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Thread: Early Sol-20 Restore

  1. #1

    Default Early Sol-20 Restore

    A couple weeks ago I applied ECO 1000 - 1002, crowbar, to a recently acquired early Sol-20 with an original regulator board. With deRamps diagnostic assistance I replaced the TIP41, placed a 100k resistor in parallel with R12. Also replaced the power push button - there was a funky installed toggle switch and the power inlet jack too.

    After repair;

    • ~300ma load 5.056vdc
    • ~2.0 amp load 4.914vdc


    Previous to the R12 parallel mod I was sitting at a low 4.646VDC with a 2amp load.
    There is a noticeable improvement in the, now lower, sensitivity of the 5vdc now that I've installed the crowbar mod.

    ECO10001.jpg

    I installed the power supply, fired it up and way cool! Got a prompt. And two or three keys also worked! That's another story...

    PromptWithFewWorkingKeys.jpg

    Stay tuned for keyboard saga.

    c ya... - Jeff
    KF7CRU
    @jhalbrecht
    @theRetroWagon

  2. #2
    Join Date
    Nov 2012
    Location
    Richmond Hill, Ontario, Canada
    Posts
    884

    Default

    That is great. Have any full pics of the Sol-20?

  3. #3
    Join Date
    Dec 2013
    Location
    Near Milwaukee Wisconsin
    Posts
    868

    Default

    I also have a Sol 20 that has keyboard issues. Hope to see how you correct this.
    IMG_1031x.jpg
    Mike

  4. #4
    Join Date
    Nov 2012
    Location
    Richmond Hill, Ontario, Canada
    Posts
    884

    Default

    Quote Originally Posted by Mike_Z View Post
    I also have a Sol 20 that has keyboard issues. Hope to see how you correct this.
    Mike
    You'll have to replace the foam pads within the Keytronic brand keyboard.

  5. #5

    Default Sol-20 Keyboard Rebuild

    Stay tuned for keyboard saga.
    RemainsOfTheDayOfTheKeyboard.jpg

    This picture should be worth more than a thousand words about the keyboard repair. I'll be preparing a blog post about this in the not to distant future. Meanwhile in this image you can see the

    • Completed keyboard before reassembly. It works!
    • Sun keyboard I scavenged the new plastic, foam and Mylar assemblies from.
    • A piece of galvanized pipe I turned in my lathe to make a jig to cut the double sided tape and align the plastic for attachment.
    • Some of the old deteriorated Mylar assemblies


    Check out the screen. I entered some data in RAM and dumped it out. Then typed every key and upper / lower of special characters.

    Sol-20WithAmdekBeforeReAssemble.jpg

    This is an early Sol-20 and apparently KeyTronic made at least two versions of the keyboard. This one appears to have used double sided tape to attach the assemblies to the bottom of the keycap assemblies, that's how I reattached. Later versions had the plastic disc snap in place. I'll get together detail of the two types you can see how the later parts have a clip to catch the plastic disc which is much less labor intensive to rebuild.

    c ya... - Jeff

    KF7CRU
    @jhalbrecht
    @theRetroWagon

  6. Default

    Quote Originally Posted by Mike_Z View Post
    I also have a Sol 20 that has keyboard issues. Hope to see how you correct this.
    IMG_1031x.jpg
    Mike
    http://www.sol20.org/keyboard.html

    Not hard to do. Be sure to also check the link that is within this link.
    where did the blinky-binkys go?

  7. #7
    Join Date
    Dec 2013
    Location
    Near Milwaukee Wisconsin
    Posts
    868

    Default

    Thanks for the pointers. I hope to tackle this job as soon as the snow flies around here. Till then I'll watch what you guys are accomplishing. Mike

  8. #8

    Default Load and execute

    Fun!

    I entered XEQ<CR> and pressed play on my Zoom H4N handy recorder. The Sol-20 loaded Life and later Hangman and executed the program. I want to verify that the motor control circuit and relay work and test the serial port. Then I'll button it up and reclaim my dining room table.

    XEQ-Life.jpg

    Life.jpg

  9. #9

    Default

    I currently have a Sol keyboard open, too. Much of the foam seems to be holding (barely) but a few pads have fallen apart. I was puzzled to find the adhesive membranes after reading much about the "snap-in" disks. They are more flexible and thinner than double stick tape.

    IMG_0327.jpg

    It looks like the metalized disks are semi-transparent where the LEDs are?

    I'm not sure what I'll use for the adhesive film. I don't have a Sun keyboard, so I'll be punching out my own replacements.

  10. #10
    Join Date
    Feb 2015
    Location
    Cleveland, OH, USA
    Posts
    504

    Default

    Common problem with Kaypros, too.

    -CH-

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