Re: Trouble with Apple //e & Unidisk 3.5 & 4mhz. ZIP chip

[dempson@actrix.gen.nz (David Empson)]

Ed Hillman <ehillman@erinet.com> wrote:

> Any ideas out there?

My initial thought was some kind of DMA compatibility issue, as
mentioned by SuperTimer.  The UniDisk card itself doesn't use DMA.

The only major thought that I have to add is that there is known to be
something slightly odd about the UniDisk 3.5 card ("Liron").  For
example, it does not work in a IIgs.

I think this is due to a bus timing issue, but I'd have to do rather a
lot of searching through old information to locate anything useful on
the subject.

If it is a timing issue, the Zip chip could be causing a similar
problem.


Another comment: you have an awful lot of cards in there.  Do you have a
heavy duty power supply?  You might be running into a loading problem on
one of the power rails.  Try pulling every card except the Duodisk and
UniDisk 3.5, and put the ZIP back in.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P O Box 27-103, Wellington, New Zealand