LG LMV1925SB, Service Manual

Page: 33 / 46

7-22
PROBLEM - C:
Display does not start countdown when ST
AR
T
key is touched.
PROBLEM - D:
Unit
operation
seems
to
be
normal
but
little
or
no heating is produced in oven load.
Check: 1.
T
OUCH KEY
BOARD (ST
AR
T
KEY
FUNCTION)
Check: 1.
AIR VENTS
1
1
Check continuity of connector CN2 between Pin 1(PK) and pin 3(BL) when the door is closed
Check operation of fan motor when ST
AR
T
key
is touched.
Continuity
OK
Check contact of
connector S1
Contact
OK
Replace
Circuit board
Correct seating
Normal
circuit board
Normal contact
Poor
contact
Normal Primary
switch
No
continuity
Adjust or replace door
sensing switch.
Measure resistance
of H.V.capacitor
(see page 7-16)
Resistance
incorrect
Normal
resistance
Measure resistance
of fan motor
T
erminal
A~C: 140 to 150 ohm
T
erminal
A~B: 25 to 40 ohm
Resistance
incorrect
Replace
fan motor
Normal
circuit board
Replace
Normal fan motor
circuit board
Normal
resistance
Replace H.V.C.
Normal H.V.C.
Normal
magnetron
Replace
magnetron
Normal
operation
No
operation
Runs
Runs
Runs
Runs Runs
Runs
Runs
33