SMK Alps mount lock

SMK Alps mount lock

Manufacturer	SMK
Family	SMK second generation
Switch type	Alternate action
Sense method	Metal leaf
Total travel	3.5 mm
Keycap mount	Alps mount
Switch mount	Plate mount

SMK Alps mount lock is the alternate action switch in the SMK second generation series.

Description

The operation is very similar to that of SMK lock, where a swivelling pin follows a track. Where the J-M0404 series version used an external module to house the pin and a track on the slider, the second generation design reverses this: the track is in a separate block, and the pin fits into the slider. The position of the track block inside the switch explains why the left-hand retention clip is offset to the back of the switch.

The pressure spring that supports the follower pin is small, at 4 mm long and 1.38 mm in diameter; this is larger than the equivalent spring in RAFI full-travel key switch, which in RS 74 M is a mere 2.7 mm long.

Keyboards

• Some Apple Keyboard II
• Some Apple Desktop Bus Keyboard

Gallery

• 
  Top; the mini PCB from the Keyboard II is still attached
• 
  Opened
• 
  Switch contacts; note that they are inverted as this switch needed repair
• 
  Follower pin, released
• 
  Follower pin, pressed in
• 
  Follower pin removed from the slider
• 
  Latch track block
• 
  Pressure spring length
• 
  Pressure spring diameter
• 
  Switch components