Óscar Toledo G.5d ago
I've repaired a TI-99/4A. The video chip was failing, and it was replaced. But the screen was still black, I followed the trail to the CPU that didn't generate any address at all (tri-state). I got a TMS9900 from China, removed the original, put a socket made of pin rows, and et voila! #retro #retrogaming #ti994a
Show threadTursilion

@nanochess CPU going is definitely a more rare failure for the old TI, but we are reaching the point where any chip on the board is an option.

I'm impressed you sourced a working one from China though. I wonder what they are pulling them from... :)

Mar 21 at 10:06pmWeb
Show threadÓscar Toledo G.4d ago
@tursilion I'm surprised it was the processor. Maybe a power spike or the VDP damage carried along to the processor. The Chinese guy probably bought oxidized old-stock. It looks like the pins have been polished manually because some pins are slightly lower.