LG LTM9020B, Service Manual

Page: 24 / 43

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B. CHECKOUT PROCEDURES
(1) CHECKOUT PROCEDURES FOR FUSE BLOWING
CAUTION: REPLACE BLOWN FUSE WITH 15 AMPERE FUSE.
Fuse blows immediately after
the door is closed.
Fuse blows immediately after
the door is opened.
Fuse blows when the door is closed and START key
is touched.
Improper operation of the primary interlock,
secondary interlock switches and/or the interlock
monitor switch.
Malfunction of the high voltage transformer; the high
voltage capacitor including the diode, the magnetron,
the blower motor or the circuit board.
PROBLEMS CAUSES
NOTES:
- If the fuse is blown by an improper switch operation, replace the defective switches and the fuse at the same time.
After replacing the defective switches with new ones, make sure that they are correctly connected.
- Check for microwave energy leakage according to “1. ADJUSTMENT PROCEDURES” on page 3, when the
primary interlock, secondary interlock switches and/or the interlock monitor switches are adjusted or replaced.