I know it's been a LONG time since your post, but I just tried installing this on my A500 (Rev5 mobo). After going through a CIA chip (didn't quite have the pins lined up, and a pin then broke when trying to straighten it out - thank God I had a spare CIA), I couldn't get my A500 to boot up. I double-triple-etc. checked that the CPU and CIA were correct and seated properly, but when booting my monitor would remain blank, I could hear and see my hard-drive powering up and some sort of I-O, the red power light on my keyboard would light-up, and after about 10 seconds, the green floppy light on the keyboard would light up and then I would hear a loud HUM (almost like an alarm). I never could pin-point where the sound was coming from. I first tried disconnecting the floppy, then installing the CIA without the clockport CIA adapter - same thing. I finally removed the CPU clockport adapter and plugged it back in directly in the mobo and it booted without problems (phew).
I think I'll wait until I get my 3.1 ROM upgrade before trying again (and maybe order a couple more spare CIAs first).
