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

[shack@southwind.net (Randy Shackelford)]

In article <1dyz3s8.25kcvy4w89kwN@dempson.actrix.gen.nz>,
David Empson <dempson@actrix.gen.nz> wrote:
>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 had always heard that the card worked with the system running at 1 MHz.
Never had any inclination to test it naturally since Unidisks work on a
IIgs without the card.

>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.

That'd make sense if the card won't run in a IIgs at normal speed.

>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.

My //e has eight cards and it got to doing weird stuff which stopped after
putting in an AE P/S.
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