Editing KPT switch

{{infobox dswitch
| image name        = KPT switch -- infobox.jpg
| manufacturer      = [[KPT]]
| product code      = 
| sense method      = [[Metal leaf]]
| switch type       = Clicky
| actuation force   = 
| switch mount      = [[Plate mount]]
| keycap mount      = [[Alps mount]]
| discontinued      = Unknown
| travel            = 4.2 mm
}}

'''KPT switch''' refers to several related [[Keycap mount#Alps mount|Alps mount]] switches manufactured by [[KPT]].

==Description==
KPT switches borrow the [[click leaf]] from [[Alps SKCL/SKCM series|Alps SKCM series]] switches and the [[contact arrangement]] from [[SMK vintage linear]] switches. To aid with PCB routing, the switches have three legs instead of the usual two, with the two side legs connected together. The slider is asymmetric, with a ramp on one side that operates the contact mechanism. The contact plates are held apart by the ramp, and close together when the slider is depressed. Switch travel is comparatively long at around 4.2 mm; the slider can be pressed down until it is almost flush with, or completely flush with the top of the shell.

KPT switches are [[Alps mount]], but the leg arrangement prevents them from being used in Alps keyboards.

KPT switches are taken to be those branded "KPT"; the letters are embossed on both the top and the bottom of the shell, in a fairly haphazard-looking way. These blue switches come in two varieties: a rectangular slider similar to [[SMK Alps mount]], and an Alps-style slider.

All known KPT switches are clicky.

KPT switches appear to be designed in such a way that they cannot be opened while soldered in place. The lower plate mount lugs (that sit below the plate) are part of the upper shell, meaning that the PCB would have to be removed in order to release them.

==Variants==
===Blue (rectangular slider)===
[[File:KPT-switch-blue-from-KPT-84.jpg|250px|thumb|right|Blue KPT switch with rectangular slider on a KPT-84 keyboard]]

This is the most common KPT switch. The slider is completely rectangular in cross section. There is one long lower plate mount securing lug per side.

The switch is confirmed to be not an [[Omron clone]]. The distance between the top of the [[PCB]] and the bottom of the [[plate]] should be 4.5 mm, but instead it is around 6.7 mm. Instead of 12.2 mm, the switch is 13.3 mm tall including stand-offs. With this deviation alone, replacement of all switches in a keyboard should be possible, as the PCB is not typically attached to the plate, and the leg spacing appears to be the same. However, the switch dimensions at the mounting plate are approximately 15.5 × 12.5 mm compared to the Omron expectation of 13.4 mm squared.

===Blue (Alps-style slider)===
The slider has an Alps-style cross section. There are two short lower plate mount securing lugs per side. The slider pigment is a darker, greenish shade of blue. The lower shell is effectively the same as that found in the rectangular slider version, so they should be fully interchangeable. In the [[KPT KPT-102]], they have been found used for just the top two rows of keys, although more often the KPT-102 uses only the rectangular slider version. This version of the switch is described as "vaguely Alps-like feel", while the rectangular version is described as "closer to amber Omrons";<ref name="GH-comparison" /> the cause of this observation is a mystery as the internal parts appear to be the same.

===Amber (Alps-style slider)===
The lower shell of the amber version is distinctly different. The distance from the top of the PCB to the top of the plate is reduced to 5.2 mm, which in between that of blue KPT and Omron. At around 13.2 mm, the switch is marginally shorter. The tactile point seems to be higher than with blue KPT, and stronger, suggesting that this has the operational characteristics of the blue Alps-style switch.

No keyboards have yet been discovered using the Amber version of the switch.

==Keyboards==
*[[KPT KPT-102]] (both types of KPT blue switch)
*Original [[KPT KPT-84]] and KPT-87 (blue rectangular; later keyboards used standard four-tab clones)

==Similar switches==
A number of similar switches exist, all of which so far have been found only in Far East–made keyboards from obscure marks.

*[[TEC switch]]
*[[KPT-like switch]]es

==Gallery==
<gallery widths=250 heights=187>
File:Omron vs KPT.jpg      | [[Omron B3G-S series]] white tactile vs amber and blue KPT
File:KPT amber vs blue.jpg | Amber KPT vs blue KPT, showing the different distances between PCB and plate
</gallery>

===Blue rectangular variant===
The depicted switch was harvested from an unspecified keyboard and supplied in a Mrinterface switch sample bag.

<gallery widths=250 heights=187>
File:KPT blue rectangular switch.jpg                                                    | Blue rectangular slider switch
File:KPT blue rectangular switch base.jpg                                               | Base with KPT branding and three inline legs
File:KPT blue rectangular switch side view.jpg                                          | Side view
File:KPT blue rectangular opened.jpg                                                    | Switch opened up
File:KPT blue rectangular switch with lid removed.jpg                                   | Lid removed
File:KPT blue rectangular click leaf.jpg                                                | Click leaf
File:KPT blue rectangular switch with click leaf and return spring removed.jpg          | Click leaf and return spring removed
File:KPT blue rectangular click leaf vs Alps CM white complicated click leaf, front.jpg | KPT vs Alps click leaves (front)
File:KPT blue rectangular click leaf vs Alps CM white complicated click leaf, rear.jpg  | KPT vs Alps click leaves (rear)
File:KPT blue rectangular switch contact mechanism vs SMK vintage linear.jpg            | KPT vs SMK contacts
File:KPT blue rectangular switch contact mechanism.jpg                                  | Contact mechanism
File:KPT blue rectangular switch contact mechanism 2.jpg                                | Front plate eased out
File:KPT blue rectangular switch contact mechanism 3.jpg                                | Front plate removed, rear plate eased out
File:KPT blue rectangular switch contact mechanism 4.jpg                                | Contact mechanism disassembled
File:KPT blue rectangular slider.jpg                                                    | Asymmetric slider
File:KPT blue rectangular switch shell exterior.jpg                                     | Shell exterior
File:KPT blue rectangular switch shell interior.jpg                                     | Shell interior
File:KPT blue rectangular switch components.jpg                                         | Fully disassembled
File:KPT blue rectangular switch contact mechanism front view.jpg                       | Contact mechanism (front view)
File:KPT blue rectangular switch contact mechanism rear view.jpg                        | Contact mechanism (rear view)
File:KPT blue rectangular switch contact mechanism side view.jpg                        | Contact mechanism (side view)
</gallery>

===Blue Alps-style slider variant===
<gallery widths=250 heights=187>
File:Alps.tw Type OC2 -- KPT Alps-style slider.jpg | Top
</gallery>

===Amber Alps-style slider variant===
The depicted switch is NOS obtained through AliExpress.

<gallery widths=250 heights=187>
File:KPT Alps-style amber.jpg | Top
</gallery>

==References==
<references>
<ref name="GH-comparison">geekhack — [https://geekhack.org/index.php?topic=66443.msg1597918#msg1597918 Are ALPS similar enough to Cherry MX to skip?]</ref>
</references>

[[Category:KPT switches]]
[[Category:Keyboard switches with Alps mount]]
[[Category:Clicky switches]]
[[Category:Metal contact switches]]
[[Category:List of all keyboard switches]]