Frigidaire PLMV178HC Service Manual page 26

7-1 Electrical Malfunction (Continued)
SYMPTOM
Oven lamp and fan motor turn
on
Oven can program but timer
does not start.
Microwave output is low:
Oven takes longer time to
cook food.
Fan motor turns on when
plugged in
Oven does not operate and
return to the plugged in mode.
Loud buzzing noise can be
heard.
Turntable motor does not
rotate.
Oven stops operation during
cooking
Sparks
Uneven cooking
Noise from the turntable motor
when it starts to operate.
CAUSE
1. Misadjustment or loose wiring of primary
latch switch
2. Defective primary latch switch
1. Open or loose wiring of secondary interlock
switch
2. Off-alignment of primary interlock
3. Defective secondary interlock S/W
1. Decrease in power source voltage.
2. Open or loose wiring of magnetron filament
circuit. (Intermittent oscillation)
3. Aging of magnetron
Loose wiring of door sensing switch
Defective Ass'y PCB
1. Loose fan and fan motor
2. Loose screws on H.V.Transformer
3. Shorted H.V.Diode
1. Open or loose wiring of turntable motor.
2. Defective turntable motor.
1. Open or loose wiring of primary interlock
switch
2. Operation of thermal cutout(Magnetron)
1. Metallic ware or cooking dishes touching on
the oven wall.
2. Ceramic ware trimmed with gold or silver
powder also causes sparks.
Uneven intensity of microwave due to its
characteristics.
Noise may result from the motor.
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CORRECTIONS
Adjust door and latch switches.
Adjust door and interlock switches.
Consult electrician.
Check wire of door sensing switch.
Replace PCB main.
Tighten screws of fan motor.
Tighten screws of H.V.Transformer.
Replace H.V.Diode.
Replace turntable motor.
Adjust door and latch switches.
Inform the customer.
Do not use any type of cookware with
metallic trimming.
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.
Replace turntable motor.