LG MAB745W 01 Service Manual - Page 24

(TROUBLE 2) Oven does not operate at all, Display window does not display any figures, and no input is accepted. CONDITION 1. Fuse blows. CHECK Check continuity of monitor switch (with door closed). Replace fuse RESULT Continuity. No continuity. CAUSE Malfunction of the monitor switch. REMEDY Replace fuse, primary, monitor, secondary switches, and RELAY(RY2) of P.C.B Assembly. Check continuity of primary switch (with door opened) Disconnect one side of the wire lead connected from transformer to the high voltage capacitor and operate the unit. Continuity. No continuity. Normal. Fuse blows again Shorted contact at the primary switch. Defective high voltage capacitor. Defective high voltage transformer. Replace fuse, primary, monitor, secondary switches, and RELAY(RY2) of P.C.B Assembly. Replace high voltage capacitor. Replace high voltage transformer. NOTE : All these switches must be replaced at the same time. Refer to page 5-7, 5-8 2. Fuse does not blow. Check continuity of thermostat. No continuity. Continuity. Defective thermostat. Replace thermostat. Check continuity of power supply cord. No continuity. Defective power supply cord. Replace power supply cord. 5-13