This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
This latest ZipGSx modification is pretty straightforward. When I decided I wanted a Cache HIT light instead of a Cache MISS light, I went to Rat Shack and bought a pack of Green LEDs (I like green. Blue or Orange will work just as well.) I tried adding an inverter to the circuit but it just didn't want to play (obviously a cache HIT is the opposite of a cache MISS, and the LED on the board lights up for cache MISSes). Through the experimenting, I found that I could get the LED to light as desired without any "extra" hardware except the LED itself. Simple mod: solder in the Anode of the LED to the Anode of the Cache Miss. Solder the Cathode to the Cathode of the Power LED. (Even easier way to say it: there are four solder points for the existing LEDs. We use the two in the middle. The long lead goes to the yellow side, the short to the red. position as is comfortable. I can only guess that this would be a nice thing to attach to the TURBO light on the front of a tower case, should anyone ever mount a IIgs/ZipGSX inside a tower case... (also, it might be nice to turn SW1-6 OFF and connect the pins to the TURBO button on front. I don't know how useful it would be, but it m ight come in handy one of these days...) By: David Empson