Alps SKFR/SKFS series

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Template icon--Illustration.png This article requires additional photographic illustration — internals of black variant needed
Alps SKFR/SKFS series
Alps SKFR-SKFS.jpg
Manufacturer Alps Electric
Switch type Tactile, linear
Sense method Metal leaf
Total travel 3.5 mm
Keycap mount Unique
Switch mount PCB mount

Alps SKFR/SKFS is a series of low-profile PCB-mount switches from Alps. Despite their diminutive size, they retain full 3.5 mm travel.[1]

Description

Unlike many other Alps switches, the keycap mount is not the common Alps mount.

Even though it also has four pins and is low-profile, it is neither pin-compatible or keycap compatible with the Alps SKFL switch.

The switches are branded "ALPS" on the top, in a lower weight of type than of other Alps switches.

The switches are 10.3 mm tall and include an integrated jumper.[1]

No patent has been confirmed for this switch, but US patent US4935591—filed in 1988—bears a resemblance.

Variants

A number of variants exist. Most of the part numbers are taken from the 1994 Alps catalogue, courtesy of Sandy. Part number SKFRAK has been sighted on the Web, but no details of any kind are known. A switch exists that resembles SKFR but with a taller slider that accepts regular Alps keycaps; this switch has been found only in 1995, and were this to be SKFRAK, the date may explain its omission from the 1994 catalogue.

Moniker Model Type Features Sighted
Alps SKFRAC.jpg SKFR Black SKFRAC Linear Yes
Alps SKFRAD.jpg SKFR Yellow SKFRAD Linear Short depth Yes
No photograph.svg ? SKFRAK Linear Uncertain
No photograph.svg SKFR Black LED SKFRFA Linear Red LED No
No photograph.svg SKFR Black LED SKFRFB Linear Green LED No
No photograph.svg SKFR Black LED SKFRFC Linear Amber LED No
Alps SKFSAA.jpg SKFS White SKFSAA Tactile Yes

SKFR Black

This is the linear version. An LED version exists, but this has yet to be sighted. Since there is no LED capacity in the design of SKFR Black, the LED version must take a different form.[2][3]

The following photos depict a Sager NP-925 laptop keyboard:

  • A look at the switch

  • Closeup

  • PCB layout, with four pins per switch

SKFS White

SKFS White uses an innovative design wherein a click leaf is placed in front of a chamber whose front wall is open. The stationary sides of the leaf fit into a grooves at the side of the switch, and the movable centre section backs onto the open chamber. As such, when the click leaf is released, it has nothing to strike, and produces no click sound. The result is greater tactility than if a typical tactile leaf were used, but at a cost of requiring some empty space within the switch.

NOS parts

NOS switch from AliExpress.

  • Opened

  • Tactile leaf in place

  • Tactile leaf from behind, showing that it backs against an open chamber and cannot make a click sound

  • Alternate shot of the leaf from behind under different illumination

  • Fully disassembled

Apple Adjustable Keyboard

  • Top

  • Opened, showing the contact mechanism, tactile leaf and jumper

  • Contact mechanism

  • Parts

  • Tactile leaf

  • Slider

SKFS Yellow

SKFS Yellow is a reduced-depth switch. In a 1996 example, the Alps GlidePoint Keypad took advantage of this characteristic to provide a key with an integrated LED, which suggests that possibly by 1996 the LED versions of SKFS Black, listed in the 1994 Alps catalogue, were no longer sold.

  • Top

  • Rear, showing external jumper

  • Bottom

  • Opened

Keyboards

Tall version

A nearly-identical switch exists, that has two distinct differences to SKFR:

  • The reach of the slider is greater, in a manner very similar to the robust version of Cherry ML
  • The slider accepts standard Alps mount keycaps

The series identity of this taller version is not known. Nothing matching this description was included in the 1994 Alps catalogue, but it has been found in keyboards from ca. 1991–1992 and from 1995. Alps part number SKFRAK0001 was previously listed on the Web as a surplus part without any details; neither Google nor Bing search is aware of any supplier currently listing this part.

  • Switches

  • Disassembly

  • Profile comparison with SKBM and MX

The keyboards that are known to use this switch are:

  • Datacomp DCK84/85 (1995, and ca. 1991–2)
  • Macway TP-997KB-J (case 1993, IC 1995, used for a single key)[8]

References

  1. ↑ 1.0 1.1 Geekhack — Default:ALPS switches (archive) Archived 2014-01-12. Retrieved 2015-07-22.
  2. ↑ KBtalKing — ■鍵盤史的遺跡DataComp DCK85CH61(ALPS角軸)■
  3. ↑ tttっちゃtttttったりttttったいね — Macway TP-997KB-J ALPS白軸後期
  4. ↑ KBTalking — Apple Adjustable Keyboard M1242 鍵盤拆解紀錄 Posted 2009-04-18. Retrieved 2015-07-22.
  5. ↑ Sandy — apple_adjustable
  6. ↑ MouseFan — AppleAdjustableKeyboard M1242 Retrieved 2015-07-22.
  7. ↑ Telcontar.net — Alps GlidePoint Keypad for Macintosh
  8. ↑ Telcontar.net — Macway TP-997KB-J
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