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SECTION 3. AUDIO
ELECTRICAL PART
AUDIO ELECTRICAL TROUBLESHOOTING GUIDE
1. MICOM PART CHECK I
MICOM PART
HECK I
YES
Check
CN710 7PIN
P- SENS
YES
Is IC101
KIA7042
5V?
YES
Check the IC100
87F5NC8A 4
PIN power
YES YES
OK OK
NO
NO
Refer to SMPS
Troubleshooting.
Is IC101
KIA7042
input 5V?
YES YES
Is IC101 KIA7042
output 4.3V?
NO NO
Check the
related part of IC101
KIA7042
Replace the related
part
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3-1
LGE Internal Use Only
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2. MICOM PART CHECK II
MICOM PART CHECK II
YES
Check CN710
6PIN 5.6V
YES
Check the
power of both
D102 and D101 1SR35
(Is the power of
IC 100,14.40.55
89 4.8V?
YES
Check IC102
KIA7031 input power.
NO
NO
NO
Refer to SMPS
Troubleshooting.
Check the D101,102
1SR35 output 5V
YES
Check the
related part.
YES
OK
Check the D101
1SR35 output 5V
NO
NO
Replace the related parts.
Check & replace the related
part.
Check IC102 KIA7031
output power
Check IC100 87F5NC8A
8 PIN power.
OK OK
LGE Internal Use Only
YES
YES
YES
YES
Check
IC 102 KIA7031
input power (4.8V or input power
(4.8V or higher)
YES
Check IC 102
KIA7031 output
power
YES
3-2
NO
NO
Copyright © 2008 LG Electronics. Inc. All right reserved.
Check R1A9 680 Ω
YES
OK
Check the operation status of
R191 10K and R110 4.7K
YES
Replace the related parts.
Only for training and service purposes
NO
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3. MICOM PART CHECK III
MICOM PART CHECK III
YES
Check the IC100 14.40.56.89
input power (4.8V or higher)
YES
Check the operation
status of
X101:32.768KHz and
X100:9.8304MHz
YES
OK
NO
Refer to MICOM Par I,II Troubleshooting
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3-3
LGE Internal Use Only
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4. FLD DISPLAY PART CHECK
FLD DISPLAY CHECK
YES
Check the power of CN710
10 11 12 PIN
YES
Check
10 PIN → - 27V
11 PIN→ 20V
12 PIN→ 25V
YES
Check the
connecting condition
and the power of P3702
40PIN: FL- 20
39PIN: FL+ 25
38PIN: VKK-28vor higher
39PIN: 5.6V
YES
Check
IC304 PT6324
power 50 PIN VKK:-28V
9.52 PIN +5V
NO
NO
NO
Refer to SMPS
Troubleshooting
Check CN710
assembly
YES
Check each pin
YES
OK
If 5V is failed, check the input and
output power of D319 1SR35
YES
Check the related part
NO
NO
Replace the related part
Replace the related part.
Check IC100 →
IC301 DATA communication
PIN PIN
27 PIN → 3PIN STB
26 PIN → 2PIN D
28 PIN → PIN CLK
FLT turned on
OK
LGE Internal Use Only
YES
YES
YES
NO
YES
OK
IC100 IC303
27 PIN → 3PIN STB
28 PIN → 1PIN CLK
Check Data output
YES
Check the data at both terminals
of LINE R330,331,332
YES
Check the related part
YES
OK
3-4
Copyright © 2008 LG Electronics. Inc. All right reserved.
NO
Replace the related part.
Only for training and service purposes
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5. IC103 S-24CS16A01-J8T1GE CHECK
CHECK IC100
LC87F5NC8A 81,82
YES
81 PIN DATA 82 PIN CLK
YES
NO
NO
Check the communication between
both terminals of R189,190 100Ω
CLK
DAT
Check MICOM power 5V
YES
NO
Refer to micom
troubleshooting.
OK
Check the related part.
YES
OK
NO
Replace the related parts.
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3-5
LGE Internal Use Only
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6. AUX FUNCTION PART CHECK
AUX FUNCTION PART
YES
Make sure that
JK800 is
YES
Check the input
waveform of IC200 (BU4052)
4,11PIN
YES
Check the output waveform of
IC200 (BU4052) 3,13PIN
YES
Check the input
waveform of IC801
(MC4580) 2,6PIN
YES
Check the output
waveform of the PN709
6 PIN L_ CH
8 PIN R_ CH
NO NO
NO
Check IC200 (BU4052)
16PINVDD, 8PIN VSS power
YES
Replace the related part
Check the IC801
(MC4580) 4PIN VSS, 8PIN
VDD power
YES
Replace the related part
NO
Check the M-COM (IC301)
83PIN, 84PIN communication
Refer to SMPS
Troubleshooting.
OK
LGE Internal Use Only
YES
3-6
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
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8. TUNER FUNCTION PART CHECK
TUNER FUNCTION PART CHECK
YES
Check the TUNER module
(TU601) operation
YES
Check the input
waveform of IC200( BU4052) 1,12PIN
YES
Check the output
waveform of IC200 (BU4052)3, 13PIN
Check the input waveform of IC601
(BU4052)2, 15PIN
YES
Check the input waveform of IC801.
NO
NO
NO
Check the TUNER MODULE power
(check the 2PIN 9V)
Check the IC200 (BU4052)
16PINVDD, 8PIN VSS power
YES
Replace the related part
Check the IC801( MC4580)
4PIN VSS, 8PIN VDD power
OK
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3-7
YESYES
Replace the related part
LGE Internal Use Only
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9. TAPE FUNCTION PART CHECK
TAPE PCB ASS`Y
YES
Check the input waveform of
IC200(BU4052) 2, 15PIN
YES
Check the output waveform of IC200 (BU4052)3, 13PIN
Check the input waveform of IC601 (BU4052)2, 15PIN
YES
Check the input
waveform of IC801(MIC4580)2 ,6PIN
YES
Check the output waveform of the PN709
6 PIN L_ CH
8 PIN R_ CH
YES
NO
NO
Check the IC200 (BU4052)
16PINVDD, 8PIN VSS power
YES
Replace the related part
Check the IC200 (BU4052)
16PINVDD, 8PIN VSS power
YES
Replace the related part
LGE Internal Use Only
OK
3-8
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
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10. TAPE PLAY PART CHECK
TAPE PLAY PART
YES
Check the
IC201 (HA12237) 16
PIN 12V input
YES
Check the IC201: 5.26
PIN Signal Output
YES
NO
NO NO
Refer to SMPS
Troubleshooting.
Check the
A/ B DECK HEAD
YES
Check A DECK HEAD input
IC201 32, 39PIN
YES
NO
Check the related part
Replace HEAD WIRE and
Mecha
Replace the related part
Check the IC201
14 PIN MUTE
operation
YES
OK
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
NO
YES
OK
Check the IC202 10 PIN
HIGH operation
YES
Check the related part
YES
OK
3-9
NO
Replace the related part
LGE Internal Use Only
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11. TAPE REC PART CHECK
TAPE REC PART
YES
Check the
IC604 PS9829
#49, #52 PWM
output
YES
Check the IC201 7.24 PIN
REC input
YES
Check the IC201 10.21
PIN output
YES
NO
NO NO
Refer to SMPS
Troubleshooting.
Check IC100 23PIN HIGH
YES
OK
Replace the related part
Check the L203 2.3 PIN
oscillation
YES
. Check P2203 5.3 PIN input
. Check 8 PIN ERASE input
YES
OK
LGE Internal Use Only
NO NO
Check Q205(D1304)
BASE HIGH
YES
OK
3-10
Copyright © 2008 LG Electronics. Inc. All right reserved.
Check the IC202 4 PIN
HIGH operation
YES
Replace the related part
Only for training and service purposes
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12. MIC PART CHECK
MIC PART
YES
Apply JK302, JK303
and check. CN301
2PIN, 4PIN output
YES
Check the P312
2PIN. 4PIN input
YES
Check the IC304
(BA3308) 8 PIN input
YES
Check the
IC304 (BA3308) 3PIN
output
YES
Check the P306 15PIN output
(FRONT PCB Ass`y)
YES
Check the P7302 15PIN
input (MAIN PCB Ass`y)
YES
Check the input at both
terminals of R804,812
YES
Check the IC603
1, 2PIN input
NO
Check
IC304 6PIN 12V
YES
OK
NO
Check the power at
both terminals ofFB301
YES
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3-11
LGE Internal Use Only
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YES
IC603 → PS9830
communication check
9 PIN SOTO → 33PIN SDIN
10PIN LRCK → 32LRCK
11PIN MCLK → 30MCLK
13PIN BCK → 31BCK
YES
NO
IC100 38PIN →
IC603 Check the REST
operation
YES
Check each communication
line resistance
YES
NO
Check the IC603
input power.
YES
Check the
power at both terminals
of FB803
YES
NO
Replace the related
part
OK
Check the
PS9830 input
YES
OK
13. PWM MODULATION PART CHECK I
PWM MODULATION
PART CHECK I
YES
Check CN701
9PIN 5V
NO
NO
Troubleshooting.
Refer to PS9830
Troubleshooting
Refer to SMPS
OK
YES
Check IC505
input 5V and
output 3.3V
YES YES
LGE Internal Use Only
NO
IC505 input power
Check
5V
NO
Check CN701
9PIN 5V
3-12
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes