Sony a900/a850 BEEPER "problem"

I've got three of these and they all work great -- and I have the user manual.

The cameras all have an internal beeper that is supposed to sound when the subject is in focus or the self-timer is running. The default setting is ON. It can be turned OFF in the MENU system.

All of mine are set to ON.

However, I cannot get a beep out of any of them -- and NO, I don't need a hearing aid

It's hard for me to believe that I could end up with three cameras that have the same problem -- and otherwise work fine.

Any ideas?

I had to turn my A900 audio signal on, it does beep when in focus, did not try the self timer. Yeah what are the odds of three having the same problem.