LG LMVM2277ST Product Training Manual page 128

Microwave Power
Verify operation or rotation of the waveguide stirrer.
Disconnect power, discharge the high voltage capacitor,
and check the high voltage transformer.
A layer short circuit of the high voltage transformer
may cause a low power output.
If burned places are found in the high voltage
transformer and a smell of burning insulation is
sensed, replace the high voltage transformer.
LMVM2277ST
128
T-37