Datanetics DC-60 series

This article requires additional photographic illustration — need cream, latching, brown etc

Datanetics DC-60 series

Manufacturer	Datanetics
Family	DC-60
Introduced	1973
Switch type	Tactile
Sense method	Metal leaf
Rated lifetime	15M
Switch mount	Plate mount

Datanetics DC-60 series is the lower-profile, lower-cost alternative to Datanetics DC-50 series. DC-60 switches are fairly uncommon, and are best known for being used in Fluke Y1700 keyboards. In addition, they have also been used on Fluke test equipment from the era such as the high end Fluke 5440B DC calibrator. All known examples are unbranded. Unlike DC-50, this series is not known to be patented.

Construction

The two switch contacts are made from inlaid 302 stainless steel strip, sourced from Technical Materials, Inc. (now Materion Corporation).

One of the contacts is stepped, such that as the separator bar in the slider reaches the step, the contacts close suddenly and the slider is pushed downwards. This downward push from the contacts provides the tactility.

Variants

The slider colour was not specified, but it appears to be an indicator of the switch profile, with evidence suggesting low profile is brown and grey, lower profile is black, and lowest profile being white, with cream appearing to be a compromise between lower and lowest profiles not shown in the extant brochures. This remains pure speculation owing to no measurements yet existing for any encountered variants.

• Brown slider, low profile<ref name="DT_brown_cream" />
• Grey slider, low profile (below)
• Black slider, lower profile (below)
• White slider, lowest profile (below)
• Black slider, latching (appears to be lower profile)<ref name="DT_black_latching" />
• Cream slider<ref name="DT_brown_cream" /> — this might be a fraction of a millimetre lower in profile than "low" profile, but moreover, this variant has a much narrower cross which appears to be Cherry MX mount<ref name="AliExpress-cream" />

In 1975, only the standard (AKA lower) and low (AKA lowest) profiles existed. By 1981, a marginally taller ("low") profile had been introduced, along with a latching variant.

Officially, all switches are tactile, but the lowest-profile (snap-on) switch provided by Meryl Miller is inexplicably linear. His medium profile tactile switch is highly tactile, and late-issue ITT-made lowest-profile switches have been obtained with only weak tactility. It is not known if linear switches went into production; Sandy reports the Fluke Y1700's switches as linear with dust-impaired feel, which does not guarantee that his medium-profile switches do not share the same weak tactility as the contemporary lowest-profile switches.<ref name="Y1700" />

Known part numbers

Part no.	Action	Profile	Guide posts	Defined in
DC-61-01	Momentary	Lowest	Present	Datanetics 1975, ITT Datanetics 1981
DC-61-02	Momentary	Lowest	Absent	Datanetics 1975, ITT Datanetics 1981
DC-61-03	Momentary	Lower	Present	Datanetics 1975, ITT Datanetics 1981
DC-61-04	Momentary	Lower	Absent	Datanetics 1975, ITT Datanetics 1981
DC-61-05	Momentary	Low	Present	ITT Datanetics 1981
DC-61-06	Momentary	Low	Absent	ITT Datanetics 1981
DC-62-03	Latching	Lower	Present	ITT Datanetics 1981
DC-62-04	Latching	Lower	Absent	ITT Datanetics 1981
DC-62-05	Latching	Low	Present	ITT Datanetics 1981
DC-62-06	Latching	Low	Absent	ITT Datanetics 1981

Evolution

File:Datanetics DC-60 evolution.svg

The design changed with time. The heat-stakable guide posts (fixing pins) appear to have been shortened significantly at some stage, from 2.92 mm in 1975, to 1.02 mm in 1981. The 1981 brochure still depicts long guide posts and still describes them as heat-stakable, but the specifications, which match the form most commonly found, is for posts that may only be long enough to serve as fixing pins. The diagonal corners were also removed at some point, being absent from both Sandy's Fluke Y1700 examples, and from terrycherry's cream examples.

Keyboards

• HP 9825A — brown gen. 2, 1979<ref name="HP9825A" />
• Fluke 1720A Programmer Keyboard — black gen. 2, 1980<ref name="1720A" />
• Fluke Y1700 Keyboard — black gen. 3, 1990<ref name="Y1700-2" />
• Fluke 5440B DC Calibrator<ref name="5440B" />

Gallery

Overview

• 
  Three different DC-60 switches, showing three switch profiles
• 
  Assorted switches, disassembled
• 
  Assorted switches, disassembled
• 
  Switch detail
• 
  Slider detail
• 
  Unsealed switch base, showing securing pins in their initial state

Black lower profile

• 
  Switches
• 
  Keycap mount (Fluke Y1700 keycap)
• 
  Bottom
• 
  Opened
• 
  Slider
• 
  Contact separator bar in the slider
• 
  Contacts
• 
  Contacts, detail

• 
  Opened switch
• 
  Switch parts
• 
  Switch parts

Specifications

• Datanetics DC-60 brochure (1975)
• ITT Datanetics DC-50/DC-60 Key Switches brochure (1981)

Other materials

• Technical Materials, Inc. magazine advertisement from 1980

References

<references> <ref name="DT_brown_cream">Deskthority — USw LXBB03?</ref> <ref name="DT_black_latching">Deskthority — ID this keyswitch</ref> <ref name="HP9825A">Deskthority — HP 9825 keyboard restoration Posted 2014-05-05. Retrieved 2015-08-03.</ref> <ref name="Y1700-2">Flickr — Fluke Y1700 Keyboard</ref> <ref name="1720A">Deskthority — Fluke 1720A Programmer Keyboard - Switches?</ref> <ref name="AliExpress-cream">AliExpress — 5pcs/lot infrequent Keyboard switch yellow shaft …</ref> <ref name="Y1700">Sandy55 — FLUKE Y1700</ref> <ref name="5440B">EEVBlog - Repairing a 5440B/AF DC Calibrator</ref> </references>