Samsung MW5490W Service Manual - Page 16

Troubleshooting 6-2 Electrical Mulifunction(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 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 from the turntable motor when it starts to operate. Noise may result from the motor. 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. Check the wire of turntable motor. 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. 6-2 Samsung Electronics