Jump to page content

Cherry M4/M5/M6 part number schema

The following page provides known details of Cherry M4/M5/M6 part numbers. See also the Serie M7 schema.

See M7 examples for examples found to date.

Contents

Sources

This page lists only the parts found in official Cherry catalogues and advertisements. See parts for a parts list that includes unconfirmed types. The information below is sourced from the following:

See Cherry catalogues on the Deskthority wiki for copies of this literature.

Still required

Overview

It appears that no formal schema existed, and that part numbers were simply assigned sequentially in most cases. For example, 10° stem can be denoted by +10 (as with all the types in the 1973 catalogue, such as M61-0100 and M61-0110) and by +1 (as with M41-0126 and M41-0127). The one known tactile type has non-descript part number M51-0229. However, there are a number of commonalities.

It appears that the T stem was not introduced until later; no mention was made of stem shape in the 1973 and 1974 catalogues, while in 1979 multiple stem shapes exist. The drawing for Burroughs M51-0131—formerly M51-0139—shows a T stem and dates back to 1973, but with nine or ten documented revisions and a Style B shell depicted by the end of the revisions, one cannot be sure what the original looked like. It is not keycap-compatible with normal 12 mm keystems, and it is not clear what led to the introduction of T stems from Alps and Cherry by the end of the 80s. What we do know from the 1985 EEM advertisement is that M61-0120 (0° T) replaced M61-0100 (0° straight).

It is possible that the huge rise in configuration options led to an explosion of non-standard part numbers; that is, it was not possible to define a schema for options not conceived when the series was introduced. (Later options included two extra illumination methods and multiple keystem designs.)

Note however that Style A, AB and B switches with T stems are limited to single pole momentary configuration. The corbel for the T vane of the keystem runs right down inside the slider, and does not leave room for the second pair of contacts (the sliders can only operate one set of contacts). Based on patent drawings, such switches do not leave room for the alternate action mechanism either, which is why B70-05AB has T switches for momentary keys and bar (straight) switches for the lock keys.

By comparison, the style C and D slider from the German Serie M7 switches is significantly slimmer and supports dual contacts in addition to T and cruciform keystems.

Part number format

Part numbers follow this form:

MSC-0TAB

The positions are as follows:

Position Code Suggested meaning
1 M M: keymodule
2 S Subseries (4, 5, 6, 7); no values below 4 are known to exist, and 8 and above were used for entirely new switch series
3 C The number of contact pairs; this has only been seen as 1 or 2
4 0 This is always zero in known types
5 T Nominally this indicates the switch type; see the subtypes table below for details.
6 A Undefined
7 B Undefined

Subseries

M4 is the illuminated type. M5 and M6 are not clearly separated. The following table describes the known switch characteristics within each subseries according to the catalogue listings.

M7 is not part of this series, but it was advertised in the US, presumably due to the need for centre illumination that was not offered by M4.

Subseries Stem Force Angle Contacts Action Illumination
M4 Straight, round Various 0° and 10° 1A Momentary and alternate Corner
M5 Straight, T Various 0° and 10° 1A, 2A Momentary None
M6 Straight, T Various 0° and 10° 1A, 2A, 1A+1B Momentary and alternate None

Subtypes

The following table lists suggested subtypes based on the catalogue listings.

Subtype Usage in 1973–74 Usage in 1979–82
0 Unused Various switches; this includes the mechanical shift lock assembly switches formerly in subtypes 3 and 5
1 Standard switches Various switches
2 Unused A handful of assorted switches: the one tactile type, two of the space bar types, and one of the 6 oz switches
3 Used for the shift switch in a mechanical shift lock assembly Unused
4 Unused
5 Used for the shift lock switch in a mechanical shift lock assembly Unused
6 Unused
7 Unused
8 Alternate action
9 Only found in the part number of the only 1A+1B switch (from 1974)

Catalogue types

The following is the list of known types from the 1973, 1974, 1979 and 1982 catalogues and the 1985 EEM advertisement. The descriptions are verbatim per the 1979 and 1982 catalogues. Illumination type and notes are extra to the catalogue.

“✗” denotes parts that are listed as discontinued in the publication in question.

Two M7 types are listed, simply because these were advertised in the US alongside the US-made types.

The weight ranges indicate tolerance. For example, M71-0100 was listed in Germany as 85±25 cN, and in the US as 2–4 oz. The US figure of 2–4 oz is just an alternative way of writing 3±1 oz, for which it is roughly equivalent (85±25 cN is 60–110 cN, and 2–4 ozf is 55.6 to 111.2 cN).

Part Style Stem Force Angle Contacts Action Comment Illumination 1973 1974 1979 1982 1985 Notes
M41-0064 Lighted straight 2½ oz. nom. 1A momentary lens lighted corner
M41-0100 Lighted straight 6 oz. 1A momentary unspecified
M41-0103 Lighted round 2½ oz. nom. 1A momentary full top lighted corner Resurrected?
M41-0104 Lighted straight 2½ oz. nom. 10° 1A momentary lens lighted corner cf. M41-0123
M41-0123 Lighted straight 2½ oz. nom. 10° 1A momentary lens lighted corner cf. M41-0104; 0° in the 1979 and 1980 price lists
M41-0125 Lighted straight 2½ oz. nom. 1A momentary lens or top lighted corner
M41-0126 Lighted straight 2½ oz. nom. 1A momentary lens or top lighted corner
M41-0127 Lighted straight 2½ oz. nom. 10° 1A momentary lens or top lighted corner
M41-0128 Lighted straight 2½ oz. nom. 10° 1A momentary lens or top lighted corner
M41-0802 Lighted round 2-4½ oz. 1A alt. action full top lighted corner
M41-0803 Lighted straight 2-4½ oz. 10° 1A alt. action lens lighted corner
M41-0822 Lighted straight 2-4½ oz. 1A alt. action lens lighted corner
M51-0106 Spacebar straight 2½-4½ oz. 1A momentary (paddle type)
M51-0107 Spacebar straight 2½-4½ oz. 10° 1A momentary (paddle type)
M51-0143 T 6 oz. nom. 1A momentary non-lighted
M51-0182 T 2½ oz. nom. 10° 1A momentary non-lighted
M51-0226 T 6 oz. nom. 10° 1A momentary non-lighted
M51-0227 Spacebar T 2½-4½ oz. 1A momentary (wire form type)
M51-0228 Spacebar T 2½-4½ oz. 10° 1A momentary (wire form type)
M51-0229 Tactile T 3 oz. nom. 1A momentary non-lighted 4 oz. nom. in the 1979 and 1980 price lists and 1986 ad.
M52-0104 straight 2½ oz. 2A momentary Possible error? Still refers to M62-0110 for 10°
M61-0025 Shift straight 2½ oz. nom. 1A momentary non-lighted
M61-0026 Shift straight 2½ oz. nom. 10° 1A momentary non-lighted
M61-0027 Shift lock straight 2½ oz. nom. 1A momentary non-lighted
M61-0028 Shift lock straight 2½ oz. nom. 10° 1A momentary non-lighted
M61-0100 straight 2½ oz. 1A momentary 1985 ad gives M61-0120 as replacing this
M61-0110 straight 2½ oz. 10° 1A momentary
M61-0120 T 2½ oz. nom. 1A momentary non-lighted 1985 ad notes that this replaces M61-0100
M61-0300 Shift straight 2½ oz. 1A momentary
M61-0310 Shift straight 2½ oz. 10° 1A momentary
M61-0500 Shift lock straight 2½ oz. 1A momentary
M61-0510 Shift lock straight 2½ oz. 10° 1A momentary
M61-0800 straight 2-4½ oz. 1A alt. action non-lighted 2½ oz. in 1973
M61-0805 straight 6 oz. nom. 1A alt. action non-lighted
M61-0806 straight 6 oz. nom. 10° 1A alt. action non-lighted
M61-0810 straight 2-4½ oz. 10° 1A alt. action non-lighted
M62-0100 straight 2-4½ oz. 2A momentary non-lighted 2½ oz. in 1973
M62-0110 straight 2½ oz. 10° 2A momentary non-lighted
M62-0900 straight 2-4½ oz. 1A-1B momentary non-lighted 2½ oz. in 1973
M71-0037 Lighted dual 2-4 oz. 1A momentary top & sides lighted centre
M71-0100 Lighted dual 2-4 oz. 1A momentary top & sides lighted centre Cherry drawing dated May 1974, last revised November 1981

See also