Hitachi L55S603 Service Manual page 14

3). No Sound, Sound Failed (Loading Interrupt, Noise, Etc.)
First, confirm the connection of all connectors between Board's and speakers, then survey by following the flowchart
as shown below.
No Sound, Sound failed
(Loading interruption,
Occured at only
Video1 input (CVBS), or
Video2 input (CVBS, S2)?
Voltage of
pin No.3 or 4 of CN701 on
Main Board is 12V?
Main Board or Speaker units
Noise, etc)
No
Yes
L55S603
Yes
No
14
Main Board
Power Board