Re: Zip GSX

[Rubywand <rubywand@swbell.net>]

CPT FA writes ...
> 
> Can anyone in th Apple II community refer me to someone who can repair and
> upgrade a Zip GSX?  I tried the upgrade myself and only succeded in
> rendering my card, 7Mhz 32K Cache,  inoperative (black and white
> checkerboard screen).  I would greatly appreciate any suggestions.
 ....

     First, finding someone to repair a ZipGS accelerator is not likely to be
easy. Schematics and detailed docs have never been released; and, there does
not seem to be a source for replacement of proprietary parts. So, anyone who
offers to do repairs is taking a big chance of failing.

     As Supertimer notes, information about what you did when attempting the
upgrade would help. For instance, what speed are you trying for? If you go from
7MHz to 10MHz, the upgrade is likely to be simpler and your chances of success
are better than if you attempt to go to 15MHz.  (Mainly, for 10MHz, you would
swap in the new 16MHz 65C816 and a 40Mhz oscillator module. You might not need
to mess with the RAM at all.)

     It could, also, help to know what other cards are installed in your GS.


     One possibility is that there is nothing wrong with your upgrade. The
ZipGS boards I've seen have contact traces which do not extend all the way to
the bottom of the card. This can lead to poor connections with Slot contacts
when the card is pulled and reinserted; and, you get the checkerboard screen
you mention.

     Try cleaning the card contact traces and Slot contacts with an alcohol
swab. When you insert the card, make sure to press it all the way down into the
Slot-- the Slot contacts touch the card traces pretty close to the bottom edge
of the card.




Rubywand