Date   : Thu, 28 Aug 2008 20:13:50 +0100
From   : jumbos.bazzar@... (Mark Haysman)
Subject: Question about 1770 DFS interface testing it on a B

Hi.

The Acorn 1770 DFS won't initialise if it doesn't see a 1770 board 
installed. Same with the ADFS, although that will fire up if it sees a hard 
drive, even if there's no floppy interface.

It won't appear on *HELP either, but it will be on a *ROMS list (if you have 
a rom or program to give you that function, now that the one in the 1770 is 
not initialised). Annoyingly, it will also kill SRAM if it sees no 1770 
chip.

If you can't dump the ROM, you could write a short program to pop the 
contents of the beginning of the ROM to the screen memory, to see if 
something resembling the ROM is still in there - that will at least give a 
clue if the ROM is totally dead or not.

Mark.

----- Original Message ----- 
From: "Andy Ford" <acorn@...>
To: <bbc-micro@...>
Sent: Thursday, August 28, 2008 6:51 PM
Subject: [BBC-Micro] Question about 1770 DFS interface testing it on a B


> Hi.
>
> I just wondered if anyone can confirm on a B, if the usual Acorn 1770
> DFS message should show up (on startup) or with *H. regardless of
> weather the actual module is fitted to IC78 or not assuming the rom is
> present.
>
> Reason for asking...  I have been going through my spares and faulty
> machines. I have removed a 1770 upgrade from a dead B, with the
> intention of fitting it to a working issue 7 (that already has an 8721
> DFS), as I do not have a B with 1770.
>
> I have tried swapping the various other parts for this upgrade around
> with other spares (so I think I can 99% rule out most of the common
> components), I have hopefully narrowed it down to either the rom or the
> actual module, and I do not have spares of these to test further. The
> module had four pins missing but I managed to carefully attach some
> small lengths of wire and a bit of a broken turned pin socket to make
> four "pins", I will do it properly if it is working.
>
> I have carefully followed the instructions regarding links etc so I am
> happy it is not a user error. I did fit one years ago for a friend...
>
>
>
> Thanks!
>
> Andy.
>
>
>
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