Re: UniDisk 3.5 problem

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

In article Jeff.Brielmaier@juge.com (Jeff Brielmaier) writes...

>sR>Jason Whorton <jason@microxl.com> wrote:
>sR>:Hello.  I bought a UniDisk 3.5 and am trying to use it with a IIc that
>sR>:reports "0" when I type in print peek (64447).  I get a "Device not Ready"
>sR>:error when I try to enter CAT, D2.  Does anyone have any idea of what might
>sR>:be causing that?
>sR>
>sR>Well since the first 3.5 is S5, D1 and you accessed D2, I figure the system
>sR>tried S6, D2 which is where it expects to find the second 5.25 drive.
> 
>Jason, if your //c reports a "0" then it does not support the UniDisk3.5.

    Incorrect. If you type "PRINT PEEK (64447)" from the Applesoft 
BASIC prompt and it reports a value of '0' or higher, then you have
the firmware revision that *does* support a UniDisk 3.5.

>You will need a motherboard swap (one that reports at least "1") in order
>to use the UniDisk3.5 on the //c.

    There is no such thing any IIc firmware that reports "1". Further-
more a motherboard swap is not required, you can do a ROM chip swap to
upgrade with a simple modification (cut one trace with a blade, close 
another with a drop of solder). Here are the possible values you can 
get, typing what I mention above--and what they are:

"255" = original ROM, only supports external 5.25 drive
  "0" = UniDisk 3.5 supported
  "3" = memory expansion motherboard
  "4" = memory expansion motherboard with ROM bug fixes
  "5" = Apple IIc Plus


Mitchell Spector
spec@vax2.concordia.ca