Samsung M308R Service Manual page 15

6-2 Electrical Maltunction(continved)
SYMPTOM
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.
Oven stops operation during cooking
Sparks
Uneven cooking
Samsung Electronics
CAUSE
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 primary
interlock switch
2. Operation of thermal cutout(Cavity)
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.
Troubleshooting
CORRECTIONS
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.
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.
6-2