PC6300 Floppy controler

[Peter Fales]

In article <4176 at blake.acs.washington.edu>, dlarsen at blake.acs.washington.edu (David Larsen) writes:
> I have an ATT PC6300 with a dead floppy controler. I have been trying to 
> work around this using another floppy controler with no sucess.  I seem
> to remember that someone posted a file on how to use other controlers
> in these computers. If someone with that document or someone that might 
> know a work around I would be greatful for advice.

I am operating somewhat from memory here, but I am pretty sure this
is correct:

When the 6300 accesses peripherals that it thinks are on the system board
(like the floppy controller), the signals are not sent to the expansion
bus.   There is a PAL which determines what address ranges are mapped
to the system board.  This is a 20 pin device in a socket next to the
two EPROMs on the system board.  Lifting pin 17 will disable the 
system board controller and allow access to an external floppy 
controller.  Be careful not to break the pin - the PAL is difficult
or impossible to replace.

-- 
Peter Fales			AT&T, Room 5B-420
				2000 N. Naperville Rd.
UUCP:	...att!peter.fales	Naperville, IL 60566
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