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geekhack Community => Keyboards => Topic started by: Hubbert on Mon, 13 September 2010, 20:10:13

Title: How to connect to black contacts on controller (rubber dome)?
Post by: Hubbert on Mon, 13 September 2010, 20:10:13

I pulled the controller from a $5 MicroCenter "Inland" (store brand) USB keyboard, traced the keys to the black contacts on the header, verified that shorting those pins together produces the desired key, and was about to wire it to a keyswitch.

Then I find that the black contacts (which attach to the white traces on the plastic film that forms the membrane) absolutely resist soldier and cyanoacrylate (Super Glue / Krazy glue) even when I prepare with the plastic primer stick.

I also tried scraping down to the actual PCB traces, but it's easy to just scratch off all the conductor.

Can anyone explain what's going on, and give some idea of how to connect a wire to that controller board?

Here's a representative picture (different board; same issue):
http://www.craxor.com/foftar/USB-back.jpg

Title: How to connect to black contacts on controller (rubber dome)?
Post by: Hubbert on Mon, 13 September 2010, 20:19:08

Ok, thanks to that craxor site: "I used a fine sandpaper to remove the black conductive material until the copper traces were shiny then tinned them with a soldering iron."

http://www.craxor.com/foftar/

I'd still like to hear if anyone knows the official name for the material / process involved.