• Amiga 500 Keyboard Cursor Key Problem

    From Bioquake@80:774/68 to All on Fri Mar 27 18:36:56 2020
    Hello!

    I have recently become the proud owner of an Amiga 500!
    It's a wonderful machine, but I have one small issue.

    The issue being that the Cursor Keys and the Help key are not working the way they're supposed to. This is going to be somewhat of a long post, so please bear with me here while I try to explain the problem in as much detail as possible.

    I've taken a few days to diagnose the problem. The keyboard is one of the Mitsumi kind. I've checked the continuity of the pads on the membrane, they conduct just fine. The keys themself are not the problem either, they are perfectly functional, too.

    I have narrowed the problem down to the keyboard Control Board situated at the top right of the keyboard. Measuring the connections between the parts on the board reveals that there are no connectivity issues there either.

    The Cursor keys and Help Key tend to work only when softly pressing on the white connector that connects the keyboard controller to the membrane, y'know, the one where you stick the membrane into. When the white connector is softly pressed from the top, the cursor and help keys work exactly the way they're supposed to, but letting go of the connector makes them faulty again.

    Any idea what might be the cause of this issue? Should I just replace the connector, or should I replace the membrane? I've tried everything, and I'm out
    of ideas at this point.

    Thanks for taking the time to read this through, any suggestions would be much appreciated!

    Kind regards, BioQuake.


    cb caBioquake

    --- CNet/5
    * Origin: Badass Amiga Board aBSiNTHE BBS absinthebbs.net:1940 (80:774/68)
  • From Bioquake@80:774/68 to Bioquake on Mon Mar 30 11:18:56 2020
    Well, I seem to have fixed the issue.

    I reflowed the solder joints of the Control Chip on the keyboard's motherboard.
    It seemed there were tiny cracks in the solder joints that would create a connection when gently pushing on any part of the board.

    Glad the issue is fixed!


    cb caBioquake

    --- CNet/5
    * Origin: Badass Amiga Board aBSiNTHE BBS absinthebbs.net:1940 (80:774/68)
  • From Anachronist@80:774/68 to Bioquake on Tue Mar 31 15:08:15 2020

    You know as I read your write-up of the issue, I was getting ready to respond about reflowing. In our chat I had completely missed the part about the connector. Great work troubleshooting and fixing the issue!

    cb cdaNACHRONiST c1| caabsinthebbs.net:1940q1



    z0cA.z0cFz0cA------------------------------------------------.z0

    z0cA|z0cD We now return Control of your Modem to you.... z0cA|z0
    z0cA`------------------------------------------------'z0

    --- CNet/5
    * Origin: Badass Amiga Board aBSiNTHE BBS absinthebbs.net:1940 (80:774/68)