Erik_
I added some more solder as well as reflowed another spot
Wed Sep 07, 2022 9:31am

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 as well.

I got some info on how to simulate the shift button being pressed and used some jumper wires to set it on the socket:


That worked!


Someone suggested checking the pins on the keyboard to make sure it was registering button presses now that we knew what pin it was.
So, I put my ohm meter on pins 8 & 9 (shift). Without anything pressed it showed open (expected). Then, pressing the shift key I noticed it was actually reading a value! I moved the keyboard around and it still showed a value when shift was pressed. I want to say the value was ~60k ohm when pressed but not sure.

I plugged it back in and it was working again. Played with the computer a bit and had some issues with it stopping randomly. I unplugged and plugged it back in and it worked again. Finally, after a couple of those, it stayed working. That's when I wrote the Wry test app. I also played a few rounds of Star Raiders without any issues.

I think it must be the KB socket pin 9 isn't making the best connection and it randomly flakes out. Pin 9 is the only shared pin between Ctrl, break, and shift.

Seems to be working now. I'm worried about putting it back together and having it stop again but I guess I should at least try it for a bit.

Hopefully you can take it apart without tons of little springs or other such troublemakers popping free.

I actually had that happen with the switch that turns the computer off when the cartridge door is opened. It popped right out of the switch. I don't think it's possible to get it back in though. It's a complex little buckling connector thingy and the spring is a "U" shaped tab of metal that was wedged in there somehow. I think I'm going to have to wire that switch as "always pressed" and rely only on the side power switch to turn the computer on and off. Unless another switch can be found but I'm not sure of that without getting another power board.



  • 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
    • I added some more solder as well as reflowed another spot- Erik_, Wed Sep 07 2022 9:31am
      • 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