Date   : Tue, 25 Mar 2003 13:02:37 +0000
From   : "W.Scholten" <wouter.scholten@...>
Subject: Re: BBC Micros, what else :)

Kate Kneebone wrote:

>  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!).

Common for BBC's that were delivered from the fatory with disc
interface.

>  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.

See my web pages for an analysis of this machine. There is some texture
difference between the Honk Kong and new-case machines, but not much. If
the one case feels rough (and has a round ADC port coutout among other
things), then the PCB must been replaced in this machine (those cases
were used up to issue 4).

Permanent marker pen (no it itsn't!) writing can usually be removed with
spritus (not sure if this is the name used in english, but it's the
alcohol variant with blue dye added, alcohol probably works too but
that's more expensive to try :) ).

Wrt noise, yes, I noticed this too. Being issue 7, it should have the
modification for noise reduction, but I haven't checked on my machine.
It's sufficiently noisy for me to not use this machine! You may try the
modification (try with 20k or so in case it has the 10k resistor
already, maybe 5k won't hurt but.... Or check to see if it really has
the 10k resistor). See e.g.

http://www.howell1964.freeserve.co.uk/Acorn/BBCmicro/guide/bbc_hw_06.htm


> At the moment, I've got the lid of the UK computer on the bottom half of
> the Hong Kong one.  This doesn't quite work as they're both different
> textures and the UK lid isn't yellowed but the Hong Kong base is!  I
> have a feeling that the UK machine is the better one.  I'm intending to
> order it a shiny new 1770 disc interface from the nice blokey at 8-bit
> software. However, I'd be interested in what expert BBC people think
> about the merits of the two machines.  Oh and any upgrades you think a
> really good Model B should have and where I can get them from would be
> interesting too; I handle all sorts of electronics at work, so hopefully
> a BBC micro shouldn't be *too* tricky to upgrade :)

a ROM board with at least 16K sideway ram.

> (never thought I'd have a BBC lid in my washing up...)

Won't remove the yellowing, or oranging for that matter ;)

Regards,

Wouter
-- 
BBC/atom/old magazine scans etc:
http://www.astro.livjm.ac.uk/~bbc/