Lincoln Electric IM318-B manual Troubleshooting Guide, Electric Shock can kill

TROUBLESHOOTING GUIDE

WARNING

ELECTRIC SHOCK can kill.

•Have a qualified individual install and service this equipment.

•Turn the input supply power OFF at the disconnect switch or fuse box before working on this equip- ment.

•Do not touch electrically hot parts.

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Note: To locate the “Firing Circuit” and “Control/Fault Protection Circuit” P.C. boards, remove the upper case panel on the left side of the machine. The names are printed on the boards.

Observe all Safety Guidelines detailed throughout this manual

	PROBLEMS	POSSIBLE CAUSE	REMEDY
	(SYMPTOMS)
Input contactor (CR1) chatters.		a. Faulty input contactor (1CR).	a. Repair or replace.
		b. Low line voltage.	b. Check with power company.
		c. Faulty pilot relay (2CR).	c. Replace relay.
Machine input contactor does not operate.		a. Supply line fuse blown.	a. Replace if blown. Look for reason first.
		b. Contactor power circuit dead.	b. Check pilot transformer T1 and associated leads
			and 5 amp fuse.
		c. Broken power lead.	c. Check input voltage at contactor.
		d. Wrong input voltage.	d. Check voltage against nameplate.
		e. Primary or power SCR thermostats open.	e. Check for overheating. Make sure both fans are
			operating and there is no obstruction to free air flow.
			Faulty thermostats — replace.
		f. Open input contactor coil.	f. Replace coil.
		g. Faulty on-off switch.	g. Replace switch.
		h. Faulty pilot relay (2CR).	h. Replace relay.
Machine input contactor operates but no output		a. Electrode or work lead loose or broken.	a. Repair connection.
when trying to weld.		b. Open main transformer (T5) primary or sec-	b. Repair.
		ondary circuit.
		c. “Firing Circuit” P.C. board not connected or is	c. All nine light emitting diodes (L1 thru L9) must be
		faulty.	lit. (See “P.C. Board Troubleshooting Guide”.)
		d. Output pilot relay (6CR) not operating or faulty.	d. Check relay by connecting a jumper across termi-
			nals 2 and 4 on DC-1500 terminal strip. Replace if
			faulty.
Machine has maximum output but no control.		a. “Output Control” switch (SW4) in wrong position.	a. Check position of switch.
		b. “Output Control” switch faulty.	b. Check switch and replace if faulty.
		c. Open in feed back circuitry.	c. Check wiring and control and “Firing Circuit” P.C.
		d. Faulty “Control/Fault Protection” or “Firing Circuit”	board wiring harness plugs.
		P.C. boards.	d. All light emitting diodes must be lit, except L4 on
			“Control/Fault Protection” board. (See “P.C. Board
			Troubleshooting Guide.”)
		e. Output control potentiometer open (lead no. 75).	e. Check and replace if faulty.
	Machine does not have maximum output.	a. One input fuse blown.	a. Check and replace if blown after checking for rea-
			son for blown fuse.
		b. One phase of main transformer open.	b. Check for open and repair.
		c. Faulty “Control/Fault Protection” or “Firing Circuit”	c. All light emitting diodes must be lit on both P.C.
		P.C. boards.	boards, except L4 on “Control/Fault Protection”
			board. (See “P.C. Board Troubleshooting Guide.”)
		d. Output control potentiometer defective.	d. Check and replace if faulty.
		e. Output control potentiometer leads open 226,	e. Check and repair broken leads.
		237, 236, 73, 74, 76, 77.
Machine has output but trips off immediately.		a. Machine has either an internal or external short	a. Check internally and externally for any shorts and
		circuit on the output.	remove or repair.
		b. Faulty “Control/Fault Protection” P.C. board.	b. If no short circuits, LED L4 must be lit (See “P.C.
			Board Troubleshooting Guide”).
		c. Machine output voltage applied to control leads.	c. Check control cable or wire feeder for shorted or
			grounded control leads.

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.

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