSTMENT(S)	COURSE OF ACTION
		WELDING PROBLEMS
	Poor arc characteristics in all	1. Check the three-phase input	1. Check the weld mode switch
	processes.	line voltage at the machine.	(SW2) and associated leads for
		The input voltage must match	proper operation or loose or
		the rating plate and reconnect	faulty connections. See the
		panel.	Wiring Diagram.
		2. Check the welding cables for	2. Perform the Firing Board Test.
		loose or faulty connections.	3. Perform the SCR Bridge Test.
		3. Make sure the proper welding	4. Perform the Main Transformer
		procedures are being used.
			Test.
		(Wire feed speed, arc voltage
		and wire size)	5. The control board may be
		4. Make sure the negative welding	faulty. See the Control Board
			LED Chart.
		cable is connected to the cor-
		rect negative output terminal.
		(Low or High inductance)
	Poor arc striking with semiauto-	1. Make sure the proper welding	1. Perform the Firing Board Test.
	matic or automatic wire feeders.	procedures are being used.	2. Perform the SCR Bridge Test.
		(Wire feed speed, arc voltage
		and wire size)	3. The control board may be
		2. Check the welding cables for	faulty. See the Control Board
			LED Chart.
		loose or faulty connections.

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con- tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-800-833-9353.

IDEALARC DC-655