2008-03-14 
LC-42SB45U 
 35 
 
No sound from external input devices (2) 
↓ 
Does not the sound of the audio signal input to INPUT 3(Composite, Y/C) go out? 
MAIN UNIT:      ↓ 
 
 
↓YES 
 
 
↓YES 
 
 
 
No sound from external input devices (3) 
↓ 
Does not the sound of the audio signal input to INPUT 7 (VGA) go out? 
MAIN UNIT:      ↓ 
 
 
↓YES 
 
 
↓YES 
 
 
 
No sound from external input devices (4) 
↓ 
Does not the sound of the audio signal input to INPUT 4/5/6 (HDMI1/2/3) go out? 
↓ 
 
 
↓YES 
 
 
 
 
The digital audio signal is not output (1) 
↓ 
No digital audio signal output from SPDIF_OUTPUT terminal. 
TEREMINAL UNIT:   ↓ 
 
 
↓NO 
 
 
 
 
 
 
 
Is the audio signal properly sent to pin (4) (AV3_AudioLIN) and pin 
(6) (AV3_AudioRIN) of CN650?
 
NO 
 
Check the connection to CN650 and the external input device.
Refer to “No sound output in all modes”. 
Is the audio signal properly sent to pin (K23) (AV3_LIN) and pin 
(K24) (AV3_RIN) of IC U400?
 
NO 
 
Check the line between CN650 and IC U400.
Is the audio signal properly sent to pin (2) (VGA_AudioLIN) and pin 
(3) (VGA_AudioRIN) of CN555?
 
NO 
 
Check the connection to CN555 and the external input device.
Refer to “No sound output in all modes”. 
Is the audio signal properly sent to pin (K25) (VGA_LIN) and pin 
(K26) (VGA_RIN) of IC U400?
 
NO 
 
Check the line between CN555 and IC U400.
Refer to “No sound output in all modes”. 
Is picture of the signal input from INPUT 4/5/6 displayed? 
NO 
 
Refer to “Does not the picture of the HDMI signal input to 
HDMI1/2/3 go out?”.
 
Check IC U400 and its peripheral circuits.
Is ASPDIF audio signal output from pin (B22) of IC U400 to pin (6) 
of connector CN553?
 
YES 
 
Check the connection to SPDIF_OUT and external devices.