What's the audible alarm in a BA11 for?

From: Daniel A. Seagraves <dseagrav_at_bsdserver.tek-star.net>
Date: Sat Nov 22 18:26:44 1997

On Sun, 23 Nov 1997, Tony Duell wrote:

> Eh??? What beep?? AFAIK no BA11 had a beeper fitted as standard.

Pretty.

>
> Firstly, BA11 covers a heck of a lot of PDP11 mounting boxes, from the
> tiny BA11-V (4 dual-height Q-bus slots in a case the size of a TU58 tape
> drive) up to at least a BA11-F (21" high rackmount thing with over 30
> slots, and a separate H742 PSU). What mounting box are you working with?
>

BA11-K.

> Secondly, some switch-mode PSUs will make audible noises if they're
> overloaded (shorted), or if they're unhappy for some other reason -
> basically the trasformer/inductor core vibrates at the switching
> frequnecy, and this may fall into the audible range. A few also do this
> if the load is too light - so if you run them with no load they may well
> do this. That sounds like what's happening here.

That's it. I can ignore that?
Received on Sat Nov 22 1997 - 18:26:44 GMT