Lincoln Electric IDEALARC CV-300 Service Manual page 60

F-21
ACTIVE SCR RECTIFIER ASSEMBLY TEST (CONTINUED)
10. Close switch SW-1.
NOTE: Switch SW-2 should be open.
11. Read meter for zero voltage.
a. If the voltage reading is higher
than zero, the SCR is shorted.
12. Close or keep closed switch SW-1.
13. Close switch SW-2 for 2 seconds
and release and read meter.
a. If the voltage is 3 - 6 volts while
the switch is closed and after
the switch is open, the SCR is
functioning.
b. If the voltages is 3-6 volts only
when the switch is closed or
there is no voltage when the
switch is closed, the SCR is
defective.
NOTE: Be sure battery is functioning
properly. A low battery can affect the
results of the test. Repeat Battery Test
Procedure in Step 6 if needed.
14. Open switch SW-1.
15. Reconnect the Tester leads.
Figure F.16.
a. Connect Tester lead (A) to the
cathode.
b. Connect Tester lead (C) to the
anode.
c. Disconnect Test lead (G) from
the gate.
16. Close switch SW-1.
17. Read meter for zero voltage.
a. If the voltage is zero, the SCR is
functioning.
b. If the voltage is higher than
zero, the SCR is shorted.
TROUBLESHOOTING & REPAIR
18. Perform the Active Test Procedure
19. Replace all SCR assemblies that do
20. Replace all disconnected leads and
See
IDEALARC CV-300
outlined in Steps 9-17 for SCR 2.
not pass the above tests.
Molex Plugs.
F-21