Date   : Tue, 25 Mar 2003 10:52:09 +0000
From   : James Fidell <james@...>
Subject: Re: BBC Micros, what else :)

Quoting Kate Kneebone (kate.kneebone@...):

>  They both claim to have issue 7 boards, but other than that, they're 
> quite different.  The one which is currently in the best cosmetic 
> condition has a power supply made in the UK and yellow printing on the 
> PCB, but no disc interface and looks like I remember Model Bs to look 
> from my schooldays (I had an electron and a Master 128 at home).  The 
> other one has a power supply made in Hong Kong, white printing on the 
> board and an 8271 disc interface with Watford Electronics' DFS, and all 
> the bits of disc interface other than the 8271 are soldered to the board 
> (scuppering my attempt to move it to the other machine!).  Intriguingly 
> this computer has a slightly different case from the other one, it's a 
> different texture and has what looks like a space for an extra sticker 
> on the bottom, on the other side from all the connectors to the normal 
> sticker.  Unfortunately it's got marker pen on the lid too. It's also 
> noisier than the other one, and hisses quite loudly when it's on.

I'm fairly sure that the older, slightly yellower, case is an early
machine with a later motherboard in it.  The less yellowed smother
surfaced case is something they brought in later on.  The older case
may also have a non switched-mode power supply, which is the less
desirable of the two.  I can't remember when the case design changed.
I have one of each, but both with issue 7 boards in, as I swapped one
myself years ago.

I'd guess the second machine came with the disk subsystem installed
and that's why it's soldered in.  Perhaps someone subsequently swapped
the Acorn DFS for the Watford one.

The hissing is, as far as I recall, fixable by adding a capacitor
somewhere, but I can't remember where.

I think I'd be inclined to swap the entire motherboard with the disk
interface into the better quality case and use that.

James