Daewoo N230S, Service Manual

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19
(TROUBLE 3) No microwave oscillation even though fan motor rotates.
CONDITION CHECK RESULT
Check continuity of high
voltage capacitor terminals
with wires removed
Continuity
CAUSE
Defective high
voltage trans-
former
REMEDY
Replace
No
microwave
oscillation
Check continuity of high
voltage fuse
Replace high voltage fuse
Continuity
Check continuity of high voltage
rectifier in forward and backward
direction with DC megger
Continuity in
backward
direction
Defective high
voltage rectifier
Replace
Connect megger leads to mag-
netron terminal and magnetron
body
Continuity
Defective mag-
netron
Replace
Check resistance of primary and
secondary coil of high voltage
transformer
0
Ω
or
∞
Defective high
voltage trans-
former
Replace
Check continuity of magnetron
with wires removed
No
Continuity
Defective mag-
netron
Replace
Check continuity of filament termi-
nal of high voltage transformer
No
Continuity
Defective high
voltage trans-
former
Replace
Check D.C. voltage being sup-
plied to RELAY (RY1) coil
0 V
Defective touch
control circuit
Replace
Approx
15 VDC
Faulty
contacts or
RELAY (RY1)
or open
relay coil
Replace