Key requires a bit more force

[Tim Wessman]

(09-12-2017 02:18 PM)Dave Britten Wrote:  Ha, I fixed the problem. It was actually pretty hilarious - I've never seen this particular manufacturing "defect" before.

Glad you figured it out! It is actually a very rare defect. Domes come on a big sheet and generally are stuck with another layer (tape layer as you call it) and removed from that sheet. That layer then is generally stuck to the PCB. Occasionally though, the origin sheet gets two domes on it. I believe that is actually a spec they call out along with depression force, travel, etc.

Here's an image from a company that makes that sort of thing.



Provided you were careful and everything stuck back, I would not anticipate ever having issues.

The more common (but still quite rare) issue is a "collapsed" dome where the dome loses integrity and a crushing wave of deep ocean water rushes in to..... wait. That was a movie I watched...