The lobes on the rotary cam encode the lookup table of which contacts should be open or closed in each rotational position of the shaft, which is typically rotated by a knob on the front panel of the instrument. A benefit of this design is low parasitics compared to traditional rotary wafer switches.
For cleaning, Tek recommends swiping paper soaked in isopropyl alcohol between the contacts and pads.
Ken Holland was involved with the development of cam switches at Tek.
- 040-0541-00: Cam switch repair kit (1970)
- TekScope Vol. 9 No. 1, 1977 p.14: Cam switch cleaning tips
- Media:Tek cam switch repair manual.pdf