HA! Sometimes you have to get lucky... found that some LC VRAM SIMMs used the same 256Kx4 VRAM chips.
First two chips replaced:
Line is GONE.
Card is fixed.
Curious what happens when I put the two spare chips onto the LC SIMM
Should be the following:
-Apple II System Utilities
-Apple Presents the Apple IIc: An Interactive Owner's Guide
I have the original disks somewhere, so I can eventually double check that.
More complete list here: https://generalphiles.com/files/Apple/Apple II/Apple II Manuals/Apple IIc Welcome - Graphic Packing List.pdf
Thats what the original 1984 bundle came with. Later shipments likely differed.
Your Twinspark is still working fine, the Turbo040 however is shot.
I do get instant death chimes when turning on the IIci with it plugged in.
When measuring resistance to ground on the pin that got hit by 12V on the ASIC I get around 1k while on mine this is somewhere in the megaohms.
Even on some surrounding pins the resistance to ground is very low while on mine they are not. This indicates that something inside the chip shorted out.
Getting a replacement is going to be near impossible... some of those wonky chinese chip-trading-reseller-whatever sites say they stock a small amount of those.
@JDW care to send them an inquiry and see if they actually stock them? Chances are they are fakes, but that would be a weird part to fake as probably nobody ever is going to need one of those ever, except you
Part number for the chip is VY14676 and a google search will turn up two sellers.
Not sure if I am brave enough to swap in my ASIC just for testing
Did you make the cable? I would first start to make sure you don't have any cold solder joints, or bad solder joints. I just recently had this issue, where a wire broke off on the din side of my cable.