LG MB-387W Service Manual - Page 21

COMPONENTS TEST PROCEDURE Disconnect the 8 pin connector from P.C.B. (Refer to schemetic diagram) Check for P.C.B. connector. 13 5 RESULTS Cooking Start OFF RELAY 2, RELAY 3 OF P.C.B. (Wire leads removed.) Note: Relay Relay 1: Fan motor Turntable motor Oven lamp Relay 2: Microwave Relay 3: Grill FAN MOTOR (Wire leads removed) Relay 3 Relay 1 Relay 2 Measure the resistance. (Ohm-meter scale: R x 100) TURNTABLE MOTOR (Wire leads removed) A B C Measure the resistance. (Ohm-meter scale: R x 1000) Cooking Start OFF Normal: A ~ B 40 ~ 60Ω A ~ C 300~500Ω Abnormal: ∞ or several Ω Normal: Approx. 100~200 Ω Abnormal: ∞ or several Ω NOTE : • A MICROWAVE LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS SERVICED FOR ANY REASON. • MAKE SURE THE WIRE LEADS ARE IN THE CORRECT POSITION. • WHEN REMOVING THE WIRE LEADS FROM THE PARTS, BE SURE TO GRASP THE CONNECTOR, NOT THE WIRES. 5-11