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Thread: KAYPRO 4 only Lower case

  1. #1
    Join Date
    Dec 2013
    Location
    Illinois, USA
    Posts
    22

    Default KAYPRO 4 only Lower case

    Hello everyone.

    I am stumped. I just got a Kaypro 4 and everything displays in lower case. When I press the caps lock key on the keyboard the LED in the caps lock key lights but I still only get lower case.

    When I hold shift on either side of the keyboard also only lower case.

    Anyone have any ideas what the problem could be?

    Thanks!

    Bill

  2. #2
    Join Date
    Aug 2013
    Location
    Philadelphia,PA area
    Posts
    115

    Default

    Sounds like bit 5 (32) in video memory is stuck High. Instead of displaying 0x41 (A), your displaying 0x61 (a), etc.

    Tom

  3. #3
    Join Date
    Dec 2013
    Location
    Illinois, USA
    Posts
    22

    Default

    Tom, I think you are right. Is the video memory socketed so I can fix it?

    Any way to fix it?

  4. #4
    Join Date
    Mar 2013
    Location
    Chaffee, MO
    Posts
    1,347

    Default

    Sure you can fix it, but you need to do a few tests first. Download the Manual for the 4, and then print out the
    ASCII Chart on Page 17-1 (of the 1984-F_Technical_Manual). Once you have that, start with the Character
    that is Decimal 32 (SPACE) and type it to see if that is what you get. Do all characters down through Decimal
    126 (~). Make a note of all that are incorrect. If it's just the "A" being "a" then it's likely the Character EPROM.
    If there are more characters (and numbers) that are incorrect, then it's likely associated with the Date Bus (D5 Bit).
    A = 0x41 = 0100 0001 (MSB to LSB)
    a = 0x61 = 0110 0001

    Hopefully it's just the "A" being displayed as the "a". Your tests will tell the tale.

    There are Diagnostics out there for the Kaypro's. I wrote one such ZIP back in the day.........
    WOW, it's been almost 40 years ago.

    Larry

  5. #5
    Join Date
    Dec 2013
    Location
    Illinois, USA
    Posts
    22

    Default

    Thanks Larry!

    I got lucky. I took the cover off and as you face the KP4 I started on the left side of the motherboard and removed and reseated all the socketed chips halfway and stop at the last BIOS chip. I then decided to power the KP 4 and see if it made any difference. And Voila! All the characters are now displaying in correctly and in CAPs where its supposed to be.

    Now I would like to figure out which chip it was that when reseated fixed the problem.

    I ran the KP4 digs you gave me but it locks up my KP4. So I went to the site you gave me and downloaded it there and same thing. I copy Nevada COBOL and that works so its not the KP4 but something with the diags.

    Any ideas?

    Thanks

    Bill

  6. #6
    Join Date
    Mar 2013
    Location
    Chaffee, MO
    Posts
    1,347

    Default

    Bill,
    Nope, you may have to try a different set of Diagnostics. I've not tried all of them, since I only have a Kaypro II.

    Larry

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