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View Full Version : Kaypro 10 and 2X 256K RAM upgrade



Alphasite
October 10th, 2017, 07:01 PM
I've found a couple of files describing a 256K RAM upgrade for the Kaypro '83 systems and a reference to one for the '84 systems but I can't find the actual instructions for the upgrade. I have a 10 and 2X both with the new fully-populated boards that I'd like to upgrade so I can run a banked CP/M Plus and/or a RAMdisk.

Does anyone have a copy of the instructions?

durgadas311
October 11th, 2017, 05:14 AM
I describe a modification I made to my 2X back in 1985 here: http://sims.durgadas.com/kaypro/kaypro84x.html, that is probably one of the references you are making. Unfortunately, the details of what I did are either lost or buried under a bunch of scratch paper notes in a basement somewhere. I had to cut traces and run jumper wires, and I used some spare sockets and gates on the board. I had drawn a schematic (later translated into kicad) with the idea of building a plug-in board to do the same thing in a cleaner way. The 256K mod is long gone as I stressed the mainboard too much and it failed about a year later. I never tried the modification again on the replacement mainboard.

My old Kaypro is barely functional these days. But I know there have been many add-ons created for Kaypros, both back in the 1980's and in modern times. Perhaps someone here can point you to something to expand the memory. I certainly think running CP/M Plus is a worthwhile goal, I find it hard going back to CP/M 2.2. I've also got some add-ons to CP/M Plus for networking (CP/NET) which might be of interest.

ldkraemer
October 11th, 2017, 05:42 AM
Eric,
I sent you an Email with the Article out of Micro Cornucopia Issue #30. There may be responses in later issues. I'll look through
the other issues as time permits.

Does your 2X have the Drivetec Drives or Standard Floppy's? What ROM is on your Motherboard?


Larry

Alphasite
October 11th, 2017, 03:12 PM
Eric,
I sent you an Email with the Article out of Micro Cornucopia Issue #30. There may be responses in later issues. I'll look through
the other issues as time permits.

Does your 2X have the Drivetec Drives or Standard Floppy's? What ROM is on your Motherboard?


Larry

It has the Epson drives. It came with an OmniLogic ROM as it was customized (but the extra hardware was removed). I burned a KayPro 2X ROM to test and then a KayPlus ROM. Since I plan on sticking a FreHD in it I'll need to switch to the TurboROM.