Re: How many 5.25 inch floppies with the IIc support

[dempson@actrix.gen.nz (David Empson)]

Mike <mike@bogus.address.net> wrote:

> David Empson wrote:
> 
> > You can update the firmware to the version which supports the UniDisk
> > 3.5.  Your other IIc has the right firmware (FBBF = 00), so you can copy
> > the ROM from this machine.
> > 
> > You need a 27C256 EPROM (32Kx8).  Installing it in the older IIc
> > requires two minor modifications to the motherboard: a track cut and a
> > solder blob.  Both are near the ROM, and are clearly marked.
> 
> Actually, an A2S4000 IIc may not have the electronics for controlling the
> Unidisk.  There is a page here that describes the modifications necessary:
> 
> http://www.apple2.org.za/gswv/USA2WUG/FOUNDING.MEMBERS/HOME.PAGES/HANK/
> hl.A2c.article1.html

Interesting.  I wasn't aware that Apple left any components off the
early IIc models.

I successfully upgraded my user group's IIc (donated by Steve Wozniak)
using the method I described.

> I think that it's a bit had to perform if you need to install the 
> resistors, LM311 and NE555.

A bit "hard" perhaps? :-)

Yes, that would involve more work, including removing the logic board.

-- 
David Empson
dempson@actrix.gen.nz