Erik_
Additional updates.. not quite there yet.
Tue Aug 23, 2022 4:03pm

Currently, everything seems to work except SHIFT, CTRL, and BREAK on the keyboard. I noticed the keys sometimes going in and out with working an not. I thought it was the ribbon cable but on a hunch, I pressed down on the POKEY chip while the computer was on and tried again. Lo and behold the keys started working again. Each time they stopped, pressing down again on the POKEY brought them back to life.

Looks like even with all my cleaning, the POKEY chip isn't making good contact with the IC socket. I'm guessing there's some corrosion still deep in there. I was going to just desolder one from my 5200 but decided to pick up a pack of different sized ones for super cheap on Amazon instead.

New sockets should be here tomorrow so I'll be able to see how much that fixes.

I think the shift, ctrl, and break keys are unrelated as they're all on the same output pin. I can't figure out how to jump the pins on the main board's connector to simulate a key press for those though. Using a jumper wire, I can get other keys to be pressed.

  • New PIA chip in and it works! (-ish... updated) - Erik_, Wed Aug 17 2022 2:46pm
    New PIA chip came a day early in the mail today. I quickly cleaned it up and put it in the computer during my lunch break. New chip: Old chip: I loaded up Pac Man and the joystick now worked perfectly! Awesome! I didn't really have time to play around with it much. I just had time to run... more
    • Additional updates.. not quite there yet.- Erik_, Tue Aug 23 2022 4:03pm
      • New POKEY socket installed - Erik_, Thu Aug 25 2022 10:21am
        Getting the old one out was a bit of a chore but not unexpected being that it's been happily in that spot for 40 years. Thankfully awhile ago I picked up some copper solder braid and a spring loaded solder "sucker" thing. The solder sucker was a big help. I also fluxed the hell out of the pins to make... more
        • Wow, looks good. I bet you can't get the same quality conne - Puckdropper, Sat Sep 03 2022 3:30am
          connector any more. I see what you mean about needing a bit more solder. Those jumper wires can be tricky, they seem to have a mind of their own. I wonder if the keyboard is suffering from the same corrosion that affected the socket? Maybe it was the way in? Hopefully you can take it apart... more
          • that a guy on the AtariAge forum suggested. It didn't change anything but at least the chip socket is soldered in there better. Yeah, I think it was a combination of the two sockets. The POKEY socket was making a bad connection from corrosion and then the keyboard socket is making a bad connection... more
            • 60 kOhm seems too high. - Puckdropper, Thu Sep 08 2022 6:03am
              Usually pullup resistors are 5-10k, but I'd think your keyboard should read either infinite ohms or 0 ohms with respect to ground.
              • on my meter. It's sort of an "on/off" type of thing. (Need to replace it). Final solder job with some reflowed and flux cleaned off. There's two pins on the left side that look like they could use a tiny bit more solder but I think it might be okay. Cartridge slot switch bypass jumper soldered... more
                • Is it just my angle or is there a bridge on the right-hand s - Puckdropper, Mon Sep 12 2022 11:36pm
                  side above the jumper resistor? A trick with dirty switches is to move them back and forth a bunch of times, like 100 or more, until the contacts clean themselves off. If it's one of the more open types, you may be able to squirt some CRC 2-26 (from Home Depot) in there to help clean the contacts.... more
                  • I think it might be a piece of paper towel - Erik_, Tue Sep 13 2022 1:53pm
                    from me wiping the rubbing alcohol off. Yeah, I've flipped it a bunch and cleaned it with CRC QD Electronic Cleaner. It's much better than it was. Probably just needs some more "back and forth". I think it is that keyboard connector. I just took a few minutes and removed the 4 screws that hold... more
                    • Is it just a ribbon cable? - Puckdropper, Thu Sep 15 2022 4:30am
                      I never got the tools to properly work with one, but they're pretty straight forward. You can probably put a new end on by smashing it into a new connector, but who knows how good of termination you'd get. If it's like an IDE cable, it's just headers and sockets.
                      • Sort of... - Erik_, Sat Sep 17 2022 12:44am
                        Here's a pic I found online It's more like through hole IC pins on a "ribbon" like cable. I could solder another connector that plugs into the board onto these pins but might be easier to replace the socket on the board first.
                        • I see. It does sound easier to work on the board first - Puckdropper, Thu Sep 22 2022 5:10am
                          Hopefully that's where the problem is. I think I saw something like that on a "make it a 286" chip upgrade. You pulled the 8088 out of the motherboard and plugged it into the board. You could then switch via a toggle switch between your 8088 and 80286. Of course the cable is missing on mine!
"Forces act when not restrained" - Puckdropper