Four-tab clone

From Deskthority wiki
Jump to: navigation, search

Four-tab clone refers to a shell design that is common to a wide variety of Alps clone switches.

Description

The majority of such switches are not branded; the only external clue as to the switch type is the mould numbering on the upper shell. The shells all follow a standard pattern, and with the mould numbering and branding removed, they would be virtually indistinguishable. The originator of this design is not known.

The lack of branding on early generations of Alps switches has led to four-tab clones being widely mistaken for genuine Alps SKCL/SKCM series and SKBL/SKBM series switches. The defining characteristic of a four-tab clone is that the shell is supported by the mounting plate from below by four small tabs; Alps themselves used two long tabs. No Alps Electric switches used the four small tabs, but some Alps clones did use long side tabs.

Four-tab clones may be referred to as Simplified Alps Type II or XM. The former is an obsolete term with an unclear meaning, which is best avoided. The latter is a misconception that all four-tab clones are from the same manufacturer, of previously unknown name; "XM" stands for Xiang Min and thus the only switches legitimately referred to as "XM" are those manufactured by Xiang Min. Simplified Alps Type IV describes a specific switch, alps.tw Type OA2.

Counterexamples

The following non-Alps switches do have the two long side tabs:

The following switches have incompatible leg spacing and are not compatible with Alps PCBs:

Uncertain

The following switches have yet to be inspected in detail:

Recognition

Mould numbering

Mould numbering examination is a first step that allows for the recognition of certain switches. In particular, NW:A## numbering appears to always indicate Taiwan Tai-Hao APC series switches. N:A## and N:## typically indicates Xiang Min's non-LED switches.

Identification of specific switches requires that the switch be opened and the internals examined; care should be taken as the contacts are fragile and supported chiefly by the upper shell, and Alps clone switches are very difficult to reassemble while still soldered into the keyboard.

Internals

alps.tw classification is by switch internals. Some of the details are quite subtle, for example how much separation there is between the fingers of two-finger switches.

Movable contact Stationary contact Leaf Mould numbering Designations
Alps.tw Type OA2 -- movable contact.svg Large Wide steel Alps alps.tw Type OA1
Alps.tw Type OA2 -- movable contact.svg Alps.tw Type OA2 (A) -- stationary contact.svg Alps.tw Type OA2 (A) -- click leaf.svg S:#A## alps.tw Type OA2 variant A
(Simplified Alps Type IV)
Alps.tw Type OA2 -- movable contact.svg Large Alps.tw Type OA2 (B) -- click leaf.svg S:## alps.tw Type OA2 variant B
Alps.tw Type OA2 -- movable contact.svg Large Wide steel Unnumbered Alps Simplified Alps Type III
One finger Alps.tw Type OA3 -- stationary contact.svg Wide steel NW:A## alps.tw Type OA3:
Tai-Hao APC series (older)
One finger Alps.tw Type T2 -- stationary contact.svg Alps clone internals -- generic PBS leaf.svg NW:A## alps.tw Type T2:
Tai-Hao APC series (newer)
Alps.tw Type T4 -- movable contact.svg Large Alps clone internals -- generic PBS leaf.svg S:#A## alps.tw Type T4
Alps.tw Type OA4 -- movable contact.svg Alps.tw Type OA4 -- stationary contact.svg Alps.tw Type OA4 -- click leaf.svg S:##
S:#A#
alps.tw Type OA4
Alps.tw Type OA4 -- movable contact.svg Alps.tw Type OA4 -- stationary contact.svg Alps clone internals -- generic PBS leaf.svg Unknown Hua-Jie AK-CN2
Alps.tw Type T1 -- movable contact.svg Alps.tw Type OA4 -- stationary contact.svg Alps clone internals -- generic PBS leaf.svg S:##
NW:#,SE:#
S:#A##
alps.tw Type T1
Xiang Min KSB-LE -- movable contact.svg Alps.tw Type OA4 -- stationary contact.svg Alps clone internals -- LED recess.svg SW:# Xiang Min KSB-LE
Alps.tw Type T1 -- movable contact.svg Alps.tw Type OA4 -- stationary contact.svg Alps clone internals -- green LED.svg S:## USw LABG01
USw LABI01 -- movable contact.svg Xiang Min KSB -- stationary contact.svg Alps clone internals -- generic PBS leaf.svg NW:##,SE:## USw LABI01
Hua-Jie AK-xN2 (2) -- movable contact.svg Hua-Jie AK-xN2 (2) -- stationary contact.svg Alps clone internals -- generic PBS leaf.svg NE:#,SW:# Hua-Jie AK-CN2 (2)
Hua-Jie AK-xN2 (2) -- movable contact.svg Hua-Jie AK-xN2 (2) -- stationary contact.svg None NE:#,SW:# Hua-Jie AK-DN2 (2)
Xiang Min KSB-C+N -- movable contact, curved crossbar.svg Xiang Min KSB -- stationary contact.svg Alps clone internals -- generic PBS leaf.svg N:A##
N:##
Xiang Min KSB-C
(alps.tw Type T3)
Xiang Min KSB-C+N -- movable contact, curved crossbar.svg Xiang Min KSB -- stationary contact.svg None N:A##
N:##
Xiang Min KSB-N
 ?  ?  ? None YH Alps clone
Two finger skinny taper Small flat metal Silver narrow leaf None YH-B Alps clone
Alps.tw Type T8 -- movable contact.svg Alps.tw Type T8 -- stationary contact.svg Alps clone internals -- generic PBS leaf.svg S:#A##
S:A##
alps.tw Type T8
 ?  ?  ? N:{Kwanda logo}-A Kwanda PB11C05

Incompatible leg spacing

At least one switch has legs spaced further apart than those of Alps switches and clones. The YH-B switch was sold as a replacement part for certain Guitar Hero controllers. It was previously referred to as the "YH-B Alps clone" before it became apparent that it is built to a revised physical specification. The images below show comparable "CS" and "YH-B" parts, very similar internally and externally, but with standard and incompatible leg spacing respectively.

The third leg in these switches appears to be present only for physical support; it is not electrically connected to anything, and can be removed if not required. The CS type can be purchased with either two or three legs.