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[top]Introduction


There are two main types of Cherry mechanical keyboard switch known as MX and ML. Of MX type there are different varieties and these can be identified by stem colour. Partial part numbers and operating forces are included for reference.

In addition to MX and ML switches, there are the MY mechanics-over-membrane modules.

[top]MX

US Patent 4467160
Datasheet: Current-- 1998-- Old-- Red
Overview of the connections between key feel and stem color: "Click Tactile" is Blue. "Soft Tactile" is Clear. "Linear" is Black and Red. "Ergonomic" is Brown.

Cherry MX switches are the most common type of Cherry keyboard switch discussed at Geekhack and are 4mm travel, rated at 50 or 20 million operations. The G80 range of Cherry keyboards have MX switches. Some Cherry Corp POS keyboards also use them. MX switches can be ordered with either a wire bridge, a diode (for NKRO boards) or red/green/blue LEDs (mainly for Caps Lock / Num Lock / Scroll Lock indicators with keycaps having a transparent section) installed in an auxiliary position.

Cherry MX switches are held together by 4 tabs that are accessed at the bottom of the switch. The parts include a base, a spring, and different colored stems.


They share a common base. The actual electrical contact is a gold/silver alloy as seen in the middle of the switch. You can also see the slight dabs of clear grease on either side. If you clean the switch with solvents you may find the switch to be grainier as a result.


You can see the actual electrical legs in a diagonal pattern at the top. At the bottom are two holes where a jumper, diode, or LED can be inserted.


These are the official Cherry MX specifications
Quote:
Electrical
Voltage: 12 VAC/DC max.
2 VDC min.
Current: 10mA AC/DC max.
10�A DC min.
Insulation Resistance: 100M at 100V
Initial Contact Resistance: 200m (25m typical)
Bounce Time: 5msec (at 16 in/sec. actuation speed)
Capacitance: <2pF (at 1kHz)
Operating Temperature: -10�C to +70�C
Storage Temperature: -40�C to +70�C
Flammability Rating: UL94HB
Materials
Case: Thermoplastic
Contacts: Silver-Gold?? (AuAg 10)
Spring: Stainless Steel
Solderability: Wave solder, 5 seconds at 500�F

[top]Regular key types

  • Black: linear, Actuation Force 60cN, MX1A-1 (Cherry G80-11900, Deck 82 and Legend, DSI SMK-88, Steelseries 7G/6Gv2, TG3 BLT aka Data911 MDS2000)

  • Blue: click, Actuation Force 50cN, MX1A-E (Filco Majestouch, DAS Keyboard III, DSI Modular Mac, Ione Scorpius M10, NTC KB-6252CH. Evidence suggests that Dolch PAC network analyzers all have Cherry blue, but the sample size is under a dozen verified units.)

    The Cherry Blue switch has a "Mexican Jumping Bean" type mechanism to generate the click as seen in this QWERTER's clinic Flash Animation.

  • Brown: soft tactile (ergonomic), Actuation Force 45cN, MX1A-G. Some asian websites refer to this as the "Tea Axis" Cherry switch.

  • Clear: soft tactile, Actuation Force 55cN, MX1A-C (although these LOOK white technically they are referred to a Clear according to Cherry Corp to distinguish them from the White MX switches)
    Quote:
    C Momentary, single pole, tactile feel, 2.3 oz, clear keystem

  • Red: linear, Actuation Force 45cN, MX1A-L (Cherry G80-3494, Cherry G80-3600LYC)




[top]Space bar types

  • Green: click, Actuation Force 65cN, used for space bar in Cherry keyboards with blues, MX1A-F
  • Light Grey (grey 39): tactile, Actuation Force 80cN, used for space bar in Cherry keyboards with clears and browns, MX1A-D (Compaq MX 11800), G80-8955HPDUS (POS)
  • Dark Grey (grey 37): linear, Actuation Force 80cN, used for space bar in Cherry keyboards with blacks, MX1A-2


[top]Misc

  • Black with grey upper housing: alternate action, 60cN, MX1A-3
    This switch appears to act like the ALPS capslock switch, as it incorporates a latching mechanism. Toggles state each time it's pressed (aka push-on, push-off). Link to more pictures here.

  • Grey: tactile, Actuation Force 105cN, used for space bar, MX1A-B *
  • Orange: linear (NCR F020)
  • White: click. This is a rare older switch. Link to Sandy55's description and pictures.
  • White: tactile, 80cN, MX1A-A. (information source )
    - must be rare since Sandy55 has not seen this switch.
    From the old Cherry MX Datasheet:
    Quote:
    MX1A-Momentary single Pole with Tacticle Feel, 80cN Standard, Movement Differential, white keystem

[top]Internals


Additional pictures of the most common types of MX switches disassembled:
http://park16.wakwak.com/~ex4/kb/tech_cherry_mx.htm
Some more...
http://bbs.kbc-china.com/thread-2571-1-1.html

[top]Reliability


As of 1998, black switches were rated at 50 million operations, while the tactile blue and clear types had a 20 million operations rating. In more recent times this was revised to 50 million for all types.

It be noted, however, that the tactile types are more easily disturbed by debris that finds its way into the switch. This is usually the cause when blues lose their click; some compressed air tends to remedy the problem.

[top]About copies


A copy of the MX click switch exists. It can be identified by the lack of Cherry logo and cutaway for LED on upper housing. It is known to some as "Taiwan's white axis". Here is an auto-translated article about this switch: http://translate.google.com/translat...iteswitch.html A black stem variation also exists.
  • Black: click (Macally ADB numpad)
  • White (translucent): click (Qtronix KT-305, Ione / Qtronix Scorpius 32 / Qtronix Scorpius 305)
  • Yellow: ?

[top]Part numbers


The Cherry part numbers for MX switches are made up of 'MX' plus six characters indicating variations, in the format "MXab-cdef".
This information has been collated from the various Cherry datasheets.
Any text that is not a straight copy from any datasheet is surrounded by curly brackets e.g. {click}.
These tables list the options for each character:

a = Contact Material
  • 1: AuAg10 10mA/12V max
  • 2: �
  • 3: �
  • 4: �
  • 5: Special

b = Contact Config.
  • A: SPSTNO
  • B: �
  • C: Special
  • D: �

c = Operating Characteristics, Actuating Force and Key Style
  • 0: Special
  • 1: Momentary, single pole, {linear}, 2.1 oz / 60cN, standard, black keystem
  • 2: Momentary, single pole, {linear}, 2.8 oz / 80cN, spacebar, {dark} grey 37 keystem
  • 3: Alternate action, single pole, 2.1 oz / 60cN, {grey upper housing, black keystem}
  • 4:
  • A: Momentary single pole with tactile feel, 80cN standard, {click} Movement differential, white keystem {obsolete}
  • B: Momentary single pole with tactile feel, 105cN space bar, {click} Movement differential, grey 36 keystem {obsolete}
  • C: Momentary, single pole, tactile feel, 2.3 oz / 65cN, clear keystem
  • D: Momentary, single pole, tactile feel, 2.8 oz / 80cN, spacebar, {light} grey 39 keystem
  • E: Momentary single pole, tactile feel 2.1 oz / 60cN, �click� differential movement, blue keystem
  • F: Momentary, single pole, tactile feel, 2.8 oz / 80cN, �click� differential movement, space bar, green keystem
  • G: Momentary single pole with tactile feel (ergonomic), 55cN standard, brown keystem {special order only?}
  • L: {Momentary, single pole, linear, 45cN, standard, red keystem} {special order only?}

d = Keystem Configuration
  • 1: Std straight for cylin & std keycaps

e = LED Diode
  • N: No LED, No diode
  • R: Red LED, no diode
  • G: Green LED, no diode
  • Y: Yellow LED, with diode
  • D: No LED, with diode
  • J: with jumper wire, no LED, no diode

f = PCB Mounting Pins
  • N: No pins (metal frame req)
  • W: With pins


Examples of part numbers for currently available switches

Blacks:
  • MX1A-11NW = no jumper or diode, PCB mounting
  • MX1A-11NN = no jumper or diode, faceplate mounting
  • MX1A-11JW = with jumper, PCB mounting

Blues:
  • MX1A-E1NN = no jumper or diode, faceplate mounting
  • MX1A-E1JW = with jumper, PCB mounting
  • MX1A-E1DW = with diode, PCB mounting

Clears:
  • MX1A-C1JW = with jumper, PCB mounting

Browns:
  • MX1A-G1DW = with diode, PCB mounting

[top]Buying


The Cherry part numbers are:

PCB mount (stabilizing pins at bottom):
  • Black: MX1A-11NW
  • Blue: MX1A-E1NW
  • Clear: MX1A-C1NW

Faceplate mount (no plastic pins at bottom)
  • Black: MX1A-11NN
  • Blue: MX1A-E1NN
  • Clear: MX1A-C1NN

They are available from Mouser or from DigiKey or in the UK Newark. Unfortunately Cherry Brown Switches (Cherry part number MX1A-G1NW) do not appear to be available except by special order. More places where you can buy Cherry Swiches are listed in the Stocklists Of Cherry Switches Wiki. They're about $1 each, with about $2 for USPS first class mail (there are a ton of shipping options).

[top]ML


US Patent 5488213
Datasheet: Current-- 1998

ML type is a low profile switch with 3mm travel, rated at 20 million operations with an operating force of 45cN. The G84 range of Cherry keyboards have ML switches. There are some pictures of the switch disassembled here: http://park16.wakwak.com/~ex4/kb/tech_cherry_ml.htm

Cherry ML-4100, G84-4100, G84-4400, G84-4700
Datacomp DFK65U
Filco FKB-65EU-MM

[top]MY



In addition to MX and ML there are the MY mechanics-over-membrane modules ("FTSC technology") in the G81 range of Cherry keyboards. These are based around a leaf spring over membrane switch design (with an additional helical spring which contributes most of the force) and are felt by many to be stiff, probably due to the force quickly rising with travel.



More pictures of the MY switch (US patent 4800245) can be seen here:
http://www7.ocn.ne.jp/~hisao/image/g81hbu.htm
MY force displacement diagram as of 1991
Early black stem type

[top]Older Cherry keyboard switches


An earlier version of MX type can be seen here:
http://sandy55.fc2web.com/keyboard/old_cherry_mx.html

There are two other types of Cherry keyboard switch known as M81 and M84. These are super low profile with 2.54mm travel and operating force of 2.5oz (approximately 70cN). Both M81 and M84 are available in linear or tactile feel. Datasheets can be found here: http://www.greendich.com.tw/products/cherry/switch.htm

The EPSON HC-20 (or HX-20) has a variant of the M81/M84 switch:
http://www7.ocn.ne.jp/~hisao/image/hc20.htm


[top]Keyboard Model Numbering


For more details about the Cherry "Model numbers", check the Dating Cherry Keyboards wiki.


[top]Mods


It is possible to swap stems and springs in Cherry MX switches. The bottom casing including the switch and the top casing are identical on all switches.

The Cherry Brown and Cherry Blue Springs are identical:


Interesting combinations:
  • Brown or Blue spring + Black stem = Very close, if not identical, to a Red switch. (Nickname: 'Ghetto Red').
  • Black spring + Brown stem = A higher force brown, but the tactile bump appears to lessen.
  • Black spring + Blue stem = Similar to a Green spacebar switch (which is similar to the obsolete White clicky switch, by the numbers).

In other words, you can emulate a Cherry Red by swapping a Black Stem into a Cherry Brown (or Blue) Switch. Or you can pull a spring from a Cherry Brown or Cherry Blue and put into a Cherry Black switch with the same result. (Technically since nobody has posted a high rez picture of the red stem the slope of the tactile prong may be slightly different).

Cherry MX switches can be disassembled without desoldering if they are PCB mounted. If they are mounted on a Metal Plate and a PCB underneath they will have to be desoldered.


Switch Swapping by soldering/desoldering: Kinesis Keypad as an example and detailed pics
Opening up PCB Mounted MX Switches: Tool 1, Tin Can
Opening up PCB Mounted MX Switches: Tool 2, ForkOdeath
MX Stem/Spring Swapping - quick impressions
Switch silencing - Dental Band method with sound samples, O-ring method


Contributors: Chloe, ricercar, meltie, ripster, fastbuck, Mental Hobbit, acevery, Soarer, British, Ekaros, Infinite north
Created by Chloe, 26 January 2009 at 04:33
Last edited by ripster, 2 Weeks Ago at 19:58
Last comment by ripster on 19 October 2010 at 01:06
84 Comments, 20,901 Views

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