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LC-37GE1E

7 – 1

LC-37GE1E

Service Manual

 

Power unit operation check.

Are the power cord and harness in the unit properly con-

nected ?

NO

Connect the power cord and harness properly, and turn on the power.

YES

Is F701 normal ?

NO

Are both ends of C704 and C715 short-circuited when checking their 

resistance values?

YES

NO

YES

Is a voltage of BU5V applied to pin (20) of  P701? 
(Set the main power SW to OFF.)

NO

Replace F701.

C704 ... Check VA701 , 
VA702 and D701.                          
C715 ... Check IC704 
and 705.

YES

Is it a symptom that the relay clatters twice as soon as the       
main power SW is set to ON and the power is not supplied? 

Is a voltage of approx. 8 - 15V 
to pin (4) of IC705?

NO

Check IC705, IC708, 
D725 and Q724.

NO

YES

YES

Does the same symptom 
appear even if R858 (2.7k) is
removed and the power is sup-
plied again ?

NO

Check short circuit of 5V line 
(D737, C752, etc.). 

YES

Check Q724, D731 , D734, 
IC707, D751 , D753, D754, 
D741 ,  D759 and D746.

Check IC704, D728, D762 and D736. If there are no problems, check 
the resistance value between pins (1) and (6) of P704.
When the value is low (several 

Ω- several hundred Ω),  disconnect 

P704. If the value is still low, the parts of 24V line are defective. When 
the resistance value is several 

Ω, check the inverter unit.

Does a relay noise sound? (Once) 

NO

Are PCON1 and 2 [pins (1) 
and (2) of  P702] at Hi (3V or 
more)?

NO

There is a possibility that 
control by P-CON is not 
performed
properly. Check whether 
the "PCON1" and 
"PCON2" signals 
are sent from pins (A23) 
and (A21) of  IC3002 (V-
PRO.) of  MAIN-UNIT.

YES

YES

Check peripheral circuits of D738, R828 and D735. 

Check peripheral circuits of 
Q712, Q713, Q721, Q723 
and RY701.

LC-37GE1E

7 – 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 IC303 or 
peripheral  circuits.

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

Has the audio signal cor-
rectly come to SP sub-
strate (D790WE/
D791WE)? 

NO

Check the connec-
tion of P301 and 
the SP substrate 
and harnesswire.

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

YES

Check soldering the ter-
minal
 and peripheral circuits.

YES

NO

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

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-37GE1E

7 – 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 (J1201) and 5 
(J1201) of EXT3 and connec-
tion 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), HEAD-
PHONE and  peripheral circuits. 

YES

 .

Check 

CONNECTOR(P301), 

SP_substrate(D790WJ/
D791WJ)  and 
SP-BOX(right and left). 

LC-37GE1E

7 – 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

OK

 

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), HEAD-
PHONE and  peripheral circuits. 

YES

 .

Check 

CONNECTOR(P301), 

SP_substrate(D790WJ/
D791WJ)  and 
SP-BOX(right and left).