Would anyone know where I could purchase a programmed u212 gal 22v10b?
I can supply one - send me an Email if interested:
http://amiga.serveftp.netOut of interest, what's the fault you're seeing to reach the conclusion that U212 is bad? The device is mainly generating column/row address stobes for the chip memory DRAM. So if you're seeing valid clock and strobe inputs but seeing no column/row address stobes out (they should be there all the time regardless of what the A4000 is doing), then I'd agree it would be a U212 problem.
It's not that common for this part to develop problems. In 20 years of repairing A4000s, I don't recall ever seeing U212 needing replacement. That's not to say it can't fail of course.
Edit:
Just saw the photo (don't know why the A.org photo attachments only show as 'error' with IBrowse). Obviously lots of corrosion damage, and missing pads at U212. Did someone mistake a sledge hammer for a SMD rework station? :hammer:
Unless U212 has been visibly corroded, it probably won't have a problem. The missing pads can be fixed without too much trouble. And given that there's not much left of anything real time clock related, I'd suggest leaving it out completely. The system will run fine without U177/U178. You'll need U976 working to some extent, as the system software looks at the two lower bits read from this to determine you have the AGA chipset. Else you'll only get ECS screenmodes if you eventually get it booting. And check that MDAT from U975 pin 13 is connected to where ever it should on Lisa, else if the input at Lisa is floating then it won't generate certain clocks and the system won't boot at all.
