Lincoln Electric IDEALARC DC-655 Service Manual page 78

F-36
FIGURE F.14 – THERMAL FAN/SNUBBER BOARD AND FIRING BOARD PLUG LOCATIONS
THERMAL FAN / SNUBBER
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.
TROUBLESHOOTING & REPAIR
STATIC SCR TEST (continued)
L10124-[ ]
LED2
LED6
LED5
LED4
LED1
LED3
LED7 LED8 LED9
LED1 LED2
LED3 LED4
LED6
LED5
IDEALARC DC-655
PLUG J9
J5
G2699-[ ]
J6
LED10
J4
FIRING BOARD
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.
J7
F-36