Hitachi 42HDF52A Service Manual page 21

No optical audio sound
No audio service
Is the multi I/O connector
connected with scaler board
Yes
Is it in "MUTE" mode
No
Be sure this channel
was been locked
Yes
Change the tuner module
No
No
Yes
No
No
Scan this channel by
using "Manual Scan"
No
21
Connect it firmly
Is the audio work
Press "MUTE" or "VOL+"
so that audio work
Is the audio work
Yes
Problem has
been resolved
Yes
Problem has
been resolved
Yes
Problem has
been resolved