Date   : Fri, 12 Sep 2003 08:01:23 +0100 (BST)
From   : Peter Turnbull <pete@...>
Subject: Re: BBC-B video processor

On Sep 12, 14:05, Bob Devries wrote:
> What is the part number of the video processor in the BBC-B?
>
> The one in mine syas VC2069. I thought that was the one from the
master?

The Model B used different chips at different times during production,
all of which were (more or less) interchangable.  The original was the
Ferranti ULA which needs the black heatsink.  This was replaced by the
first version of the video processor, which doesn't need a heatsink.
 However, one of the control inputs was slightly different on the first
version, and the jumper links at S26 had to be removed and a wire
fitted from the centre pin of the 3-way link to a signal on the
underside of the PCB.  The later versions didn't need this, and S26 was
restored to normal function.

The Master used the same video processor as the later Beebs.

-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York