Keyboard models

Note KSN means Keyboard Serial Number

Remember that Keyboards are one of the easiest items to switch from one machine to another. Do not be too dogmatic about the serial numbers attached to a particular machine.

Note about Serial Numbers near #4000 - #5000: I have found that a white thread locker was applied. If you have one of these machines only use an Anex 3980 +1 X 75 Phillips Screwdriver. If any screw appears to "Cam Out" stop immediately and hammer the Anex into the screw head before trying to remove the screw further. Other wise you will likely need to use a 1/8 inch Left Hand drill bit to remove the screw head. Carefully remove top of case. From the inside of the case us a ENGINEER PZ-58 Screw Removal Pliers to back the screw out as far as it will go then use the PZ-58 from the outside to remove the screw.

Non destructive exam of Keyboard

I have tried to look for a reliable way of knowing which mechanical keyboard is with each CPM Kaypro machine. After reviewing my collection I can only find 3 manufactures of CPM Kaypro keyboards. SMK, Keytronics and Maxi-switch. All three manufacturers mostly kept the same design throughout the entirety of the CPM machines.

Sometimes from a picture of the keyboard you can determine the mechanism. If the G key also says BELL then it should be a Maxi-switch keyboard.

Also, if you have a type A keyboard (see below) you have an early SMK keyboard.

To non-invasively determine between an Keytronics and type B SMK keyboard, unlatch the keyboard off of the machine’s body. Place the keyboard in front of you like you would type on it. Tilt the keyboard so the “Kaypro” label comes towards you. Depress the space bar. Look in the space between the front of the spacebar and the metal keyboard cover.

If you see two metal bars coming from the front of the space bar the keyboard is an SMK mechanism.

If you can’t see the bars and the G key doesn't say BELL then it is a Keytronics mechanism. The Keytronics is the only mechanism with the foam and foil system which would likely need to be rebuilt if it is still original.

General data

Based on the 63 CPM Kaypros that I have here is a breakdown of which type of manufacturer made each mechanism:

Notes: There are no known machines in the 160-180K range. With the exception of one blip in the data the Keytronics (foam and foil) keyboards ended in the 40K area.

Keyboard Mechanisms

SMK

SMK Keyboard Models C, D, E, and Z (Tactile)
	Found in Type A Found in #2775 - KSN 028401404#8409 - KSN 10820673, #12275 - 11821370, #12654 - 12822711, #13480 (Irregular) - KSN 058306857, #15453 - KSN 12823872, #16679 - KSN 12825061, #43168 - KSN 12824823 (Kaycomp Keyboard) Type B #16288 - KSN 01838471,#17083 - KSN 12827743, #23201 - KSN 01839675, #27336 - KSN 03837134 #42891 - KSN 048304571 (Label 4499 09/13/83), #43486 - KSN 078401557, #45618 - KSN 03839356 (Label 1637 03/21/83), #46750 - KSN 058307701, #47027 - KSN 058307879, #48004 - KSN 058312392, #48968 - KSN 058312974, #57145 - KSN 02832653 (Case stamped (Mar 2? 19?? likely 1983), #84724 - KSN 078322869, #85815 - KSN 068402233, #59823 - KSN 068402084, #60021 - KSN 03830258, #69280 - KSN 068319445, #96308 - KSN 988301826, #98193 - KSN 098305971, #98465 - KSN 098305790 (Label 2147 04/29/83), #98522 - KSN 0(5or6)8314946, #101536 - KSN 078321652, #127311 - KSN 038410909, #128620 - KSN 018405958, #129891 - KSN 038407222, #148830 - KSN 078325471, #250925 - KSN 128302373, #273643 - KSN 128303533, #288536 - KSN 068406464, #405393 - KSN 068400434, #423193 - KSN 088302693 Unknown Serial Number - KSN 108300884 (German Keyboard)

Keytronic

Keytronics Keyboard A65-02207-2O1D (Capacitive)	Found in #3590 - KSN 05420, #4207 - KSN 50845 (8/82), #4222 - 50996 (8/82), #4223 - KSN 55080 (8/82), #7954 - KSN 44011 (10/82), #20250 - KSN 06229 (1/83), #21460 - KSN 06317 (1/83), #36960 - KSN 09635 (9/82), #209236 - KSN 34770 (6/83)

Keytronic Keyboard Rebuild

tex ELEC Foam and Foil pad kit

Adrian Black's TRS Foam and Foil Replacement

Maxi Switch

Maxi-Switch Keyboard 2160150 (*)=2160171 (Tactile)	Found in #73356 - KSN 11323 06/09/1983, #76797 - KSN 017270 07/30/1983, #93481 - KSN 8760 04/08/83, #97390 - KSN (*)7750 08/02/83, #99393 - KSN (*)5777 07/30/1983, #102622 - KSN , #136044 - KSN (*)028791 12/19/83, #138472 - KSN 013751 03/26/84, #141562 - KSN (*)022453 11/18/83, #143892 - KSN (*)021975 11/17/83, #147533 - KSN (*)023551 11/22/83, #204928 - KSN (*)030248 12/22/83, #208048 - KSN 015350 06/30/83, #240019 - KSN (*)026620 12/12/83, #275940 - KSN (*)027827 11/02/84

Type A vs Type B Keyboard

On early machines (around #8,000) There exists two types of Keyboards. In an early article they are defined as Type A and B. It turns out that this is a key indicator of who manufactured the keyboard and if it is a tactile switch or foam and foil keyboard. SMK appears to have only made the type A keyboards with tactile switches in the early days. Keytronics made the Type B keyboards with a foam and foil keyboard that degrades over time.

From the November 1983 Issue of Radio Electronics

	Type A	Type B
External View	SMK	Keytronics
Internal Key View	SMK	Keytronic Early SMK Later SMK
Board Appearance	SMK	Keytronic SMK
Parts		Type B is a single piece

Prototype/Sample Keyboard

The image below is of the demo/marketing Kaycomp machine. Notice on the keyboard that there are 5 screws on the side and possibly 4 in the top.
It appears that the keyboard case was made of more parts than the mass produced keyboards. It also appears to be a little taller.
Of the five screws on the side the top two appear to be slightly smaller.
The 4 on top are likely the screws holding the keyboard mechanism in place. (The mass produced keyboards mount the keyboard mechanism to the bottom on the keyboard case.)

*

Keyboard Close Out

In the June 1988 edition of Profiles this ad ran on page 41. There must have been a surplus of the keyboards in inventory and Kaypro was ready to move on to the DOS based systems.

Brown Kaypro Keyboard

In Spring of 2025 a batch of Kaypro based Keyboards appeared on eBay. They had brown keys rather than the traditional colors. Having bought the first one from the seller I tested the keyboard with a Kaypro and it was fully functional. The seller had 100 listed for sale when I bought mine. See below for the story given to me by the seller.

"This inventory of new MaxiSwitch keyboards, used for the Kaypro II originally, we're purchased from MaxiSwitch directly back in 1983 by a local computer hardware manufacturer, in turn, became our client a few years back. We have finally got to some of the inventory to list on our back burner. He was using these MaxiSwitch keyboards for his own computer system he was developing, but sadly was overshadowed by the moving technology breakthroughs at the time, which ultimately put him out of business." (Ebay seller in a message to me.)