What are my options for repair of DEC VT100 / Hi-Tek High Profile contacts?

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MathematicalJ

03 Jun 2023, 07:21

I have a DEC VT100 keyboard with a broken switch.
Damaged Switch.jpg
Damaged Switch.jpg (362.48 KiB) Viewed 3484 times
As you can see in the photo the metal contacts are damaged, but I have the spring and plastic slider (removed in the photo). The wiki has a lot of information about this family of switches and even describes how there "were provisions made to service individual switches." But it's not clear what options exist in the present day.

Has anyone done a successful repair of this kind before?

SunshineRag_DT

04 Jun 2023, 23:47

MathematicalJ wrote:
03 Jun 2023, 07:21
I have a DEC VT100 keyboard with a broken switch.
Basically I suspect you have to find another Hi-Tek switch (they did make individual ones like below) and get (or make?) a replacement contact leaf. You *might* be able to desolder that specific switch to pull out the contacts, but you will need to wiggle it back in a little and then grab and pull the pins with the needle pliers when they poke out the back to reset them back in. Likely you will need to remove the entire switch array to replace the contacts as I suspect the PCB will be in the way.

The contacts should be pressure fit so if you can get a small needle plier with the grab bar at the end you can pull each contact out and pull from below the contact area at top to avoid mushing it flat. You of course risk destroying the contacts so try at your own risk. but you can do alot of tweaking with the contact leaf if it gets distorted to get them to work once in. You might be able to push the contact out from the bottom also to have less risk of damage. Here is a pic of one I had on hand disassembled, not same but the design should be similar....
20230604_143806 - Copy.jpg
20230604_143806 - Copy.jpg (2.89 MiB) Viewed 3417 times
I cant really be more helpful but maybe this give you some ideas, good luck!

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