Date   : Sat, 10 Sep 2005 07:14:35 +0100
From   : Sprow <info@...>
Subject: Re: BBC Micros used for Doctor Who

In article <6.2.1.2.0.20050910010916.04861330@...>,
   Rob <robert@...> wrote:
> At 22:34 09/09/2005, Richard Gellman wrote:

> >You may or may not be aware, but the BBC Micro was used quite
> >extensively for computer graphics during the 1980s on Doctor Who (The
> >Peter Davison, Colin Baker, and Sylvester McCoy eras).
>
> As far as Genlocks go, I saw one being demonstrated at a Micro User show 
> at 
> Manchester UMIST once..  I think that was the same show I bought my hard 
> disc at - £750 for 10Mb ...

At university, we had a "Beeblock" genlock unit for the BBC Micro. It had a
smallish (6x4") PCB chock full of resistors and tuning coils, then a DIN
lead which sneaked in through the Econet socket space which then ran flying
leads to various places on the PCB, mainly around the 6845 and 6502.

It used the external video to force the machine to stall and only continue
when it would result in locked video output. The result was that if you sent
the Beeblock dodgy video (or hopped lock sources) the beeb would crash in
some unpredictable way with "Bad program".

Otherwise it worked very well and allowed its output to be mixed with live
video using an external vision mixer,
Sprow.