User`s guide

oscillator), which will make a 12.5MHz Zip. The oscillators are cheap enough to
get two or three for experimenting with higher speeds.
So, you just plug your Tag and Data RAM chips into the Digi-Key adapters
and plug the adapters into the Tag and Data sockets of the Zip. Then, you
install the new 65C816 and oscillator and make sure DIP switch 1-7 and 1-8 are
both set OFF (for 64k cache). That's it, done completely without soldering.
ZipGS boards vary. On some you may be able to go above 12.5MHz by just
plugging in a faster oscillator. On others, you may have to choose between
getting faster Data RAM or settling for a lower speed. The new 65C816 is rated
for 16MHz and many users have gone to 14MHz and above. For speeds above 12.5MHz,
the usual recommendation is to get Data RAM rated at 35ns or better.
For a step-by-step guide, download my ZipUpgrade.SHK HyperCard stack at
http://www.apple2.org.za/mirrors/ground.icaen.uiowa.edu/apple16/ in the
Hypermedia/Hypercard/ folder.
______________________________
From: Wayne Stewart
I've sped up several ZipGS's and always topped out at 12 or 12.5MHz until I
replaced the 74F00 on the board with a 74HC00. I'd strongly suggest taking the
ZipGS as far as you can with plug-in parts, which'll likely be to about 12MHz;
then, give the 74HC00 swap-in some thought.
______________________________
From: Scott G. and Andrew Roughan
020- Do I need new GALs to speed up my TransWarpGS?
Probably not. The new 14MHz 65C816's available from WDC make it generally
unnecessary to swap in new GAL chips to go to higher speeds. In fact, one user
with the faster GALs already installed reports that his TransWarpGS would not
work until GAL 3E was replaced with an older GAL 3A.
If you are attempting to use an older 65C816-- e.g. a 10MHz chip released
in the early 1990's-- then, it may be necessary to upgrade the GALs (especially
GAL 3A) to run reliably above 10MHz. Due to variations in boards and parts,
about the only way to find out is to experiment.
______________________________
From: Henry S. Courbis
A source for upgrade GALs is GSE-Reactive at http://www.gse-reactive.com/.
______________________________
From: Rubywand
021- I have an 8kB TransWarpGS. How does a cache upgrade
compare with a speed upgrade?