Date   : Mon, 22 Jul 2002 23:04:45 +0100
From   : "Julian Stenning" <julian_stenning@...>
Subject: Re: solidisk dfdc

Hi -

my dfdc is marked 'Issue 2 (c) 1985' and has  from left to right:
74LS174 74LS136 74LS157 x 3
above the 1770 and 8271.

It has one single wire connecting the 18th pin on the 1770 to the 1st pin of
IC86.

I'm sure I have the instructions somewhere, but I can't find them right now.

Regards,
Julian.

----- Original Message -----
From: "Andrew Benham" <adsb@...>
To: <bbc-micro@...>
Sent: Monday, July 22, 2002 9:52 PM
Subject: Re: [BBC-Micro] solidisk dfdc


> On Mon, 22 Jul 2002, W.Scholten wrote:
>
> > Does anyone have the installation instructions?
>
> No, but I've found some old hand-drawn circuit diagrams (reverse
> enginering!).
>
> > I want to know where the two leads go on IC86 & IC87 (it's a different
> > board to that on the 8bs website), and what to do if there's no 8271 DFS
> > fitted and what if there is (any connecting jumpers as for the standard
> > DDFS? Are the leads not needed if a full 8271 DFS is already installed?)
>
> The lead connected to pin 18 on the 1770 socket needs to go to
> IC86 pin 1.
> The lead connected to pin 19 on the 1770 socket needs to go to
> IC87 pin 5 or 9.
>
> From what I recall, the DFDC board assumed that one already had the
> 8271 disk upgrade fitted.
>
> My recollection of these boards is not 100% - the circuit diagrams
> I drew are dated 1988 and 1989, and I've not seen one of these
> boards since then.
>
>
> > And can one identify visually if solidsk DDFS & DFDC boards are the
> > later Acorn ADFS compatible versions? (i.e. able to use the Acorn ADFS
> > rom)
>
> DDFS
> ----
>
> The Mark 1 DDFS board has 1 x 74LS374.
>
> The Mark 2 DDFS board (which has the 1770 at the same addresses as the
> model B with 1770 DFS) has 1 x 74LS374 and 1 x 74LS136.
>
>
> DFDC
> ----
>
> The Mark 1 DFDC board has 3 x 74LS157 and 1 x 74LS374.
>
> The Mark 2 DFDC board (which has the 1770 at the same addresses as the
> model B with 1770 DFS) has 3 x 74LS157, 1 x 74LS374, and 1 x 74LS136.
>
>
> --
> Andrew Benham     adsb@...
> Southgate, London N14, United Kingdom
>
> The gates in my computer are AND OR and NOT, not "Bill".
>