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Thread: Kaypro 10 - Serial Port Not Working

  1. #1

    Default Kaypro 10 - Serial Port Not Working

    Hello, I have just joined this group because I became interested in restoring my old Kaypro 10.

    I did put it to use back in the day.

    I showed it to a friend a year ago and discovered it had troubles booting with bad sector showing which slowly deteriorated to all of the A drive becoming bad as I showed this "young" guy what CPM was.

    So, I replaced all the electrolytic capacitors in the power supply, hard drive and floppy (Interesting there are no electrolytic on the motherboard).

    Now it boots up consistently with about 20 bad sectors spread across the four platters.

    I think to fix that I need to do a low level format but first I need to move the existing files off so I can restore them after.

    And this is where my problem is.

    There are two comms files I see on the Kaypro, TERM and MITE.

    TERM works and I can connect it to a PC, press keys on each keyboard and see data on each others screen.

    But TERM it is simply 3 wire comms with no file transfer capability.

    So, that leaves MITE but it simply will not work.

    I know it used to work since I see some BBS logs on the B6 drive and I see MITE on the A6 drive. So I was connecting to various BBS's and using MITE to do it back in the day.

    I found the schematic for this machine and I can demonstrate that the RS232 conversion chips work (that is TXD, RXD, CTS, DTR etc).

    It seems to be a problem right at the SIO chip.

    So I manually jumperd the pins on the serial port to defeat the RS-232 handshake and then I verified they are in their active state at the SIO but it still will not transmit when I press keys. And when I press keys on the PC I see the RXD pin at the SIO chip wiggle but yet nothing on the screen?

    Thinking the SIO chip might be bad I swapped them (there are two on the motherboard) and no change.

    Also, when I change the baud rate in MITE I see the new baud clock coming out of the clock chip going into the SIO chip change so that works.

    And clearly the SIO works where I can transmit and receive data using TERM but not with MITE.

    This Kaypro 10 is in good shape and I have all the manuals (about 7 or so) that came with it so I really would like to fix it.

    Anyone have some ideas?


    Thank you - Steve

  2. #2

    Default

    If Term works, then Mite should work. It might need to be configured again.

    Check that your Baud Rate, Bits per Char, Stop Bits, and Parity are set exactly the same as the PC.
    Typically that is 300, 8, 1 N for testing and 9600,8,1,N for transfers. You can try looping the TX Pin 2 on a DTE Port
    to Pin 3 on the DTE Port to get an echo back. Also Pin 4 RTS can be looped back to Pin 5 CTS, and Pin 20 DTR
    looped back to Pin 6 DSR and Pin 8 DCD. Then when you type, it's echo'd back to your terminal.

    If that works then create a full handshake cable and test with it. You should be able to transfer easily at 9600
    and maybe higher rates.

    I've got Modem904 configured for my Kaypro II, if you want to try that. I wrote the driver for my Kaypro II back then
    following an example I found on a BBS.

    Larry

  3. #3

    Default

    See PCGET and PCPUT for the Kaypro 10 at http://deramp.com/downloads/kaypro/k...20and%20PCPUT/

    Mike

  4. #4

    Default

    Quote Originally Posted by ldkraemer View Post
    If Term works, then Mite should work. It might need to be configured again.

    Check that your Baud Rate, Bits per Char, Stop Bits, and Parity are set exactly the same as the PC.
    Typically that is 300, 8, 1 N for testing and 9600,8,1,N for transfers. You can try looping the TX Pin 2 on a DTE Port
    to Pin 3 on the DTE Port to get an echo back. Also Pin 4 RTS can be looped back to Pin 5 CTS, and Pin 20 DTR
    looped back to Pin 6 DSR and Pin 8 DCD. Then when you type, it's echo'd back to your terminal.

    If that works then create a full handshake cable and test with it. You should be able to transfer easily at 9600
    and maybe higher rates.

    I've got Modem904 configured for my Kaypro II, if you want to try that. I wrote the driver for my Kaypro II back then
    following an example I found on a BBS.

    Larry
    Thank you for your response Larry and for your offer on your Modem.

    I would like to continue with what I have which is an oscilloscope to see the actual data.

    I used to deal with this in my early days at a previous employer and was quite good at it but I guess it is the age thing?

    I believe why Term works and MIte does not is because Term just uses TXD/RXD and does not care about the handshake lines whereas Mite does use the handshake lines and unless they are in the correct active state neither TXD or RXD will work.

    So, I did try the loopback pins but I will review the pins I looped with the pins you mentioned.

    And Pin 6 is not a real DSR rather it is a resistor tied to +5V (active state) according to the schematic.

    Oh, and it is good to know the upper limit of 9600 baud.

    I will report back my results when I get another chance to work on it.



    Regards,

    Steve

  5. #5

    Default

    Mike this is great, thank you.

    And looking at the notes I never thought that it might use the printer serial port so I will check that next time I get a chance to investigate more.

    Although, I think Mite is using the modem serial port because I see this chips baud rate change on my scope when I change it within Mite.


    Regards,

    Steve

  6. #6

    Default

    So, I have tried PCGET and PCPUT and it works well, thank you Mike.

    I believe you wrote this and your instructions were very clear for getting it onto the Kaypro.

    However, I realize I have another problem.

    I thought xmodem would allow wildcards, that is move a bunch of files over but I could not figure out how to do this.

    So, my next question is, how do I move all the files from the hard drive over to my PC without having to copy it file by file?


    Regards,

    Steve

  7. #7

    Default

    Wildcard operations will require Kermit, Modem7, etc. I think I have Kermit on my Kaypro 10, or I might have used MITE initially. I'll take a look tonite.

    Mike

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