Using HDD emulator in a Kaypro 10?

[Terry Fox]

Hello all!  I recently purchased an old Kaypro 10, the MFM hard drive has gone bad.  How difficult would it be to replace that 10MB drive with one of these emulators?  I am technically competent, familiar with soldering SMT, using scopes, logic analyzers, etc.

While I am new to the Kaypro machines, I’ve been working with CP/M, Xerox 820, and S100 machines since the beginning.

Thank you,

Terry, N4TLF (formally WB4JFI)

[Piero Andreini]

MFM emulator work like a charm

https://www.pdp8online.com/mfm/mfm.shtm

Piero

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[Terry Fox]

Thank you Piero.  That link doesn’t work for me, but I think I know where it pointed.  Can you tell me if the emulator can emulate more than one drive at a time, like the Kaypro 10 has two 5MB virtual drives (partitions) from the single 10MB physical drive?

I guess that I need to order one of these, but don’t need the SA100x adaptor board.

Terry

[David Gesswein]

I had a report of it working fine a long time ago.
http://www.pdp8online.com/mfm/status.shtml

The virtual drives should work fine since that is CP/M dividing the one drive.

The emulator can emulate two physical drives as long as they share the control
cable. Haven't heard if this works properly with Kaypro.

Yes the SA100x adapter is not needed.

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[Brian Jones]

Can anyone that's used this with a Kaypro 10 share what jumper settings etc they used?  This is the command I used, it does create the drive and I can run the emulator but the kaypro doesn't see it. Not sure if I have a jumper problem or something else :(

cd ~/emu

./mfm_emu  --drive 1 --file ../emufile_a --initialize --cylinders 306 --heads 4

[Terry Fox]

I have one working in a Kaypro 10, but I haven't found the notes yet.  I also need to install another board in a second K-10 soon.  I will post my notes when I find them.  I am also using TurboROM on my working K-10.

I had to increase the value of R13 to about 33 ohms or so, otherwise the Kaypro power supply tended to brown-out and not run (too much inrush current).  That meant it doesn't always boot right up from turning on the power, sometimes I have to hit reset after power on.  But, my power supply may be weak from age.

Terry, N4TLF

[David Gesswein]

FYI: I borrowed a Kaypro 10 to check issue someone was having. With that
computer it started up fine with the 10 ohm resistor. Power supply is the 55W
Astec AA12450. Nothing yet has been done to the supply. Need to replace the
RIFA caps and check the others.

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[David Gesswein]

On Sat, Jan 08, 2022 at 04:09:43PM -0800, Brian Jones wrote:
> Can anyone that's used this with a Kaypro 10 share what jumper settings etc
> they used? This is the command I used, it does create the drive and I can
> run the emulator but the kaypro doesn't see it. Not sure if I have a jumper
> problem or something else :(
>
> cd ~/emu
>
> ./mfm_emu --drive 1 --file ../emufile_a --initialize --cylinders 306
> --heads 4
>

P7 set to drive 2. P8 removed. For format.com specified drive 1,1
Drive in machine was strapped to drive 2.

mfm_emu I used similar arguments to you.

See Kaypro 10 for emulator file I made and some info on the procedure.

http://www.pdp8online.com/mfm/status.shtml