LG GoldStar MA-2003B 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
Check continuity
1. Fuse blows.
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.
NOTE : All these switches must be replaced at the same time. Refer to page 5-7, 5-8
2. Fuse does not
Check continuity
blow.
of thermostat.
Check continuity
of power supply
cord.
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CHECK RESULT
Continuity.
No continuity.
Continuity.
No continuity.
Continuity.
No continuity.
Normal.
Fuse blows again
No continuity.
Continuity.
No continuity.
CAUSE
Malfunction of the
monitor switch.
Shorted contact at
the primary switch.
Malfunction of
secondary switch.
Defective high
voltage capacitor.
Defective high volt-
age transformer.
Defective
thermostat.
Defective power
supply cord.
5-13
REMEDY
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.