Date   : Wed, 23 Oct 2002 22:58:17 +0100
From   : "Richard Gellman" <r.gellman@...>
Subject: Re: BBC motherboard from a PC power supply

>I seem to recall a discussion about running a BBC B motherboard from a PC
AT power supply, but can't find any reference to it now.
>
>I have a spare Model B motherboard and keyboard and would like to know if
anyone has had any experience with fitting the motherboard into a PC case
and
>using a PC power supply to power it? Is there any info on the web about
this?

Its possible, but has to be done in a certain way.

IIRC, the BBC Micro requires 4 isolated supplies, 3 of +5v + 0v, and one
of -5v (this is a purple wire in my Model B).
The -5v line and at least one 5v/0v pair can be obtained from the main power
connector of the PSU. The other two you might have to gain from the drive
power connectors.

There's certain enough power in an AT PSU to drive a Model B at any rate.

Failing all that, you can always build an isolation grid with 1:1 isolator
transformers.....

-- Richard