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Opportunistically called "portables," the Kaypro series of computers was released by the corporation whose founder, Andrew Kay, invented what we roughly know as the digital voltmeter. Called Non Linear Systems at the beginning, the computer line quickly took over and became the company's focus. The panel meters and other measuring equipment, available up until just a few years ago, became the sideline business.

The Kaypro series of computers encompassed a wide range of products, from the original "Kaypro" machine with 2 SSDD drives to the Kaypro 10, with a self contained 10MB HDD that was widely known for requiring a smack to start turning, to the Robie, a dual 2.6MB floppy desktop system that was fondly called "Vader's Lunchbox." The Robie is of note due to the poor cleaning of the disk drive heads, considerable diamond grit was left after manufacture and the drives would eat through the proprietary, company formatted disks. Kaypro made a laptop, the Kaypro 2000, and entered into the PC compatible world for a short time.

The Kaypro 2x and 10 were arguably the most successful units, demand being strong into the early-mid 1990s when they simply ran out of parts to keep making them. Both used Kaypro's "Universal board," and in the picture attached you can see where a Winchester drive connector would have been placed. The last hurrah was the late 1990s, when a regional PC manufacturer acquired the Kaypro name to slap on beige box machines.

Non Linear Systems survived for quite some time, and their products can still be purchased in limited quantities from supply houses, but the company itself seems to be gone - their website a psuedo-hacked page with nothing of note.

The system in the picture is mine, with the following specs:

Kaypro 2X + 88, a standard Kaypro 2X with a SWP Co-Power board installed containing an MS-DOS compatible machine.

Z-80 CPU @ 4MHZ with additional 8088 secondary processor 64k on mainboard, 1MB on 8088 co-processor board 9" green CRT, 80x24 text with limited semigraphics capability 300 baud proprietary command set modem, direct connect Battery backed up realtime clock that gets funny after Y2K (It starts counting in Hex) 2 DSDD Tandon Disk Drives, capacity 390k each. Standard Kaypro monitor ROM Full size Centronics parallel and DB-25 serial ports.

The Co-Power board is capable of acting as either a 1MB RAMDisk, or a 1MB MS-DOS machine with about 90% compatibility. The Z-80 CPU is removed and placed on the co-power board, and an adapter module (in the middle of the mainboard) goes into the socket. This unit has performed fairly reliably, but needs the battery removed. The only failure I've had is the disk sync separator IC, marked U21, on the right by the power suppy connector. Symptoms of failure are constant disk seeks while reading. It's been a while since this unit has been on, I'm going to see if it still works sometime later this week.

Material concerning the SWP Co-Power board can be downloaded from here:

https://app.box.com/s/y7htbstvrrva9x6l5zoq3rxt9ps6v0z6

Opportunistically called "portables," the Kaypro series of computers was released by the corporation whose founder, Andrew Kay, invented what we roughly know as the digital voltmeter. Called Non Linear Systems at the beginning, the computer line quickly took over and became the company's focus. The panel meters and other measuring equipment, available up until just a few years ago, became the sideline business. The Kaypro series of computers encompassed a wide range of products, from the original "Kaypro" machine with 2 SSDD drives to the Kaypro 10, with a self contained 10MB HDD that was widely known for requiring a smack to start turning, to the Robie, a dual 2.6MB floppy desktop system that was fondly called "Vader's Lunchbox." The Robie is of note due to the poor cleaning of the disk drive heads, considerable diamond grit was left after manufacture and the drives would eat through the proprietary, company formatted disks. Kaypro made a laptop, the Kaypro 2000, and entered into the PC compatible world for a short time. The Kaypro 2x and 10 were arguably the most successful units, demand being strong into the early-mid 1990s when they simply ran out of parts to keep making them. Both used Kaypro's "Universal board," and in the picture attached you can see where a Winchester drive connector would have been placed. The last hurrah was the late 1990s, when a regional PC manufacturer acquired the Kaypro name to slap on beige box machines. Non Linear Systems survived for quite some time, and their products can still be purchased in limited quantities from supply houses, but the company itself seems to be gone - their website a psuedo-hacked page with nothing of note. The system in the picture is mine, with the following specs: Kaypro 2X + 88, a standard Kaypro 2X with a SWP Co-Power board installed containing an MS-DOS compatible machine. Z-80 CPU @ 4MHZ with additional 8088 secondary processor 64k on mainboard, 1MB on 8088 co-processor board 9" green CRT, 80x24 text with limited semigraphics capability 300 baud proprietary command set modem, direct connect Battery backed up realtime clock that gets funny after Y2K (It starts counting in Hex) 2 DSDD Tandon Disk Drives, capacity 390k each. Standard Kaypro monitor ROM Full size Centronics parallel and DB-25 serial ports. The Co-Power board is capable of acting as either a 1MB RAMDisk, or a 1MB MS-DOS machine with about 90% compatibility. The Z-80 CPU is removed and placed on the co-power board, and an adapter module (in the middle of the mainboard) goes into the socket. This unit has performed fairly reliably, but needs the battery removed. The only failure I've had is the disk sync separator IC, marked U21, on the right by the power suppy connector. Symptoms of failure are constant disk seeks while reading. It's been a while since this unit has been on, I'm going to see if it still works sometime later this week. Material concerning the SWP Co-Power board can be downloaded from here: https://app.box.com/s/y7htbstvrrva9x6l5zoq3rxt9ps6v0z6

(post is archived)

[–] • 2 pts (edited )

circuit here: www.messui.polygonal-moogle.com/comp/kaypro_tm.pdf

/NMI is OR'ed with /HALT not seen that before...

looks like it's coming from the 1793 floppy controller, data/interrupt requests

ah, idea explained here: Fig.1. used here to sync the OR'd INTs with /NMI using /HALT www.trevormarshall.com/old_papers/Floppy_Disk_Transfer_Techniques.pdf using /WAIT would mess with the ram refresh and /HALT doesn't

I guess DMA chips were expensive at the time

. . btw, is there an easy way to strip the google link crap when copying links from its search results?

[–] • 1 pt

( Your first link has an extra char in it, it should be www.messui.polygonal-moogle.com/comp/kaypro_tm.pdf )

That's the Micro Cornucopia Kaypro operation guide. It's for the older model, the Kaypro II / IV, or the 2-83 / 4-83 models. The board in my picture is a 2-84, or the "Universal" board, as it showed up in all models from K1 to K10 after 1984.

That doesn't crack on the guide, tho. MicroC was THE source for this kind of information back in the day and you can probably bank on that guide, even today. The early run of Micro Cornucopia is available on Internet Archive if you have interest, once they left the staple-bound fanzine era of publication and went to perfect-bound glossy, it became more of just another PC mag and no one has much interest in those.

Kaypro machines, by legend, were based on an earlier machine called the Ferguson Big Board (as was the Xerox 820 series.) So it's a case of copying earlier art and yes - DMA was expensive and not necessary for operation.

I don't know of an easy way to sanitize google's crap.

[–] • 0 pt

It's for the older model

yep, I was just looking for any of the circuits, I just collect old Z80 designs

fixed link, ta :)

[–] • 0 pt (edited )

Pretty much all of the circuitry is out there for every variant, if I can find it again I'll shoot you a link. I just need to go back through a few emails and find them.

My first Z-80 device was a Fox microcomputer trainer. I still have it in the office, I'll dig it out. Unfortunately, last time I tried it, it didn't work. It was similar to this: https://pic8.co/sh/2HxEwW.jpg except mine (I think) has the cassette ports on a mezzanine board instead of mounted direct like this one.

[–] • 1 pt

Fascinating; thanks for the backstory.

[–] • 1 pt

What amazes me is the thing still works after 10+ years of no use. You can even get the exact same Panasonic battery.

https://pic8.co/sh/s9Jybb.jpg