Date   : Wed, 20 Dec 2006 09:03:34 -0000 (GMT)
From   : splodge@... (Richard Gellman)
Subject: Curse of the long TUBE cable

Hi,

I recently unearthed an old 6502 cheese wedge in the cupboard, and fished
it out with a view to setting up alongside the model B. It had been in the
cupboard as I had to kidnap its TUBE OS ROM for use on my 65C102 internal
co-processor in my Master 128, who's ROM had suffered mysteriously in the
hands of a previous owner..

Having recently managed to resurrect the thing by use of a newly
programmed ROM to replace the original (with thanks to Ian Wolstenholme
for the 2732A EPROM supply :) ) a quick test confirms it still works.
Excellent.

I then got this rather silly idea to replace the unpleasantly short TUBE
cable with something a bit more feasible. This is necessary as the
situation of my model B does not afford an alongside placement.

So, one quick cable change later and... nothing. No fault or anything, it
just doesn't "activate". I still get the standard issue "BBC Computer
32K". Its as if the cheese wedge wasn't even plugged in.

Now, I'd been warned in advance that this might not work, but I thought
I'd hazzard a try...

I'm told that strategically placed line drivers on the TUBE lines might
resolve the problem, but this is not a guarantee. I'd be interested in
people's thoughts on getting it up and running. As far as I can tell the
cheese wedge board has suffered no ill fates.

As mentioned, using a shorter lead is physically impossible due to space
restrictions (the wedge needs to sit off to the side somewhat). I don't
want to wire the board in internally as I'd like the option to switch the
board off as required. This could be done by hacking a switch onto the
TUBE NCS line, but I'd prefer a more elegant solution.

Any thoughts?

Cheers

-- Richard