LG MAB745W 01 Service Manual - Page 19

COMPONENT TEST PROCEDURE CAUTIONS 1. DISCONNECT THE POWER SUPPLY CORD FROM THE OUTLET WHENEVER REMOVING THE OUTER CASE FROM THE UNIT. PROCEED WITH THE TEST ONLY AFTER DISCHARGING THE HIGH VOLTAGE CAPACITOR AND REMOVING THE WIRE LEADS FROM THE PRIMARY WINDING OF THE HIGH VOLTAGE TRANSFORMER. (SEE PAGE 2-1) 2. ALL OPERATIONAL CHECKS WITH MICROWAVE ENERGY MUST BE DONE WITH A LOAD (1 LITER OF WATER IN CONTAINER) IN THE OVEN. COMPONENTS TEST PROCEDURE RESULTS HIGH VOLTAGE TRANSFORMER (Wire leads removed) FILAMENT WINDING TERMINAL MAGNETRON (Wire leads removed) SECONDARY TERMINAL PRIMARY TERMINAL 1. Measure the resistance. (Ohm-meter scale: Rx1 and Rx100) • Primary winding • Secondary winding • Filament winding 2. Measure the resistance. (Ohm-meter scale: Rx1000) • Primary winding to ground • Filament winding to ground 1. Measure the resistance. (Ohm-meter scale: Rx1) • Filament terminal 2. Measure the resistance. (Ohm-meter scale: Rx1000) • Filament to chassis Approx.: 0.3 ~ 0.8 ohm Approx.: 100 ~ 200 ohm Less than: 1 ohm Normal: Infinite Normal: Infinite Normal: Less than 1 ohm Normal: Infinite 5-8