Atari 65xe and 800xl black screen

[apolkosnik]

I wanted to share my journey through black screen issue.

The 800xl was working, and I was using it for part-swap testing with 65xe.

The 65xe had black screen, making a pop sound when turned on, also it ran Star Raiders.

I think I was getting dark-green screen when powered up holding RESET button.

I've started by installing sockets, one by one, and initially I though that Freddie was fried... it had black pins, but swapping it with a new one didn't do much.

I've replaced the memory, replaced the mmu chip, GTIA, OS chip, still no go.

I've acquired CPS SuperSALT cartridge, and 65xe actually blinked very quickly:

SYSTEM ERROR

CODE-92

 

After some poking around/chip re-seating it turned into:

SYSTEM ERROR

CODE-F4

 

I've looked at the manual for CPS Super SALT, but there's nothing mentioning any of these codes...

I've installed sockets for both PIAs (800xl didn't have it socketed), and now both machines are suffering from the black screen, still able to run Star Raiders... lol

I've already ordered a couple pieces of MC68B21P, since I read that these should be functional PIA replacements.

I'm guessing that I managed to fry the good PIA or I'll need to clean the flux off the good chip.

 

Any advice welcome.

[_The Doctor__]

the 800xl was working until you put in the socket for the chip, first place to check is the traces and socket, and the joints. No breaks.... no short.. and no opens from the swipes to the pads and traces...

[apolkosnik]

I've replaced the socket, and cleaned up the pins on the good chip. I found a tiny strand of desoldering braid on one of the pins. It was likely shorting the good PIA. Now both 65xe and 800xl work with the good PIA. The added benefit is that now I have all the memory and the major chips (with exception of Pokey) socketed on 65xe :-)

[+Nezgar]

I spent a long time troubleshooting why I had stability issues with two 800XL's after only replacing the POKEY socket in preparation for stereo upgrades... flummoxed by the issues with the first machine, I started on the 2nd and ended up with the same issue. Turned out that excess leftover flux on the PCB was causing some conductivity between pins I guess, because thoroughly cleaning the area with electronics cleaner and isopropyl alcohol finally fixed my woes. Both have run reliably since.