Samsung m965ce Service Manual & Spare Parts List page 15

Troubleshooting
6-1 Electrical Maltunction(continved)
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.
6-3 Gas Sensor
AUTO COOK (SENSOR ONLY)
The Auto Cook function uses a special gas sensor which detects
both humidity (steam) and hydrocarbons (food odors) during the
cooking process.
The sensor is a plug-in device located on the left side of the
cavity at the cavity exhaust.
RETAINER
HEATER
LEADS
6-2
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.
SENSOR
RECEPTACLE
SENSOR
LEADS
TUBING
DOOR
CAUSE
AUTO COOK TEST (SENSOR ONLY)
1. Place 1/3 cup tap water in oven.
2. Touch POPCORN
3. After 1-2 mins: Control Beeps & Display counts down.
4. Touch CLEAR OFF.
A) Test OK-Normal
B) Test Fails-Check Sensor (See Sensor Test)
SENSOR TEST(QUICK TEST) (SENSOR ONLY)
1. With 2-fingers touch and hold the following pads at the same time : 7
and 8
2. Observe diagnostic number in display(numbers approximate)
* 15-185(Normal-verify with "detection test")
* 185 or Higher(sensor failed open. sensor unplugged,
wiring, or smart board)
* Less than 15 (shorted sensor, or smart board)
NOTE : Only heater terminals (H) can be checked with ohmmeter (30½)
CAUTION : DO NOT ATTEMPT TO CHECK
SENSOR TERMINALS(CAN DAMAGE SENSOR).
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.
Samsung Electronics