Re: Q: Disk drives for //c...

[spec@vax2.concordia.ca (Mitchell Spector)]

In article pa.schaefer@fz-juelich.de writes...

>Mitchell Spector wrote:
> 
>>     Be aware the DuoDisk is not compatible with the ROM 3 Apple IIgs.
> 
>I remember there was something with two small capacitors on the DuoDisk
>analog board which have to be removed. Perhaps anybody else knows more
>about this?

    Yes, there were two separate modifications, yet neither one solves
the incompatibility between the ROM 3 motherboard and the DuoDisk 5.25.
The first modification was done to early DuoDisk drives, it prevented
the drive from accidentally destroying data on floppies during a warm
boot (OpenApple-Control-Reset) on all Apple II's. As for the second
modification, it was to enable the DuoDisk to daisy-chain to the back
of an Apple 3.5 or UniDisk 3.5 on an Apple IIgs. It normally draws too
much power to be daisy-chained off the GS's smartport (although alone,
plugged in by itself, it did not pose a problem).

    I've done the two modifications to both my DuoDisk 5.25 drives,
neither works on my ROM 3 system. I can't remember what the reason
was exactly, and whether it was hardware or firmware related, but it
just is not compatible.

Mitchell Spector
spec@vax2.concordia.ca