Lincoln Electric SVM123-A service manual SCR Output

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F-11	TROUBLESHOOTING & REPAIR					F-11
	Observe all Safety Guidelines detailed throughout this manual
PROBLEMS			POSSIBLE AREAS OF		RECOMMENDED
(SYMPTOMS)			MISADJUSTMENT(S)		COURSE OF ACTION
			WELDING PROBLEMS
Poor arc starting when the DC-		1.	Make sure the proper welding	1.	Check the 3CR reed switch.
1000 is in the CV Sub-Arc or CV			procedures are being used		The voltage from lead #215 to
Innershield Modes.			(wire feed speed, arc voltage		lead #220 should be 8 VDC
			and wire size).		when the DC-1000 is in an
					idle condition (on but not
		2.	Check weld cables for loose		welding). When the machine
			or faulty connections.		is producing welding current,
					the reed switch (3CR) should
					close and the voltage from
					#215 to #220 should drop to
					zero.
				2.	Perform the Firing Board
					Test.
				3	Perform the	SCR Output
					Bridge Test.
				4.	The control board may be
					faulty - Replace.
Poor arc characteristics in all		1.	Check for the correct input	1.	Check the	Mode Switch
processes.			voltages on the three phase		(SW4) and the associated
			input lines at the DC-1000.		wiring for loose or faulty con-
					nections. See wiring diagram.
		2. Make sure the proper welding
			procedures are being used	2.	Check the 3CR reed switch.
			(wire feed speed, arc voltage		The voltage from lead #215 to
			and wire size).		lead #220 should be 8 VDC
					when the DC-1000 is in an
		3.	Check the welding cables for		idle condition. When the
			loose or faulty connections.		machine is producing welding
					current, the reed switch (3CR)
					should close and the voltage
					from #215 to #220 should
					drop to zero.
				3.	Perform the Firing Board
					Test.
				4.	Perform the	SCR Output
					Bridge Test.
				5.	The control board may be
					faulty - Replace.

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed. Call 216-383-2531 or 1-800-833-9353.

IDEALARC DC-1000