Lincoln Electric IM318-B manual Board Troubleshooting Guide, Electric

TROUBLESHOOTING GUIDE

PROBLEMS		POSSIBLE CAUSE		REMEDY
(SYMPTOMS)
Variable or sluggish welding arc.	a.	Poor work or electrode connection.	a.	Check and clean all connections.
	b.	Welding leads too small.	b.	Check table on page 4.
	c.	Welding current or voltage too low.	c.	Check procedures for recommended settings.
Machine will not shut off.	a.	Input contacts frozen.	a.	Check for approximately .13 inch over travel
				of contacts.
	b.	Pilot relay contacts stuck closed.	b.	Check and replace if necessary.
Output control not functioning on	a.	“Output Control” switch in the wrong	a.	Place switch in “Output Control at
the machine.		position.		DC-1500”.
	b.	Faulty output control switch.	b.	Check and replace if found faulty.
	c.	Faulty “Output Control” rheostat.	c.	Check and replace if found faulty.
	d.	Leads or connections open in “Control	d.	Check lead continuity and connections for an
		Circuit”.		open and repair if necessary.
	e.	Faulty “Firing Circuit” or “Control/Fault	e.	All light emitting diodes must be lit on both
		Protection” P.C. board.		P.C. boards, except L4 on “Control/Fault
				Protection” board. (See “P.C. Board
				Troubleshooting Guide.”)
Output control not functioning on	a.	“Output Control” switch in the wrong	a.	Place switch in “Output Control Remote”.
remote control.		position.
	b.	Faulty output control switch.	b.	Check and replace if found faulty.
	c.	Faulty remote control rheostat.	c.	Check and replace if found faulty.
	d.	Leads or connections open in “Control	d.	Check all leads and connections, internal and
		Circuit”.		remote, for continuity and repair if
				necessary.
	e.	Faulty “Firing” or “Control/Fault	e.	All light emitting diodes must be lit on both
		Protection” P.C. board.		P.C. boards, except L4 on “Control/Fault
				Protection” board. (See “P.C. Board
				Troubleshooting Guide.”)
Machine trips off with High	a.	OCV setting too high.	a.	Reduce OCV setting.
Current Procedures on starting.	b.	Defective control board.	b.	Replace control board.

P.C. BOARD TROUBLESHOOTING GUIDE

WARNING

CONTROL/FAULT PROTECTION P.C. BOARD

1. LED L1 indicates AC input voltage is present at pins

ELECTRIC

SHOCK Can kill.

•Have an electrician install and service this equipment.

•Turn the input power off at the fuse box before working on equipment.

•Do not touch electrically hot parts.

255-256. If not lit, check the voltage across the sec-

ondary winding of the control transformer T7. The volt-

age should be approximately 115 volts. If not, the

problem is in the power supply and not the P.C. board.

2. LED L2 indicates welder output voltage is being sup-

plied to the control circuit. If not lit, check to make

certain 222 from pin 2 of the 12-pin control circuit P.C.

board connector is connected to the power source neg-

ative output stud, and is not broken.

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