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LC-42XD10E/RU

4 – 1

LC42XD10E

Service Manual

 

Are the power cable and harness in the unit properly connected?

NO

Reconnect the power cable and harness properly, and turn 
on the power.

YES

Is F701 normal?

NO

Is the fuse still blown when turning on the power after replac-
ing F701?

YES

No

YES

Is approx. 5V applied to the BU5V output [between pins 20 (+) and 
22 (-) of PA]?

Is a voltage of 8V or more generated at C790?

YES

NO

NO

YES

Replace R790, D742, 
IC702, R780, and R781.

Replace R790, D742, 
IC702, R780, and R781.

Replace Q705, D715, 
IC701, R726, and 
R721.

Are approx. 13V, approx. 24V and approx. 35V generated at the 
UR13V, S29V and UR35V outputs respectively?

NO

Check D708, Q727, Q726, R830, R829, D762, D763, Q741, 
R824, R825, IC704, R826, R827, and R828.

YES

Is a click heard when the replay is turned on?

NO

Check Q706, Q741, D707, R729, and R776.

YES

Is approx. 12V generated at UR12V [between pins 1 (+) and 3 (-) of 
PL]?

NO

Check Q731, Q742, Q732, D767, D766, R843, R844 and 
C799.

YES

Is a voltage of approx. 380V generated at C726?

NO

Check Q705, D715, IC701, R726, and R721.

YES

Is approx. 60V generated at the INV60V output [between pins 1 (+) 
and 3 (-) of LA]?

NO

Check Z1, Q707, Q708, Q716 and L706.

YES

Is approx. 10V generated at the INV10V output [between pins 5 (+) 
and 3 (-) of LA]?

NO

Check IC705, R832, R833, R834, and C813.

LC-42XD10E/RU

4 – 2

 No sound (1) (during the reception of TV broadcasting) 

No audio output during UHF/VHF reception

Checklist:
1)  Is the volume set to MIN or MUTE on the remote control ? ... Set the desired volume.
2)  Are headphones connected to HEADPHONE (J1301 ) ? ... Disconnect them.  
3)  Is ANT-CABLE disconnected or connected improperly ? ... Connect it correctly as per the operation manual.  

Is the audio signal (L/R) 
sent from pins (28) and 
(27) of IC3701 (MSP)? 

NO

Is the SIF signal 
(ANA_IN1+) sent to pin 
(67) of  IC3701(MSP)?

YES

Check whether +5V and 
+8V are supplied to pins 
(12) and (39) of IC3701 
respectively. Or,check 
peripheral circuits.

(AV-UNIT)

YES

NO

Is the audio signal of pins 
(3)  and (5) of IC303 (OP-
AMP) sent properly?  

NO

Check SC2704 
and P1201 or 
peripheral  circuits.
Is the S-MUTE sig-
nal “L” ?

Is the audio signal (SIF) 
sent from pin (1) of CON-
NECTOR (SC2705)?

YES

Check pin (67) of  IC3701 
(MSP) and peripheral cir-
cuits.

YES

(TUNER)

NO

Is the audio signal of pin 
(4) of IC301/IC302 
(AUDIO-AMP) sent prop-
erly?

NO

Check HEAD-
PHONE 
(J1301) or periph-
eral circuits. 

Is the audio signal (SIF) 
sent from Q210 (Buffer)? 

YES

Check CONNEC-
TOR(P201) and periph-
eral circuits.

YES

NO

Is the audio signal output 
of  pins (2) and (4) of P301 
(AUDIO-CONNECTOR) 
normal ? 

NO

Check P301 
(AUDIO- CON-
NECTOR) and 
peripheral circuits. 

Is the SIF signal sent to 
Q203 (AMP)?

YES

Confirm whether +8V is 
supplied to Q203. Or, 
please check the periph-
eral circuit.

YES

NO

Check SP-BOX (right and 
left) and wire harness. 

Is the SIF signal sent from 
pin (13) of  TUNER 
(TU201)?

YES

Check soldering the ter-
minal
 and peripheral circuits.

NO

  

Check whether 5V (ANT ) 
and 5V are supplied to 
pins (4) and (10) of  
TUNER (TU201) respec-
tively. Check SDA/SCL 
and AGC signal.

YES

Replace TUNER 
(TU201).

LC-42XD10E/RU

4 – 3

 No sound from external input devices (2) -1 

No sound from an external input 
device connected to EXT1 
(SCART1).  

No sound from an external   
input device connected to 
EXT2 (SCART2). 

No sound from an external input 
device connected to EXT3. 

<EXT1>
Is IN1-L audio signal sent from 
pin (6) of SCART1 terminal 
(J1101) to pin (53) of IC3701 
(MSP)?
Is IN1-R audio signal sent from 
pin (2) of SCART1 terminal 
(J1101) to pin (54) of IC3701 
(MSP)?

YES

<EXT2>
Is IN2-L audio signal sent 
from pin (27) of SCART2 ter-
minal (J1101) to pin (56) of 
IC3701 (MSP)?
Is IN2-R audio signal sent 
from pin (23) of SCART2 ter-
minal (J1101) to pin (57) of 
IC3701 (MSP)?

YES

<EXT3>
Is IN3-L audio signal sent from 
pin (3) of
J1201 terminal to pin (47) of 
IC3701? 
Is IN3-R audio signal sent from 
pin (5) of  J1201 terminal to pin 
(48) of IC3701?  

NO

NO

NO

Check pins (6) and (2) of 
SCART1 and connection to an 
external input device. 

Check pins (27) and (23) of 
SCART2 and connection to 
an external input device.

Check pins 3 and 5 of EXT3 
(J1201) and connection to an 
external input device. 

  

Is the audio signal properly sent from pins (28) and (27) of IC3701 ?

NO

YES

Check IC3701 or peripheral circuits. 

 

Is the audio signal of  pins (1) 
and (7) of IC303  (OP-AMP) 
sent properly?  

NO

Check IC303 or peripheral circuits.   

YES

 

Is the audio output  signal of 
pins (13) and  (16) of IC302/
IC301(MAIN-AMP) normal?

NO

Check IC302/IC301 (MAIN-AMP), 
HEADPHONE and  peripheral circuits. 

YES

 Check 

CONNECTOR(P301) 

and  SP-BOX(right and left). 

LC-42XD10E/RU

4 – 4

 No sound from external input devices (2) -2 

No sound from EXT4 (AUDIO) 
connecting an external input 
device.  

No sound from EXT5 
(AUDIO) connecting an exter-
nal input device.

 

<EXT4>
Is D-SUB-L audio signal sent 
from J2702 to pin (15) of 
IC2704? 
Is D-SUB-R audio signal sent 
from J2702 to pin (2) of IC2704?

<EXT5>
Is HDMI-L audio signal sent 
from J2701 to pin (14) of 
IC2704? 
Is HDMI-R audio signal sent 
from J2701 to pin (5) of 
IC2704?

  

YES

YES

Is D-SUB-L audio signal sent to 
pin (50) of IC3701? 
Is D-SUB-R audio signal sent to 
pin (51) of  IC3701?  

Is HDMI-L audio signal sent 
to pin (50) of IC3701? 
Is HDMI-R audio signal sent 
to pin (51)  of IC3701?

NO

Check output of pins (13) and (3) of 
IC2704 and  peripheral circuits.
 

YES

YES

Is the audio signal properly sent from pins  (28) and (27) of IC3701 ?

NO

Check IC3701 or peripheral circuits. 

YES

 

Is the audio signal of  pins (1) 
and (7) of IC303  (OP-AMP) 
sent properly?  

NO

Check IC303 or peripheral circuits.   

YES

 

Is the audio output  signal of 
pins (13) and  (16) of IC302/
IC301(MAIN-AMP) normal?

NO

Check IC302/IC301 (MAIN-AMP), 
HEADPHONE and  peripheral circuits. 

YES

 Check 

CONNECTOR(P301) 

and SP-BOX(right and left).