Date   : Thu, 16 Apr 2009 18:59:52 +0100
From   : cris@... (Crispin Boylan)
Subject: Disc Fault FD

Crispin Boylan wrote:
> Hi All,
>
> I'm getting a weird error message when trying to use my floppy drive 
> on my trusty Model B.  When I enter any disc commands I get "Disc 
> Fault FD at FD/00" instantly returned (no attempt visible attempt to 
> access the drive or wait for a response).  Having searched through the 
> Acorn DFS manuals and online I cant see that this code even exists!  
> FC and FE seem to, but not FD!  Even a scan of the 8271 datasheet I 
> can't see how this result code would be formed.
> I did get the drives working briefly but now cannot at all.  Both 
> drives are the same.  In fact the error doesn't change even without 
> drives connected!
>
> Anyone got any ideas?
>
> thanks
> cris.
>
just for the record - this was eventually traced to a faulty 8271!  
Popped in a spare one and the problem was gone.  Never heard of one 
failing before, but my PSU was running quite high (~6v on the 5v line) 
before I replaced most of the electrolitics, so that could have done it 
I guess.

cris.