SAMSUNG M197DFR Service Manual Troubleshooting
6. Troubleshooting
PRECAUTION
1.CHECK GROUNDING BEFORE CHECKING FOR TROUBLE.
2.BE CAREFUL OF THE HIGH VOLTAGE CIRCUIT.
3.DISCHARGE THE HIGH VOLTAGE CAPACITOR.
4.WHEN CHECKING THE CONTINUITY OF THE SWITCHES OR TRANSFORMER, DISCONNECT ONE LEAD WIRE FROM THESE PARTS AND THEN CHECK CONTINUITY WITHOUT THE POWER SOURCE ON. TO DO OTHERWISE MAY RESULT IN A FALSE READING OR DAMAGE TO YOUR METER.
5.DO NOT TOUCH ANY PART OF THE CIRCUIT OR THE CONTROL CIRCUIT BOARD, SINCE STATIC DISCHARGE MAY DAMAGE IT. ALWAYS TOUCH GROUND WHILE WORKING ON IT TO DISCHARGE ANY STATIC CHARGE BUILT UP.
6-1 Electrical Malfunction
SYMPTOM |
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CAUSE |
CORRECTIONS |
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Oven is dead. Fuse is OK. |
1. Open or loose lead wire harness |
Check fan motor when thermal |
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No display and no operation |
2. Open thermal cutout (Magnetron) |
cutout is defective. |
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at all . |
3. Open low voltage transformer |
Check Ass’y PCB when L.V.T is |
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4. |
Defective Ass’y PCB |
defective. |
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No display and no operation |
1. Shorted lead wire harness |
Check adjustment of primary, inter- |
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at all. Fuse is blown. |
2. Defective primary latch switch (NOTE 1) |
lock monitor, |
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3. |
Defective monitor switch (NOTE1) |
power relay, door sensing switch. |
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4. |
Shorted H.V.Capacitor |
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5. |
Shorted H.V.Transformer (NOTE2) |
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NOTE 1: All of these switches must be replaced at the same time. |
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(refer to adjustment instructions) |
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Check continuity of power relay contacts and if it has continuity, re- |
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place power relay also. |
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NOTE 2: When H.V.Transformer is replaced, check diode and magnetron also. |
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Oven does not accept |
1. Key input is not in-Sequence |
Refer to operation procedure. |
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key input (Program) |
2. Open or loose connection of membrane |
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key pad to Ass’y PCB |
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3. |
Shorted or open membrane panel |
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4. |
Defective Ass’y PCB |
Replace PCB main. |
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Timer starts countdown but |
1. Off-alignment of latch switches |
Adjust door and latch switches. |
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no microwave oscillation. |
2. Open or loose connection of high volt- |
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(No heat while oven lamp |
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age circuit especially magnetron fila- |
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and fan motor turn on.) |
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ment circuit |
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NOTE: Large contact resistance will bring |
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lower magnetron filament voltage |
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and cause magnetron to lower out- |
Check high voltage component ac- |
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put and/or intermittent oscillation. |
cording to component test proce- |
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3. |
Defective high voltage components |
dure and replace if it is |
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H.V.Transformer H.V.Capacitor |
defective. |
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H.V.Diode, H.V.Fuse Magnetron |
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4. |
Open or loose wiring of power relay |
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5. |
Defective primary latch switch |
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6. |
Defective power relay or Ass’y PCB |
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Replace PCB main. |
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- 13 -
6-1 Electrical Malfunction(continued)
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SYMPTOM |
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CAUSE |
CORRECTIONS |
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Oven lamp and fan motor |
1. |
Misadjustment or loose wiring of pri- |
Adjust door and latch switches. |
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turn on |
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mary latch switch |
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2. |
Defective primary latch switch |
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Oven can program but timer |
1. |
Open or loose wiring of secondary |
Adjust door and interlock switches. |
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does not start. |
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interlock switch |
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2. |
Off-alignment of primary interlock |
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3. |
Defective secondary interlock S/W |
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Microwave output is low;. |
1. |
Decrease in power source voltage. |
Consult electrician. |
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Oven takes longer time to |
2. |
Open or loose wiring of magnetron fila- |
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cook food. |
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ment circuit. (Intermittent oscillation) |
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3. Aging of magnetron |
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Fan motor turns on when |
Loose wiring of door sensing switch |
Check wire of door sensing switch. |
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plugged in |
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Oven does not operate and |
Defective Ass’y PCB |
Replace PCB main. |
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return to the plugged in |
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mode. |
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Loud buzzing noise can be |
1. |
Loose fan and fan motor |
Tighten screws of fan motor. |
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heard. |
2. |
Loose screws on H.V.Transformer |
Tighten screws of H.V.Transformer. |
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3. |
Shorted H.V.Diode |
Replace H.V.Diode. |
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Turntable motor does not |
1. |
Open or loose wiring of turntable motor. |
Replace turntable motor. |
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rotate. |
2. |
Defective turntable motor. |
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Oven stops operation dur- |
1. |
Open or loose wiring of primary inter- |
Adjust door and latch switches. |
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ing cooking |
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lock switch |
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2. Operation of thermal cutout(Magnetron) |
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Sparks |
1. |
Metallic ware or cooking dishes touch- |
Inform the customer. |
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ing on the oven wall. |
Do not use any type of cookware |
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2. |
Ceramic ware trimmed with gold or |
with metallic trimming. |
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silver powder also causes sparks. |
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Uneven cooking |
Uneven intensity of microwave due to its |
Wrap thinner parts of the food with |
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characteristics. |
aluminum foil.Use plastic wrap or |
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cover with a lid.Stir once or twice |
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while cooking foods such as soup, |
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cocoa, or milk. |
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Noise from the turntable |
Noise may result from the motor. |
Replace turntable motor. |
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motor when it starts to oper- |
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ate. |
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Radio Voice does not sound |
1. |
Problem of the Speaker |
1. Replacing the Speaker |
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2. |
Defect of Contacting with Connecter |
2. Check the contacting point of |
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3. |
Problem of internal material in Tuner |
Connecter |
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3. Replacing the Tuner ass’y |
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Voice Recorder does not |
1. |
Problem of the Speaker |
1. Replacing the Speaker |
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work |
2. |
Defect of Contacting with Connecter |
2. Check the contacting point of |
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3. |
Problem of internal material in Tuner |
Connecter |
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3. Replacing the Tuner ass’y |
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