Alps SKCC series

Alps SKCC series

Manufacturer	Alps Electric
Introduced	1980 or earlier
Precedes	Alps SKCL/SKCM series
Switch type	Linear
Sense method	Metal leaf
Rated lifetime	3–20 M
Bounce time	5 ms
Total travel	3.5±0.5 mm
Switch mount	Plate mount

Alps SKCC series (formerly known as Alps vintage tee mount) is the forerunner of the Alps SKCL/SKCM series, and shares the same switchplate design. The switch uses a tee mount, while keycaps use a cruciform slot. See also the virtually identical General Instrument Series S950. Production dates back to 1980 or earlier, and appears to have run to at least 1989.

Nomenclature

The series name of "SKCC" was deduced via Alps keyboard codes. The Apple III service manual was since found to cite these switches as "KCC". They remain listed here as SKCC until Alps's apparent inconsistent naming is better understood.

Description

Conventionally, the pins are to the side of the switch instead of the front/back. Some keyboards have the switches rotated by 90° with the same pin orientation as SKCL/SKCM, and at least one keyboard used mixed orientations. While the switch may appear rotationally symmetrical, and with a bit of force a cap can be pressed onto a switch in any orientation, the switch is not rotationally symmetrical. There are nubs on the sliders (the exact location of which can vary depending on the variant) that mate with indentations inside the keycap mount. Thus keyboards that have mixed orientation for their switches do not do so arbitrarily but rotate the switches to ensure that the nubs are properly aligned with the indentations inside the keycap mount. Plate mounting holes are 14 mm square.

The series dates back at least as far as 1979. Cream switches have been found in both a Radio Shack TRS-80 Model I and an Alps AKB-3420 with ICs dating from 1979, and the grey switches have been found in a Monroe calculator with ICs dating from 1979.

The switch bears the oval Alps logo on the bottom.

Specification

The specifications for the Alps AKB-3420 keyboard includes the switches, which are Alps SKCC Cream. The specification included with an older example of this keyboard from ca. 1979 gives the switch lifetime as 3×10⁶ cycles; while a later example from ca. 1988 gives a much higher rating of 2×10⁷ cycles. Bounce time is given as 5 ms in both cases, and full travel as 3.5±0.5 mm.

Evolution

The design of SKCC series changed with time. Manufacturing lifetime appears to have had a substantial overlap with Alps SKCL/SKCM series: SKCC has been found with black, grey, tall white and short white switchplates. This implies that SKCC series was still in production in 1989.

• 

  Side-Angled Cream with black switchplate and terminal sealant

• 

  Tall Cream with grey switchplate (1987 batch)

• 

  Cream with short white switchplate; the redundant switchplate ridge is clearly visible

Changes include:

• Addition of a chamfer to either side at the bottom; this appears to be a very early change
• The exterior recess in the base enclosing the terminals has had both straight and semicircular ends, as well being unbroken and later divided
• Some batches used terminal sealant, of a red or translucent orange colour, which appears to be one reason for the recess in the base
• Newer revisions featured a ridge in the base to hold the switchplate; this was retained after the change to short switchplates, when the switchplate no longer reached down to the bottom of the switch

Disassembly

The side tabs are much harder to unlatch than SKCL/SKCM series, and noticeably thinner, and consequently face a much greater risk of snapping clean off when trying to lever them open. When opening a switch, it helps to insert a thin object underneath the tab on one side, prior to opening the tab on the other side, to stop the tab on the other side from closing again. The cocktail stick method used with Alps SKCL/SKCM series is not possible with SKCC, as the ledge that rests on the mounting plate overhangs the tabs.

• 

  Fragile side tabs

• 

  Opening a switch

Variants

Few part numbers have been recovered. To date, there is tentative evidence to suggest that subseries "A" comprises the tall momentary switches, and subseries "B" comprises the standard height momentary switches. More data is required to confirm this theory.

The height of the black and grey variants have not been measured, and are unclear.

Slider and keystem height measurements are approximate and averaged from multiple switches, rather than being taken from any specifications. The keystem height is measured from the circular base through which it protrudes to the top of the slider. The keystem height is measured in the axis relative to the keycap, not to the slider motion (only different for side-angled cream).

	Name	Model	Type	Weight	Slider height	Keystem height
	Alps SKCC Brown		Momentary
	Alps SKCC Grey		Momentary		ca. 9 mm	ca. 4 mm
	Alps SKCC Tall Black		Momentary
	Alps SKCC Cream	SKCCBJ	Momentary	70 gf	9.7 mm	5.0–5.3 mm
	Alps SKCC Green	SKCCBK	Momentary	~60 gf	9.7 mm	5.1 mm
	Alps SKCC Tall Cream	SKCCAF	Momentary	70 gf	13.4 mm	4.7 mm
	Alps SKCC Lock		Alternate action		9.6 mm	5.1 mm
	Alps SKCC Cream LED		Momentary illuminated	70 gf?
	Alps SKCC Side-Angled Cream		Momentary		13.0 mm	5.5 mm

Unmapped part numbers

The following part numbers are known to exist (surplus stock no longer available), but no photograph exists of them and they have not been assigned to a moniker above:

• SKCCAC