LG LSC27990TT Service Manual page 72

Problems Symptom
Bad cooling. Freezer Compressor does
temperature is not start.
high.
Defective freezer
sensor.
Defective freezer fan
motor.
Faulty defrost.
Causes
Compressor Lead Wire Check compressor Lead Wire
is cut. with a tester.
Defective compressor Measure voltage at PCB CON2 Replace relay RY1
driving relay. (3 & 9) after pressing main PCB and RY2 or PCB.
test switch once. It is OK if
voltage is normal.
Defective Freezer Check resistance of freezer
sensor parts. sensor with a tester.
The wrong sensor Confirm the color of sensor in
has been installed. circuits (main PCB sensor
Order by model number housing).
and part number.
Fan motor lead wire Check fan motor lead wire
is cut. with a tester.
• Defective door switch Measure the voltage between
(freezer, refrigerator, PCB power blue line and fan
home bar). motor after pressing test switch
• Defective fan motor. of Main PCB. If the voltage is
• Defective fan motor normal, it is OK.
driving relay.
Refer to faulty defrost items in trouble diagnosis
functions.
Checks Measures
Reconnect Lead
Wire.
Replace freezer
sensor.
Repair main PCB
sensor housing
Reconnect lead
wire.
• Replace door
switch (freezer,
refrigerator, and
home bar).
• Replace fan motor.
• Replace relay RY5
& RY6 or PCB.
Remarks
Refer to load
driving circuit in
circuit
explanation.
Refer to
resistance
characteristics
table of sensor in
circuit. Refer to
tables on pages
39~42
explanation.
Refer to load
driving circuits in
circuit
explanation.
Refer to trouble
diagnosis
function.