Troubleshooting & repair, Static scr test (continued), Test procedure – Lincoln Electric IDEALARC DC-655 User Manual
Page 78
TROUBLESHOOTING & REPAIR
F-36
F-36
IDEALARC DC-655
STATIC SCR TEST (continued)
FIGURE F.14 – THERMAL FAN/SNUBBER BOARD AND FIRING BOARD PLUG LOCATIONS
THERMAL FAN / SNUBBER
LED5
LED1
LED2
LED3
LED4
LED6
PLUG J9
L10124-[ ]
FIRING BOARD
G2699-[ ]
LED7
LED8
LED9
LED1
LED2
LED3
LED4
LED5
LED6
LED10
J5
J6
J7
J4
TEST PROCEDURE
1.
Disconnect the main AC input power to the
DC-655 machine.
2.
Locate and disconnect plug J9 from the
thermal fan/snubber board and plug J5 from
the firing board. See Figure F.14.
3.
Remove the red insulating paint from the
heat sink test points. See Figure F.15. DO
NOT DISASSEMBLE THE HEAT SINKS.
4.
Test for high or infinite resistance from the
anode to the cathode of SCR1. See Figure
F.15. Use an analog ohmmeter (multimeter).
5.
Test for high or infinite resistance from the
cathode to the anode of SCR1 by reversing
the meter leads. See Figure F.15.