LC-42XD1E (serv.man5). Troubleshooting Table - Sharp TV Service Manual (repair manual). Page 5

     LC-42XD1E/RU

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No audio output from the 
headphones.

No audio output from 
EXT1 (SCART) terminal.

                  

              

Is there audio output on 
pins (2) and (3) of the 
headphone terminal 
(J1301)?

Checklist:
1) Is the MUTE button on the remote control set to ON? ... Set to OFF.
2) Check the connection to external devices .... Is there any improper connection?

NO

              

Is audio input/output sig-
nal of pins (3) and (5)/(1) 
and (7) of IC303 (OP-
AMP) normal?

Is audio signal sent to pins 
(3) and (1) of EXT1 
(J1101)? 

NO

Is S-MUTE-LINE [IC1710 
(pin 92)] at H? 
(Check Q1106/Q1105 
operation.) 

NO

YES

            

NO

Is audio output signal 
(SPK- OUT L/R) properly 
sent from pins (28) and 
(27) of IC3701 (MSP)? 

Check the connection to 
EXT1 (J1101) and exter-
nal devices.

Is audio signal sent from 
pins (33) and (34) of 
IC3701?

NO

Check the power supply 8/
5 V pins (39) and (12) of 
IC3701 and peripheral cir-
cuits.

NO

YES

Check audio input signal 
of pin (67) of IC3701 
(MSP), pins (39) and (12) 
of the power line5 and 8V, 
pins (3) and (2) of I2C-
LINE, and peripheral cir-
cuits. 

Check the audio signal 
output line from pins (33) 
and (34) of IC3701 to pins 
(3) and (1) of EXT1.

              

             

No audio output from 
EXT2 (SCART) terminal.

No audio output from 
AUDIO OUTPUT terminal.

              

             

Checklist:
1) Is the MUTE button on the remote control set to ON? ... Set to OFF.
2) Check the connection to external devices .... Is there any improper connection?

              

             

Is audio signal sent to pins 
(24) and (22) of EXT2 
(J1101)?

NO

Is S-MUTE-LINE [IC1710 
(pin 92)] or S2-MUTE-
LINE [IC1710 (pin 90)] at 
H? 
 (Check Q1102/Q1101 
operation.)

Is S-MUTE-LINE [IC1710 
(pin 92)] at H? 
(Check 1204/Q1203 oper-
ation.) 

NO

Is audio signal sent to pins   
(13) and (15) 
[L/R (white) (red)] of 
AUDIO OUTPUT 
terminal (J1201)?

YES

NO

              

NO

YES

Check the connection to 
EXT2 (J1101) and exter-
nal devices. 

Is audio signal sent from pins (36) and (37) of IC3701?

Check the connection to 
AUDIO OUTPUT terminal 
(J1201) and external 
devices. 

NO

YES

Check the power supply 8/
5 V pins (39) and (12) of 
IC3701 and peripheral cir-
cuits.

Check the audio signal 
output line from pins (36) 
and (37) of IC3701 to 
Q1103/Q1104/Q1201/
Q1202.