LG LSC27990TT Service Manual page 75

Problems Symptom
Defective Buzzer does Trouble mode indication.
display button. not sound
and buttons
do not operate.
Door Buzzer Buzzer Defective connecting lead wire from
continuously main PCB to door switch.
rings or door Defective freezer compartment door
opening alarm switch parts.
does not work.
Defective Ice and water Defective connecting lead wire from
water / ice are not Main PCB to lever switch.
dispenser. dispensed. Defective lever switch parts
Defective photo coupler IC parts.
Defective relay associated with ice
dispenser (geared motor, cube, and
dispenser solenoid).
Defective parts associated with ice
dispenser (geared motor, cube, and
dispenser solenoid).
Defective relay associated with water
dispenser.
Defective parts associated with water
dispenser.
Causes
Check trouble diagnosis function.
Check lead wire associated with door
switch.
Refer to door switch in parts repair
guide.
Check Lead Wire associated with lever
switch with a tester.
Refer to door switch in parts repair guide. Replace lever switch.
Check voltage change at photo coupler
output terminals with lever switch
pressed. It is OK if voltage change is
between 0V - 5V.
Check relay (RY4, RY5, RY12)
with a tester.
Check resistance of parts with a tester.
Check relay (RY7) with a tester
Check resistance of parts with a tester.
Checks Measures
Repair troubles
Repair lead wire.
Replace Freezer
compartment door
switch.
Repair lead wire.
Replace photo
coupler IC or PCB.
Replace defective
relay.
Replace defective
parts.
Replace defective
relay.
Replace defective
parts.
Remarks
Refer to mode
indication in
function
explanations.
Check model
with dispenser.