LG LMH2235ST, Service Manual

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10. COMPONENT TESTING INFORMATION
CAUTION
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 LEAD WIRES FROM THE PRIMARY WINDING OF THE HIGH VOLTAGE TRANSFORMER.
2. ALL OPERATIONAL CHECKS WITH MICROWAVE ENERGY MUST BE DONE WITH A LOAD (1 LITER OF
WATER IN CONTAINER) IN THE OVEN.
A. TEST PROCEDURES
TRANSFORMER
MAGNETRON
1. Remove wire leads.
2. Measure resistance. (ohm meter scale: Rx1)
• Primary winding
• Secondary winding
• Filament winding
3. Measure resistance. (ohm meter scale: Rx1000)
• Primary winding to ground
• Filament winding to ground
1. Remove wire leads. Install the magnetron seal in
the correct position. Check that the seal is in
good condition.
2. Measure resistance. (ohm meter scale: Rx1)
• Filament terminal
3. Measure resistance. (ohm meter scale: Rx1000)
• Filament to chassis
Normal: Less than 1 ohm
Normal: Infinite
COMPONENTS TEST RESULTS
SECONDARY
WINDING
PRIMARY
WINDING
FILAMENT
WINDING
Approx. 0.3 to 0.5 ohms
Approx. 65 to 120 ohms
0 ohm
Normal: Infinite
Normal: Infinite
Filament
Antenna
Gasket
Chassis