Samsung SMH7174WE Service Manual page 27

6-1 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.
Display error1
Display error2
Display error3
Display error4
CAUSE
1. Misadjustment or loose wiring
of primary latch switch
2. Defective primary latch switch
1. Open or loose wiring of secondary i
nterlock 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.
Shorted sensor's circuit.
Open sensor's circuit.
On the cooling mode, sensor's Vout was
not less than 4.7V within 3minutes.
On the way to sensing, the door was open.
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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.
Let oven cool for at least 5minutes.
Check connection of the sensor if
the sensor's circuit was shorted or
not by the alien substance.
Check connection of sensor's wire.
Let oven cool for at least 5minutes.
Press the 'pause/cancel'pad, and
then you have to do all over again.