Daewoo KOG-8B5R5S, Service Manual, Page: 22 / 38

21
(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
transformer
REMEDY
Replace No
microwave
oscillation
Check continuity of high voltage
diode in forward and backward
direction with DC megger
Continuity in
backward
diode
Defective high
voltage diode
Replace
Connect megger leads to
magnetron terminal and
magnetron body
Continuity
Defective
magnetron
Replace
Check resistance of primary and
secondary coil of high voltage
transformer
0
Ω
or
∞
Defective high
voltage
transformer
Replace
Check continuity of magnetron
with wires removed
No
Continuity
Defective
magnetron
Replace
Check continuity of filament
terminal of high voltage
transformer
No
Continuity
Defective high
voltage
transformer
Replace
Check D.C. voltage being
supplied to RELAY (RY1) coil
0 V
Defective touch
control circuit
Replace
Approx
15 VDC
Faulty contacts of
RELAY (RY1) or
open relay coil
Replace