LC-37XD1E (serv.man4). Troubleshooting Table - Sharp TV Service Manual (repair manual)

lc-37xd1e (serv.man4) service manual
Model
LC-37XD1E (serv.man4)
Pages
23
Size
1.2 MB
Type
PDF
Document
Service Manual
Brand
Device
TV / LCD / Troubleshooting Table
File
lc-37xd1e-sm4.pdf
Date

Read Sharp LC-37XD1E (serv.man4) Service Manual online

LC-37XD1E/RU
4 – 1
LC-37XD1E
Service Manual
 
CHAPTER 4. 
TROUBLESHOOTING TABLE
[1] TROBLESHOOTING TABLE
Power unit operation check.
Are the power cord and har-
ness 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-cir-
cuited when checking 
their resistance values?
NO
Replace F701.
YES
YES
C704 
⋅⋅⋅ Check VA701 , 
VA702 and D701.                          
C715 
⋅⋅⋅ Check IC704 
and 705.
Is a voltage of BU5V applied 
to pin (20) of  P701?
(Set the main power SW to 
OFF.)
NO
Is a voltage of approx. 8 
- 15V to pin (4) of 
IC705?
NO
Check IC705, 
IC708, D725 and 
Q724.
YES
YES
Check short circuit of 5V 
line (D737, C752, etc.).
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 sup-
plied?
NO
Does a relay noise 
sound? (Once) 
NO
Are PCON1 and 2 
[pins (1) and (2) 
of  P702] at Hi 
(3V or more)?
YES
YES
YES
Check peripheral cir-
cuits of D738, R828 and 
D735.
Check peripheral 
circuits of Q712, 
Q713, Q721, 
Q723 and RY701. 
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.
Does the same symptom 
appear even if R858 (2.7k) is
removed and the power is 
supplied again ?
NO
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 k
Ω check the 
inverter unit.
YES
Check Q724, D731 , D734, 
IC707, D751 , D753, D754, 
D741 ,  D759 and D746.
     LC-37XD1E/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-37XD1E/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), HEAD-
PHONE and  peripheral circuits. 
YES
 .
Check 
CONNECTOR(P301) 
and  SP-BOX(right and left). 
     LC-37XD1E/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), HEAD-
PHONE and  peripheral circuits. 
YES
 .
Check 
CONNECTOR(P301) 
and SP-BOX(right and left). 
Page of 23
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