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Thread: KAYPRO and KayFreHD as a hard disk module

  1. #11

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    Please let me know - I'll take at least one. I haven't used my Model 4 in years, but having a FreHD that would work with either my 4/84 or my 10 would make them a LOT more useful.

    tnx.

    g.
    Proud owner of 80-0007
    http://www.f15sim.com - The only one of its kind.

  2. #12
    Join Date
    Feb 2009
    Location
    Chattanooga, TN - USA
    Posts
    853
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    I don't have a kaypro yet, but it would be worth having a spare converter board in case I ever do.


    Later,
    dabone

  3. #13

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    I'm interested in this from jaquinn.

    >If you are using a 4/83 (and hopefully the 2/83 - Tez - Phil Avery is going to lend me his for testing) the approach that requires least modification to the machine is a piggy back adaptor
    >board with both a ROM and Z80.

    >This is required because the ROM on the /83's is too small and doesn't have sufficient decoding on the main board to support the KayPlus firmware.
    >Also because there is no expansion connector like the /84's.


    >This is the approach I took when Frank and I were working on the project (because I have a 4/83). I built a single adaptor board that plugged into the ROM and Z80 sockets.
    >It does require two additional wires to be soldered to one other chip on the main board but is easily reversable if you want to return the machine to "stock" configuration.
    >The connector on this adaptor allows a "TRS-80" FreHD to be used with a straight through 50 pin cable.

    I've got a FreHD for the TRS-80 Model 4, which I haven't yet assembled. Actually I am quite happy with my TRS-80 model 4 with floppies at the moment. Both drives work well and I tend to like my computers as original as possible.

    However, on my Kaypro II, one of the drives is dicey. If I could mount the FreHD card inside (with the piggy back adapter board) and tap into internal power (maybe with the power plug that presently goes to a drive) then this is something I'd want (depending on the price of the board and components of course).

    One question. Does the board on a Kaypro make the machine think it's connected to a hard disk, or two floppy drives (using floppy disk images of course). I'm just trying to ascertain that with the Kaypro II, you'd get the same experience as if both disk drives were working (or not)?

    Tez
    ------------------------------------------------
    My vintage collection: https://classic-computers.org.nz/collection/
    My vintage activities blog: https://www.classic-computers.org.nz/blog/
    Twitter: @classiccomputNZ ; YouTube Videos: (click here)


  4. #14
    Join Date
    May 2012
    Location
    Auckland, New Zealand
    Posts
    90

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    One question. Does the board on a Kaypro make the machine think it's connected to a hard disk, or two floppy drives (using floppy disk images of course). I'm just trying to ascertain that with the Kaypro II, you'd get the same experience as if both disk drives were working (or not)?
    The Kaypro sees the FreHD as a hard disk drive. It will boot from the FreHD so even if both your floppy drives fail you can still run the machine. You can configure your floppies as different drive letters depending on your preference. This is all due to the KayPlus ROM... documentation is available at http://www.microcodeconsulting.com/z80/kayplus.htm

    You really should get your FreHD built for the Model 4. It will change your life (well as much as this sort of technology can). FreHD on the Model 4 connects to the external expansion connector with no mods required (unless you want autoboot) so you can keep a completely stock machine.
    SBC6120 / PDP11 + VAX / TRS-80 / Kaypro / Northstar / Home Brew Z80 / BBC / Amstrad / Commodore
    http://www.quicktrip.co.nz/jaqblog

  5. #15

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    I think I need two FreHDs Andrew, one for my Kaypro II (permanently inside) and one free-standing one for the TRS-80 Model 4. Then of course there is my System 80 and Model 1 to think about (-:

    Seriously though, these are wonderful devices and it's great to see the work you guys are doing for drive replacements on the old Z80 gear.

    Tez
    ------------------------------------------------
    My vintage collection: https://classic-computers.org.nz/collection/
    My vintage activities blog: https://www.classic-computers.org.nz/blog/
    Twitter: @classiccomputNZ ; YouTube Videos: (click here)


  6. #16

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    For all older Kaypro's (2/83, 4/83, 10(w/o modem)) you have to have a 27C64 (8Kx8 ) EPROM to use the KayFreHD.
    Also for the use of the KayPlus ROM without using the Hard drive feature, you need a EPROM adapter board.
    Such a board i gave in production (10 items) and it arrive in about 10 days.
    The board features the use of up to an 32Kx8 EPROM/EEPROM, so up to four ROM-images can be choosen by change the jumper setting.
    The EPROM socket position on the Kaypro mainboards vary in position relative to the Z80 socket, so i don't combine it with the Z80-I/O adapter board.
    Depending on the mainboard there are wire connections necessary, which grabs needed signals that not available from the original EPROM socket.
    On Kaypro 2/83 one wire from U60 pin 14 and two wires from U59 pin 2&5.
    On Kaypro 4/83 one wire from U60 pin 14 and one wire from U59 pin 5.
    On Kaypro 10(old) one wire from U48 pin 10.
    Frank
    EPROM_256_top.jpg KayFreHD_bot.jpg

  7. #17

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    I've actually tried the KayPlus ROM, but there's some kind of bug with the MOVCPM that comes with the version of CP/M I have for the 4/84 and it won't allow me to shrink the TPA in order to sysgen a KayPlus boot disk.

    Can the FreHD work with the Advent Turbo ROM as well?

    g.
    Proud owner of 80-0007
    http://www.f15sim.com - The only one of its kind.

  8. #18

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    Hello Geneb,
    yes, this works also with the Advent TurboRom.
    Unfortunately only the TurboRom for the 84 is available. Searching for the 83 version of the ROM going on.
    Frank

  9. #19

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    My Kaypro 2X has a 21/84 board. All I need to do is solder a connector to J9 to use the KayFreHD?
    Attachment 16732
    Thanks,
    Rick

  10. #20

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    Just a plug.

    Those of a technical bent interested in FreHD and FreHD development should definitely read jaquinn's experiences in his blog here:
    http://www.quicktrip.co.nz/jaqblog/

    Great stuff!

    Tez
    ------------------------------------------------
    My vintage collection: https://classic-computers.org.nz/collection/
    My vintage activities blog: https://www.classic-computers.org.nz/blog/
    Twitter: @classiccomputNZ ; YouTube Videos: (click here)


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