Lincoln Electric SVM170-A service manual Figure F.7 Location Leads X2

TOC

TOC

F-25	TROUBLESHOOTING AND REPAIR	F-25
	ACTIVE SCR RECTIFIER ASSEMBLY TEST (continued)

Return to Section

to Section TOC

Return to Master

to Master TOC

6.Disconnect leads X2 and X3 (braided copper strap) from the negative capaci- tor bank buss bar using a 1/2 in. open end wrench. See Figure F.7.

FIGURE F.7 — LOCATION OF

LEADS X2 AND X3.

NEGATIVE

CAPACITOR

BANK BUSS

BAR

8.Use a commercial SCR tester or con- struct the tester circuit shown in Figure F.8. One 6-volt lantern battery can be used. R1 and R2 resistor values are ±10%. Set voltmeter scale low, at approximately 0-5 volts or 5-10 volts.

a.Test the voltage level of the battery. Short leads (A) and (C). Close switch SW-1. Battery voltage should be 4.5 volts or higher. If lower, replace the battery.

FIGURE F.8 — SCR TESTER CIRCUIT

AND SCR CONNECTIONS.

Return

Return to Section TOC

Return to Section TOC

Return

Return to Master TOC

Return to Master TOC

LEADS X2 AND X3

CONNECTION

7.Separate leads X2 and X3 from the negative capacitor bank buss bar. Be sure there is no electrical contact.

NOTE: DO NOT DISASSEMBLE THE SCR RECTIFIER HEAT SINK ASSEMBLY.

POWER MIG 255C