Chepponis@CMU-CS-C.ARPA@sri-unix.UUCP (07/31/83)
From: Mike Chepponis <Chepponis@CMU-CS-C.ARPA> A previous post here described well the features/drawbacks of this machine. And while it's true it's not hardware expandable in the sense of buying a board and plugging it in, those who want to do simple hardware hacking can be richly rewarded. The schematics are available from your dealer as part of a package called "The Kaypro Dealer Reference Manual" for $35, or from Micro Cornucopia, PO Box 223, Bend OR 97709 for $20 (and includes a good description of the hardware, too). I have so far brought the 2 spare 8-bit ports of the PIO chips out to connectors on the back panel, giving me 16 bits of I/O with handshake. I use these to connect to a Touch Tone converter, send morse code with the keyboard, test various parts of a Repeater Controller I'm building for ham radio group, etc, etc. They've been very useful, and was done with no permanent electrical changes to the circuit - by using solder-type 40 pin sockets & connecting wires to the sockets & sandwiching my sockets between the PIO chips & the board sockets. Easy, useful mod. I've also added reverse video (black chars on green background) by adding only a 3-input NOR gate. I'm now thinking about full bit-mapped graphics. I'm doing the 5MHz mod as well (detailed in "Micro Cornucopia") which involves only replacing the Z80 with a Z80B, changing the 2716 boot rom to a 2716-1 rom, and pulling off 5MHz from the divider chain before it become 2.5 MHz. So, the machine is amazingly simple to hardware hack. I have also taken it many places & (accidentally!) bumped it many times, but it always works like the day I got it. I like it....comments, etc to chepponis@cmu-cs-c. -Mike -------