Date   : Mon, 14 May 2001 19:02:04 +0100
From   : Philip Peake <philipp@...>
Subject: Re: 1770 Disk Interface

I had a thought about having a go a while back. I couldn't find the 1770 or 1772
though (allthough there are still 8271s about, which surprised me). Actually,
come to think of it, I did find one company in the US, but they would only sell
them in bulk (30 of). The other bits and pieces were relatively easy to find,
though.

Phil



Mike Tomlinson wrote:

> In article <8F55B1918087D4118BCB00508B0CCEBB01921A3B@...>,
> Saddler, Chris <CSaddler@...> writes
>
> >Has anyone every tried to recreate a 1770 (or 1772) based disk interface
> >daughter board for the BBC Model B?
>
> I haven't, but have seen home brew ones.
>
> > i.e. make a PCB based on the schematic
> >shown at http://members.magnet.at/marku/bbc/hardware.htm
>
> Don't forget that in addition to the circuit, you will need two wire
> links, two 7438 buffer chips (74LS38 must not be used) and a DFS ROM.
> There may be other bits - I can't remember - though Mark's site also has
> the fitting instructions somewhere with a list of parts.
>
> I'd have thought the most difficult bit to find might be the 40 pin
> header to plug the assembly into the 8271 socket.  If you can't find
> this, have a look in the RS catalogue for 40 pin ribbon cable headers.
> Perhaps you could put the board on a short length of ribbon cable.
>
> Wouldn't it be easier to buy a second hand Beeb with one fitted and use
> that or salvage it?
>
> >I'd be interested in upgrade my 8271 based disk interface to the 1770. Also,
> >does the circuit remain the same for the WD1772 based interface?
>
> Yes.
>
> >If I get a positive response to this, my next question will be where to get
> >a WD1770/1772?
>
> CPC (www.cpc.co.uk) used to carry them some years ago.
>
> --
> "Security-wise, NT is a server with a 'Kick me' sign taped to it."
>                       - Peter Gutmann