deskthority

I posted about my Fluke 1720A Programmer keyboard with scratchy Datanetics DC-60 Switches. I like the board but the scratchy switches are annoying so I wanted to see if I could disassemble and clean the switches AND get them back together in good working order. It did not appear likely to be an easy task.
The switches are held together with two plastic rivets that have had the ends "mushroomed" to hold them in place and this prevents simply prying the switch apart.

Using a Dremel on a stand with a 3/32" bit I removed just the very end of the rivets
After this it is possible to pry the switch open leaving the majority of the rivets intact for re-closing the switch.
As others have previously noted the contacts are very similar to Hi-Tek or Stackpole. There is a bar in the slider that holds the contacts apart until the switch is depressed.
The riskiest part is reassembly - great care has to be taken to gently slide the bar between the contacts without bending them!
If care is taken not to remove more than the tips of the rivets (only a millimeter or two) the rivets will snap back into place and I have found the switches to be held together firmly. They could be glued, of course, but I wanted to be able to open them again if necessary.

I cleaned all the switch parts in 91% isopropanol and they are now much smoother and no longer scratchy. I did put some Superlube along the outside of the slider on one switch, but I don't really feel much difference between the lubed switch and the other newly cleaned ones - I guess it could make a difference down the road though.

Of course another issue is that desoldering, opening, cleaning and reassembling every switch on the board is quite a task. I think I'm going to just gradually work at it as time allows.

Impressive work once again, these pictures are better than what we have on file in our wiki page. Will you allow us to use your pictures for our wiki page please?

wiki/Datanetics_DC-60_series

seebart wrote: Will you allow us to use your pictures for our wiki page please?

wiki/Datanetics_DC-60_series

Thanks. For sure, if any of the pics would be of use, more than welcome to them. I can take additional pictures (hopefully with a better camera) if here are any in particular that would be helpful. I'm going to have to read up on the wiki how to page - there I have been wanting to try adding a little, but have been a little afraid of screwing up the formatting or something on a page.

Looking at a unused parts, it did seem like the shell snapped together, but in your case, the parts that would secure the shell seem to have been drilled away. And yet, somehow it still snaps together.

Daniel Beardsmore wrote: Looking at a unused parts, it did seem like the shell snapped together, but in your case, the parts that would secure the shell seem to have been drilled away. And yet, somehow it still snaps together.

What appears to be happening is that by drilling away just the very tip of the rivets, enough of the "mushroom" is removed to allow the switch to be opened without snapping the remaining rivet, but enough is left so that the switch will snap back together.
The six switches I've done so far stay together firmly, but can be pulled apart again without difficulty. Trying to pull a keycap, for example, would definitely lift the top off the case but they won't just pop open on their own. Applying some glue to the rivets would leave them very tightly closed again, but I'm going to leave mine unglued for now because I want to be able to open them at will.

It's a very distinct ridge when new:



I don't know how strongly that holds as I only have one set of new parts and I can't risk assembling it!