Television - No sound on some channels

Model SJ2765S
11 Yrs old
System 3
MTS SEq Audio System

Television just experiencing sound problems. In particular audio problems differ from channel to channel

Get into the audio user menu and sit it back to stereo.
It is probably set to SAP at present.
Certainly that was one of the first tv sets to include the SAP audio program selection.

Beyond that the set needs properly troublshot and repaired by someone with the experience and more importantly the test equipment accordingly needed to diagnose the failure like that.

Look whether the channel which aren't presumably working are stereo. To illustrate if so, the problem might be cause by the infernal Sony sound module. That module is use in most if not all stereo TV sound decoder. When the channel is stereo, it must be decode by which module and when is fail, you will have the effect you describe. When channel are mono, the audio signal don't go by that module and the TV sound will work normally. Replace the module and you will be back in busines. The module is easy to locate, it's a small PCB (1" x 2" aprox)
with SMT parts and condensators on it, it is clearly mark SONY on it. We did replace many of those Sony sonnd module, all TV brand use that same module, not only Sony.

Thakns David