Date   : Sun, 08 May 2005 13:09:25 +0100
From   : "BeebMaster" <beebmaster@...>
Subject: Re: BBC MASTER - UNUSUAL MOS ROM

I used to have a BBC Master like this.  I think I sold it on E-Bay a couple
of years ago so it
might be the same one!

I suspect it is a very early one.  Is it an Issue 1 PCB?

Best wishes,


Ian

----- Original Message -----
From: Mike Howard
To: 
Cc:   bbc-micro@...
Sent: Sat, 07 May 2005 17:18:09 +0100
Subject: [BBC-Micro] BBC MASTER - UNUSUAL MOS ROM

Hi All,

I have just acquired a BBC Master via ebay. On the face of it it is 
normal but lifting the lid exposes an unusual MOS ROM. The ROM itself is 
MOS 3.2 with the following markings;

551   VM   9481
231024-1028
0201,843-0
@...
SING-T

What is strange is that it is mounted on top of a miniature pcb (of 
Acorn origin) with a DM74LS04N chip under slung the pcb. The pcb is then 
mounted on top of a 28 pin IC socket which plugs into IC24 on the 
motherboard. Anybody any ideas as to what this configuration is for? 
Neither *help nor *roms reveal any clues. I've seen many Masters but 
never with a ROM like this.

The are eight images at http://howard.homeunix.com/pub/images/

Regards,
Mike.
-- 
Mike Howard                    aixguru at blueyonder dot co dot uk
Eccleston
UK