Panasonic CTN 3176S No Sound

[Irv]

I have a Panasonic CTN 3176S (Chassis AEDP212) with no sound. Picture is
fine and all menu functions appear to work normally. However, I do
occasionally hear a short blurb from the speakers.

I tried flexing all of the boards to see if it was an intermittent
connection problem, but this did not pan out. Inspection for
questionable solder connections did not show anything. The speakers
themselves check okay.

Does anyone have any idea if this is a common problem in this chassis or
if it might be an expensive repair?

Thanks in advance for any input on this problem.

Irv