Steven Hirsch wrote:
sfahey wrote:To: limtc Re: Fastest Apple IIGS accelerator? By: limtc to comp.sys.apple2 on Fri Sep 21 2007 01:25 am > What's the fastest Apple IIGS accelerator out there? > > I remember: 14MHz Transwarp GS and 12MHz Zip GS? Right? I have seen a stable 20MHz TWGS, that required active cooling.I am now the proud owner of both a Zip GSX and AE Transwarp GS. I'd like to take the plunge and modify one of these for higher speed operation. From others' experiences, which is the better bet? What speed should I shoot for? How big should I make the cache?Steve
I recently upgraded my Zip GSX to 12.5Mhz at which it runs stably. I tried for 16Mhz (a bit optimistic) but the machine wouldn't get past POST. To get these higher speeds, further modifications to a Zip GSX are required - you need to replace the two 74Fxx logic chips with the faster equivalents (74ACTQxx). This modification is for the *real* adventurous, as it involves de-soldering the two logic chips. At this stage, I am happy enough with 12.5Mhz (I might be able to push it further, but I need higher speed crystals). GSE-Reactive sell the logic chip upgrade (as well as everything else you need), but I think that these are fairly easy to obtain from many electronic suppliers. I opted to buy my components elsewhere as I found suppliers that were either local, or cheaper.
I took photo's of what I did to modify my Zip GSX, and I will be posting the details onto my web site soon. The modifications I performed were largely based upon an old hypercard stack that I found that outlined the procedure.
I will post back when I have put up the photo's and steps required to mod a Zip GSX if anyone is interested.
cheers, -p