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6-1 Electrical Malfunction (continued)
SYMPTOM
CAUSE
CORRECTIONS
Oven lamp and fan motor
turn on
1. Misadjustment or loose wiring
of primary latch switch
2. Defective primary latch switch
Adjust door and latch switches.
Oven can program but timer
does not start.
1. Open or loose wiring of secondary i
nterlock switch
2. Off-alignment of primary interlock
3. Defective secondary interlock S/W
Adjust door and interlock switches.
Microwave output is low;.
Oven takes longer time to
cook food.
1. Decrease in power source voltage.
2. Open or loose wiring of magnetron
filament circuit. (Intermittent oscillation))
3. Aging of magnetron
Consult electrician.
Fan motor turns on when
plugged in
Loose wiring of door sensing switch
Check wire of door sensing switch.
Oven does not operate and
return to the plugged in
mode.
Defective Ass’y PCB
Replace PCB main.
Loud buzzing noise can be
heard.
1. Loose fan and fan motor
2. Loose screws on H.V.Transformer
3. Shorted H.V.Diode
Tighten screws of fan motor.
Tighten screws of H.V.Transformer.
Replace H.V.Diode.
Turntable motor does not
rotate.
1. Open or loose wiring of turntable motor.
2. Defective turntable motor.
Replace turntable motor.
Oven stops operation during
cooking
1. Open or loose wiring of primary interlock
switch
2. Operation of thermal cutout (Magnetron)
Adjust door and latch switches.
Sparks
1. Metallic ware or cooking dishes touching on
the oven wall.
2. Ceramic ware trimmed with gold or silver
powder also causes sparks.
Inform the customer.
Do not use any type of cookware with
metallic trimming.
Uneven cooking
Uneven intensity of microwave due to its
characteristics.
Wrap thinner parts of the food with
aluminum foil.
Use plastic wrap or cover with a lid. Stir
once or twice while cooking foods such
as soup, cocoa, or milk.
Noise from the turntable
motor when it starts to
operate.
Noise may result from the motor.
Replace turntable motor.
