Date   : Thu, 21 Jul 2005 22:43:05 +0100
From   : Mike Tomlinson <mike@...>
Subject: Re: floppy discs

In article <6.2.1.2.0.20050721085432.05270cf8@...>, Rob
<robert@...> writes

>reason I ask, I used to run a lot of beebs 24/7 (multi-user BBS, econeted 
>system - had about eight at one point.  Well, it was a lot for me!) and a 
>problem I came across several times was that one of the capacitors in the 
>PSU would fail, causing a longer and longer initial tone (of the two tones 
>the B usually makes) before powering on properly.

It's a very common fault, particularly as Beebs are now getting rather
elderly.  The capacitor is component number C9 in the PSU, next to the
switching transistor (the heat generated from which tends to speed up
the failure of C9.)

C9, if memory serves me, is a 220uF 35V electrolytic.  It's recommended
to replace it with a 105C low-ESR device.

M.