+- HP Forums (https://www.hpmuseum.org/forum)
+-- Forum: HP Calculators (and very old HP Computers) (/forum-3.html)
+--- Forum: HP Prime (/forum-5.html)
+--- Thread: Key requires a bit more force (/thread-9047.html)
Key requires a bit more force - Dave Britten - 09-11-2017 06:22 PM
I finally got a Prime, and it's working well, though I noticed that the 3 key requires a little more force. And it's not like typical key failure issues where it clicks but doesn't respond; it actually requires a firmer press to get it to click, and has no response problems once it does. Is that sort of thing common?
RE: Key requires a bit more force - Giancarlo - 09-11-2017 06:59 PM
Hello,
my Prime refers to the first hardware release (A?) and no, there is no different pressure to apply to the keys.
Which are these Keys?
Thanks
Giancarlo
RE: Key requires a bit more force - Tim Wessman - 09-11-2017 07:12 PM
(09-11-2017 06:22 PM)Dave Britten Wrote: I finally got a Prime, and it's working well, though I noticed that the 3 key requires a little more force. And it's not like typical key failure issues where it clicks but doesn't respond; it actually requires a firmer press to get it to click, and has no response problems once it does. Is that sort of thing common?
I had one like that. There was a piece of fluff in the key when I disassembled it. Maybe blast with some air?
RE: Key requires a bit more force - Dave Britten - 09-11-2017 08:25 PM
(09-11-2017 07:12 PM)Tim Wessman Wrote: I had one like that. There was a piece of fluff in the key when I disassembled it. Maybe blast with some air?
That's a good idea. I'll try that first before diving in with the screwdrivers.
RE: Key requires a bit more force - Dave Britten - 09-12-2017 02:18 PM
Ha, I fixed the problem. It was actually pretty hilarious - I've never seen this particular manufacturing "defect" before.
The air duster didn't help, so I dove in with the screwdriver. (Warranties are for wimps, right?) I didn't see anything wrong with the inside of the plastic key cap, or the outside of the keyboard dome sheet, but even just the metal dome itself felt harder to push than all the others.
I carefully started peeling up the tape layer over the keyboard domes to reach the 3. Then I had an "oh fuck" moment - I saw a key dome shoot out of the calculator and across the room.
After my heart started beating again, I examined the keyboard sheet for damage, but... all the domes were still there?
Yup, it turns out the 3 somehow had two metal domes stacked neatly underneath it! The extra, obviously not being stuck to the adhesive, happily made a run for it as I was peeling up the tape. No wonder it needed more force to depress. I dug the extra dome out of the carpet, reassembled the Prime, and now the 3 feels and responds just the same as any other key. Not sure what I should do with the extra dome, though... Tim, awfully nice of your team to hide free spare parts inside the case like that.
[attachment=5174]
RE: Key requires a bit more force - StephenG1CMZ - 09-12-2017 04:23 PM
If having two domes requires more force to depress, does that mean the calculator having no domes to depress would require less force?
RE: Key requires a bit more force - Tim Wessman - 09-12-2017 05:24 PM
(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.
![[Image: dome-arrays.jpg]](https://www.memcon.eu/wp-content/uploads/2016/10/dome-arrays.jpg)
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...
RE: Key requires a bit more force - Dave Britten - 09-12-2017 06:27 PM
(09-12-2017 05:24 PM)Tim Wessman Wrote: 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...
I have a 32S that used to have that problem (minus the bit about the water). It was a "non-working" unit listed cheap on ebay, so I took a gamble. The dome under the 1 key had collapsed, and Pioneers don't turn on fully if a key is stuck, so it appeared broken. Opened it up, made a tiny radial incision with something like an X-Acto knife, just long enough to release the tension, and now it works. That key is a little bit softer, of course, but responds fine.