Samsung ME21F707MJT Service Manual page 31

5. Troubleshooting
Timer starts countdown but no microwave oscillation.
(No heat while oven lamp and fan motor turn on.)
Timer starts
countdown but
no microwave
oscillation
Oven can program but timer does not start.(A message of "Close Door" appears on the display.)
Oven can program
but timer does not start
(A message of "Close Door"
appears on the display.)
Microwave output is low. (Oven takes longer time to cook food.)
Microwave
output is low
Fan motor turns on when plugged in.
Fan motor turns
on when plugged in
Oven does not operate and return to the plugged in mode.
Oven does not
operate and return to
the plugged
in mode
Off-alignment of latch switches
Open or loose connection of high
voltage circuit especially magnetron
filament circuit
(NOTE)
Defective high voltage components
H.V.Transformer H.V. Capacitor
H.V.Diode, H.V.Fuse Magnetron
Open or loose wiring of power relay
Defective primary latch switch
Defective power relay or Ass'y PCB
NOTE: Large contact resistance will bring lower magnetron filament voltage and cause magnetron
to lower output and/or intermittent oscillation.
Open or loose wiring of secondary
interlock switch
Off-alignment of primary interlock
Defective secondary interlock S/W
Decrease in power source voltage
Open or loose wiring of magnetron
filament circuit.
(Intermittent oscillation)
Aging of magnetron
Loose wiring of door sensing switch
Defective Ass'y PCB
31
Adjust door and latch switches.
Check high voltage component according to
component test procedure and replace if it is
defective.
Replace PCB main.
Adjust door and interlock switches.
Consult electrician.
Tighten door sensing switch wiring.
Replace PCB main.