LG LRM1250W 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.
NOTE : All these switches must be replaced at the same time. Refer to page 5-7, 5-8
2. Fuse does not
blow.
CHECK
Check continuity
Continuity.
of monitor
switch (with
door closed).
No continuity.
Replace fuse
Check continuity
Continuity.
of primary
switch (with
door opened)
No continuity.
Check continuity
Continuity.
of secondary
switch (with
door opened).
No continuity.
Disconnect one
Normal.
side of the wire
lead connected
from transformer
Fuse blows again
to the high
voltage
capacitor and
operate the unit.
No continuity.
Check continuity
of thermostat.
Check continuity
of power supply
cord.
RESULT
Continuity.
No continuity.
5-13
CAUSE
Malfunction of the Replace fuse,
monitor switch.
primary, monitor,
secondary
switches, and
RELAY(RY2) of
P.C.B Assembly.
Replace fuse,
Shorted contact at
primary, monitor,
the primary switch.
secondary
switches, and
RELAY(RY2) of
P.C.B Assembly.
Replace fuse,
Malfunction of
primary, monitor,
secondary switch.
secondary
switches, and
RELAY(RY2) of
P.C.B Assembly.
Defective high Replace high
voltage capacitor. voltage capacitor.
Defective high volt- Replace high volt-
age transformer. age transformer.
Defective
thermostat.
Defective power
supply cord.
REMEDY
Replace
thermostat.
Replace power
supply cord.