LG CM4520 Service Manual

4. FLD DISPLAY CHECK
FLD DISPLAY CHECK
OK
YES
Check
CN105 Pin1,2,3 input
voltage.
YES
Check if both end voltage
of FL+, FL- are over 2.9 V
VKK : over 25.6 V.
NO
Refer to SMPS troubleshooting.
YES
Check CN501
connection and power
Pin1, 2, 3(FL+, FL-, VKK),
Pin10(3.7 VA).
YES
OK
NO
Check CN501 connection.
YES
Check each
Pin voltage.
YES
Check
IC501(ET16315) voltage
Pin30 VKK: -25.8 V
Pin13, 43: 3.4 V.
YES
Check
IC102->IC501
data communication
Pin3->Pin9 STB
Pin2->Pin7 DATA
Pin4->Pin8 CLK
FLD light on?
OK
NO
If voltage is not 3.4 VA, check input
and output of D502 and D503.
YES
Check IC501.
YES
NO
Replace IC501.
NO
Check input data
IC102 Pin2,3,4.
YES
OK
Check IC102.
YES
NO
Replace IC102.
Check output data IC102 Pin2.
YES
YES
YES
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AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE

LG CM4520 Specifications

General

Brand	LG
Model	CM4520
Category	Stereo System
Language	English