LG LSC27990TT Service Manual page 73

Problems Symptom
Bad cooling Wrong Defective Step Motor
Refrigerator Damper.
temperature.
Defective refrigerator
sensor
Causes
Check Step Motor Check if Step Motor damper
damper motor and motor and reed switch lead
reed switch and lead wire are cut with a tester.
wire are cut. Check Refer to Step Motor damper
Step Motor damper in parts repair guide.
part.
Check Step Motor Refer to Step Motor damper
damper Motor driving in parts repair guide.
relay in PCB.
Foreign materials in Step Check Step Motor damper
Motor damper baffles. baffle visually.
Ice formation on Check if Step Motor damper
Step Motor damper Heater wire is cut with a
baffles. tester.
Defective refrigerator Check the resistance of
sensor parts. refrigerator sensor with a tester. sensor.
Refrigerator sensor is Check the sensor color in the
substituted for other circuit. (Main PCB sensor
sensor. housing.)
Defective refrigerator Check if refrigerator sensor
sensor assembly is not attached at cover sensor but
condition. inner case visually.
Checks Measures
Reconnect lead
wire.
Replace Step Motor
damper or refrigerator
control box Assembly.
Replace relay or
PCB.
Remove foreign
materials.
Replace Step Motor
damper or refrigerator
control Box Assembly.
Replace refrigerator
Repair main PCB
sensor housing.
Re-attach again the
refrigerator sensor.
Remarks
Refer to single
motor damper
driving circuits
in circuit
explanation.
Refer to sensor
resistance
characteristic
table in circuit
explanation.