Lincoln Electric IM10018-A manual BOARD TROUbLESHOOTING Guide, Control P.C. bOARD

P.C. bOARD TROUbLESHOOTING GUIDE FIRING P.C. bOARD

1. All 10 LED’s must be ON when the POWER SOURCE is turned “ON” and the trigger circuit* is closed.

E-12 TROUbLESHOOTING E-12

Observe all Safety Guidelines detailed throughout this manual

Voltage across leads 255 and 256 should be approximately 115VAC. Check voltage across sec- ondary winding of the control transformer (T2) which supplies leads 255 and 256. Measure +16VDC from TEST POINTS “A” to “C” and -10VDC from TEST POINTS “A” to “J” on Control board.

2. LED’s 7, 8, and 9 indicate AC power being supplied		2. LED 2 indicates welder output voltage is being sup-
		plied to the control circuit. LED 2 will be “ON”
to the P.C. board from auxiliary windings on the
		brightly in CC STICK mode with trigger circuit*
main transformer (T1). If a LED is not “ON”, turn the
		closed and no load. (LED 2 diminishes in bright-
machine off and unplug P5 from the firing board.
		ness as output voltage is reduced). If LED 2 is not
Turn the machine back on and check the following
		“ON”, look for open connection in lead 222 circuit.
voltages:
LED that	Check AC voltage between pins specified,	3. LED 3 indicates power is being applied to FAULT
was off	it should be approximately 32VAC .	PROTECTION RELAY (CR2). LED 3 will be “ON”
7	P5 pins 15 & 16 (wires 203,204)	when machine POWER is “ON”. LED 3 goes “OUT”
8	P5 pins 7 & 8 (wires 205,206)	when CR2 drops out which turns off the INPUT
9	P5 pins 5 & 6 (wires 207,208)	CONTACTOR (CR1). When LED 3 goes out, LED 4
		comes “ON”. See step 3.
3. If all voltages are present, turn power off, and plug
P5 back into J5. Turn power back on. If LED’s are		4. LED 4 indicates an overload or fault condition; LED
still “OUT”, replace Firing P.C.B.
		should not be on. If this LED comes “ON”, the
4. If voltages were not present then check the wiring		INPUT CONTACTOR (CR1) will turn off and the red
		POWER light stays illuminated. This was do to
back to the auxiliary windings for a possible open.
		either a short across output, or a current draw in
5. LED 10 senses when trigger circuit* is closed.		excess of 780A, or leads 75, 76, or 77 grounded to
		negative output lead. Remove short or reduce out-
Close trigger circuit, LED10 should be on be “ON”.
		put current or eliminate ground. Welder must be
Open trigger circuit, LED 10 should be “OFF”. If
		reset by turning POWER ON/OFF switch to “OFF”
LED does not come “ON”, check to make sure
		and then back to “ON”. If no short or loads above
leads 2,4, or 41 are not broken.
		780A exists or no ground, replace Control P.C.B.
6. LED’s 1 through 6 indicate gate signals are being		5. LED 5 indicates DC control voltage (which supplies
sent to the main SCR’s 1 through 6 respectively. If
		Firing board) is present. LED 5 will be “ON” in CV
LED 5 (located on Control Board) is “ON”, along
		INNERSHIELD mode with trigger circuit* closed,
with LED’s 7, 8, and 9 (on Firing P.C.B), and LED’s
		CONTROL POT at minimum, and no load. (LED 5
1 through 6 are “OFF”, check to make sure lead
		diminishes in brightness as output voltage is
231 between Control board and Firing board is
		increased). Replace P.C. board if LED 5 did not go
not broken
		“ON”.
7. If any one of LED’s 1 through 6 are “OFF” and		6. LED 6 indicates trigger circuit* condition. LED 6
LED’s 7, 8, and 9 are “ON”, replace the Firing
		“ON” indicates trigger circuit is closed. LED 6 “OFF”
P.C.B.
		indicates trigger circuit is open. If LED 6 does not
P.C. bOARD TROUbLESHOOTING GUIDE		come “ON”, when trigger circuit closed, look for
		open connections in the 2 & 4 circuit and in leads
CONTROL P.C. bOARD
		290 and 291.
1. LED 1 indicates AC input voltage necessary to gen-		TRIGGER CIRCUIT is closed by any of the following:
erate the DC supply voltages is present. These volt-		• Wire feeder’s trigger is closed.
ages power the Control board circuitry. If LED 1 is		• A jumper is placed across 2 & 4 on terminal strip
not “ON” when machine POWER is “ON”, check		T.S.2. or across pins C & D in 14 pin connector.
leads 255, 256, X1, and X2 for broken connection.		• OUTPUT TERMINAL switch is in the “ON” position.

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.

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