Re: Problems with ZipGS Upgrade

[supertimer@aol.com (Supertimer)]

cptfa@aol.com (CPT FA) wrote:

>I followed the CSA2 FAQ on Accelerator Upgrades and tried mine.
>I had a 7Mhz ZipGS with a soldered oscillator (28Mhz Full size).
>I desoldered it and installed a 14 pin socket then replaced the
>28Mhz with a 50Mhz oscillator (Full Size).  When I reinstalled the
>card and powered up all I got was a black and white checker board
>screen.  When I removed the card and replaced the oriningal CPU
>chip I booted up just fine at 2.8Mhz :(.  Here's my questions; have I
>ruined my board?  Is there anything I can do to fix it?  Is there
>anyone out there that can do this upgrade/repair?  Thanks in
>advance for any assistance.

The checker board screen means your accelerator can't cope
with 12.5Mhz.  This may be due to the CPU or the accelerator
memory.  Did you replace the 7Mhz CPU with a new 14Mhz
65C816 unit?  This is needed for the speed you are trying to get
(12.5Mhz).

I suggest taking out the 50Mhz oscillator and replacing it with a
40Mhz oscillator and then trying to run your ZipGS as a 10Mhz
card.  Next, try a 36Mhz oscillator for 9Mhz.  Work your way
down until you get the fastest stable speed for your ZipGS/
computer combination.  I've also read that, for the ZipGS, if
you reach a speed where the accelerator works, but is not
stable, you can try reducing the cache size settings.  If you
have a 64k Zip, for example, you might try to change the dip
switch settings to read a 32k Zip.  Good luck!