Apple IIGS: Don‘t Use DuoDisk on SmartPort



I am experiencing a problem using DuoDisk with the Apple IIGS.

Equipment
---------

"Blockbuster" Apple IIGS with Rev. 3.0 ROM, DuoDisk, Profile or SCSI HDA in
slot 7 (optional)

Reproducing the Problem
-----------------------

Plug the DuoDisk into the disk port on the Apple IIGS main logic board. Install
the ProFile in slot 7, and set the Control Panel to "your card." Leave both
DuoDisk drives empty and power on the system. Set startup to "Scan."

The DuoDisk LED for drive #1 should turn on, but the system will not start. Why
did the Apple IIGS skip the ProFile in slot 7? Now, power down the Apple IIGS
and put a non-write-protected disk in the DuoDisk drive. It still doesn't
start.

Power down the Apple IIGS and place a write-protected disk in the drive. Power
on the system. The system starts up as expected, following the "Control
Panel".

If the system appears to be "hung" following any of the above steps,
momentarily triggering the write-protect switch by inserting anything into the
drive allows the system to start up.

There appears to be a compatibility problem with the new Apple IIGS main logic
board and the DuoDisk. Performing the "DuoDisk/Apple IIGS fix" that is posted
on AppleLink has no effect since the problem appears to be hardware (firmware)
based.

I'm stumped. What's going on?

Tech Comm was able to reproduce this problem exactly as you describe.

There IS a compatibility problem with the DuoDisk and the Rev 3 Apple IIGS main
logic board.

A check with Engineering provided us with the only workaround. Do NOT use the
DuoDisk on the SmartPort. There is some code in the ROM that does not handle
the interface to a DuoDisk properly. As of February, 1990, the only workaround
is to use the DuoDisk on an interface card.


Published Date: Feb 18, 2012