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Oak Series 475



Series 475 from Oak appears to be a lower-profile derivative of the tall Series 400 switches. The newer series incorporated the following changes:

Details on Series 475 are scarce. The earliest advertisement discovered to date for Series 475 is from December 1973, in Electronic Design magazine. As with Series 400, Series 475 was produced on automated assembly line.

The Series 475 switch shell has “U. S. PAT. 3,708,635” moulded into it, indicating that it is covered by the same patent as Series 400.

The photos below are from Deepak Kandepet, and show the variant with SPST configuration and a dummy lug:

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Front view, showing the branding and patent number
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Side view, showing the revised contact design

Additional photos show that the plunger can be either dark brown (or black or grey: it is not clear) or red.


Only the following details are known:

Rated lifetime 20 million cycles

The switches are described as having crossbar-wiping, self-cleaning gold alloy contacts. The 1977 advertisement also notes that they have “Sealed PC terminations”.


The 1977 advertisement gives the following configurations:


All material was scanned by Bitsavers unless otherwise noted.