Lincoln Electric SVM101-B service manual Figure F.21 Thermal Protection AC Trigger Circuit

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F-45 TROUBLESHOOTING & REPAIR F-45

THERMAL PROTECTION AC TRIGGER CIRCUIT (cont.)

FIGURE F.21 - THERMAL PROTECTION AC TRIGGER CIRCUIT

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T1

EXTERNAL

TRIGGER

#212C #212A

2 C

4 D

#223B

PART OF 14 PIN

AMPHENOL

			CHOKE	FAN
			THERMOSTAT	THERMOSTAT
#503	#503A		#224
24
VOLTS
AC			NORMALLY CLOSED
			NOTE:
10J6			WHEN THERMOSTATS
			TRIP, THE CIRCUIT
#212D	POWER
			WILL BE OPENED
#212B	BOARD
9J6
S4 OUTPUT
TERMINAL
SWITCH
#223A	11J4	CONTROL	4J2	#210
		BOARD

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4.Locate the Auxiliary Transformer T1 and leads used for test. See Figure F.21.

5.Turn main power ON.

6.Test Auxiliary Transformer voltage for 24 VAC between leads 503 and 212D. See Figure F.21.

a.If 24 VAC is present, transformer is OK. Go to step 7.

b.If 0 VAC is present, test input voltage to Auxiliary Transformer.

c.If input voltage to Auxiliary Transfor-mer is cor- rect, replace Auxiliary Transformer.

d.If input voltage to Auxiliary Transfor-mer is not correct, check Line Switch S12 and connecting leads.

7.Check that Output Terminal Switch S4 is in the ON position (closed).

8.Test for 24 VAC between leads 223A and 210.

a.If 24 VAC is present, then AC Trigger Circuit is functioning normally.

b.If 0 VAC is present, check Choke Thermostat and Fan Thermostat.

V300-I