LG MS1440SL Service Manual page 23

(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.
LGE Internal Use Only
CHECK
Check continuity
of monitor
switch (with
door closed).
Replace fuse
Check continuity
of primary
switch (with
door opened).
Check continuity
of secondary
switch (with
door opened).
Disconnect one
side of the wire
lead connected
from transformer
to the high
voltage
capacitor and
operate the unit.
Check continuity
of thermostat.
Continuity.
Check continuity
of power supply
cord.
RESULT
Malfunction of the
Continuity.
monitor switch.
No continuity.
Continuity.
Shorted contact at
the primary switch.
No continuity.
Continuity.
Malfunction of
secondary switch.
No continuity.
Defective high
Normal.
voltage capacitor.
Defective high volt-
Fuse blows again
age transformer.
Defective
No continuity.
thermostat.
Defective power
No continuity.
supply cord.
5-13
CAUSE
Replace fuse,
primary, monitor
secondary
switches, and
RELAY(RY2) of
P.C.B Assembly.
Replace fuse,
primary, monitor
secondary
switches, and
RELAY(RY2) of
P.C.B Assembly.
Replace fuse,
primary, monitor,
secondary
switches, and
RELAY(RY2) of
P.C.B Assembly.
Replace high
voltage capacitor.
Replace high volt-
age transformer.
Replace
thermostat.
Replace power
supply cord.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
REMEDY