8.2. (Troubleshooting) Other problems
SYMPTOM
CAUSE
CORRECTIONS
1. Oven is dead.
1. Open or loose lead wire harness
Fuse is OK.
2. Open thermal cutout / thermistor
Check thermal cutout is defective.
No display and no operation at all.
3. Open low voltage transformer
4. Defective DPC
2. No display and no operation at all.
Fuse is blown.
1. Shorted lead wire harness
Check adjustment of primary, secondary
interlock switch and monitor switch including
door.
2. Defective primary interlock switch (NOTE 1)
3. Defective monitor switch (NOTE 1)
4. Defective Inverter Power Supply (U)
NOTE 1:
All of these switches must be replaced at the same time.
Check continuity of power relay RY1 contacts (between 1 and 2) and if it has continuity, replace
power relay RY1 also.
3. Oven does not accept key input
(Program)
1. Key input is not in proper sequence
Refer to operation procedure.
2. Defective DPC or defective membrane switch Refer to DPC troubleshooting.
4. Fan motor turns on when oven is
plugged in with door closed.
1. Misadjustment or loose wiring of secondary
interlock switch
Adjust door and interlock switches.
2. Defective secondary interlock switch
3. Door switch CN4
5. Timer starts count down but no
microwave oscillation.
(No heat while oven lamp and fan
motor turn on)
1. Off-alignment of primary interlock switch
Adjust door and interlock switches.
2. Open or loose connection of high voltage
circuit especially magnetron filament circuit
NOTE:
Large contact resistance will cause lower
magnetron filament voltage and cause
magnetron to have lower output and/or be
intermittent.
3. Defective high voltage component
H.V. Inverter Power Supply (U)
Magnetron
Check high voltage component according to
component test procedure and replace if it is
defective.
4. Open or loose wiring of power relay RY1
5. Defective primary interlock switch
6. Defective DPC or power relay RY1
Refer to DPC troubleshooting
6. Oven can program but timer does not
start countdown.
1. Open or loose wiring of secondary interlock
switch
2. Off-alignment of secondary interlock switch
3. Defective secondary interlock switch
7. Microwave output is low. Oven takes
longer time to cook food.
1. Decrease in power source voltage
Consult electrician
2. Open or loose wiring of magnetron filament
circuit.(Intermittent oscillation)
3. Aging change of magnetron
8. Fan motor turns on and turntable
motor rotates when door is opened.
1. Low voltage transformer on DPC.
9. Oven does not operate and return to
plugged in mode as soon as [Start]
pad is pressed.
1. Defective DPC
Check grounding connector on escutcheon
base.
10. Loud buzzing noise can be heard.
1. Loose fan and fan motor
11. Turntable motor does not rotate.
1. Open or loose wiring of turntable motor
2. Defective turntable motor
12. Oven stops operation during cooking.
1. Open or loose wiring of primary and
secondary interlock switch
Adjust door and interlock switches.
2. Operation of thermal cutout
23
NN-SD691S / NN-ST681S / NN-SD671S / NN-ST671S / NN-ST661S / NN-ST661B / NN-ST661W / NN-ST651B / NN-ST651W
Summary of Contents for Inverter NN-ST651W
Page 2: ...2 NN SD691S NN ST681S NN SD671S NN ST671S NN ST661S NN ST661B NN ST661W NN ST651B NN ST651W ...
Page 3: ...3 NN SD691S NN ST681S NN SD671S NN ST671S NN ST661S NN ST661B NN ST661W NN ST651B NN ST651W ...
Page 38: ...38 NN SD691S NN ST681S NN SD671S NN ST671S NN ST661S NN ST661B NN ST661W NN ST651B NN ST651W ...
Page 40: ...40 NN SD691S NN ST681S NN SD671S NN ST671S NN ST661S NN ST661B NN ST661W NN ST651B NN ST651W ...
