Heat sink test points. see figure f.15. do, Anode to the cathode of scr1. see figure f.15, The meter leads. see figure f.15 – Lincoln Electric IDEALARC DC-655 User Manual
Page 79: Troubleshooting & repair, Static scr test (continued)
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6.
If a high or infinite resistance is indicated for
both steps #4 and #5, SCR1 is not shorted.
7.
If a low resistance is indicated in either steps
#4 or #5, there is a shorted SCR in the out-
put rectifier bridge. Repeat steps #4 and #5
for each of the six SCRs. It may be neces-
sary to disconnect the transformer sec-
ondary leads from the rectifier assembly to
isolate the defective SCR(s). See the Wiring
Diagram.
8.
Replace plug J9 into the thermal fan/snub-
ber board and plug J5 into the firing board.
NOTE: To further check the SCRs’ functions use
an SCR tester and proceed to the Active SCR
Test.
TROUBLESHOOTING & REPAIR
F-37
F-37
IDEALARC DC-655
STATIC SCR TEST (continued)
FIGURE F.15 – HEAT SINK TEST POINTS
ANODE
CATHODE
REMOVE
INSULATING
PAINT
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