HP 15C ; keys not registering


I received my 15C LE and found that 10^x and GSB keys should be pressed really hard to register. If you put normal pressure like on the other keys, nothing is registered, even if you hear a nice click. So I wonder what the cause of this problem is. How does this mechanism works and why is there this kind of issue?

Any keyboards for dummies, please? The dummy being me :)




E-mail Tim Wessman. See this thread -- archived already due to the large amount of posting that's been going on lately.


Thank you Lincoln, I already did.

I was rather looking for a technical explanation,thus to know what is causing the trouble.




Don't forget to add it to this thread.



this is or will be under investigation, if I understood correctly what Tim said. I guess someone will take a keyboard contact apart and put it under the microscope or someting like that. Maybe it's just oil & dust residue if we're lucky. Could be corrosion or some kind of misalignment also, which would be fatal.

I really hope Tim is allowed to present the results they get.



Thank you all, for your answers,

I hope there will be a solution, even for those outside the USA.

Regards from Montréal,



DISCLAIMER: You probably shouldn't take apart your 15C. We need to let HP handle this so they can work with the factory to correct the issue.

I believe the problem (in some cases) may be heat stakes not being staked down far enough. My 15C had a bad divide key, there's a heat stake right next to that and it was a bit loose on mine. Pressing the back of the PCB closer to the front of the case made the key work right while pressure was being held. I'm not 100% sure, I don't know the mechanical design of this keyboard, but if that's the cause of most of these, it would be trivial to rework.


First post.... Hello, everybody!

I bought 3 at CostCentral, two are good, and I have one with the Divide key requiring significantly more pressure. (I already reported this, and have received an e-mail back instructing me to start a case with HP tech support, which I will do shortly.) It makes starting the keyboard test a bit more interesting.... ;-)

And when I do get the keyboard test to start, I also have a key in the third row (the Two or Three key, somewhere near there...) that doesn't always "catch".

The heat stakes thing is an interesting theory, and one I think should be pursued further. I have a 32Sii you have to press down on right below the center of the the display in order to turn it on and have all the keys work, and I have seen at least one other Pioneer on TAS that was described as needing the same "lean" on it to make it work.

I'll try the "lean-on" trick with my 15C LE when I get home and see if it acts similarly.

For those keeping track (and looking for possible correlations between LE #s and Serial #s), I have:
15C LE #1: LE#02173, S/N CNA1310KC1
15C LE #2: LE#02196, S/N CNA1310KBH
15C LE #3: LE#02198, S/N CNA1310KBQ
12C 30th: #05965, S/N CNA13007NQ

I can't remember whether it's #02196 or #02198 that has the bad divide key. Gotta go home and dig them out of the boxes again to check...


The Pioneer problem of which you speak isn't a heat stake issue, it's a problem with the interconnect between the keyboard flex PCB and the CPU rigid PCB. These two circuits are held together by a piece of foam material that degrades over time, then you start having keyboard issues.

If you're feeling adventurous, this can be fixed by opening up the calculator (there's an article about that in the Articles section), removing the rigid PCB, scraping out the foam and replacing it with something else.

The 15C LE shouldn't be able to suffer from that problem, all the electronics are on one PCB except for the display, which is connected with a ribbon cable.


Do we already know the 15c LE has heat stakes? I thought I read about them having been replaced by screws ..?


The one I disassembled had heat stakes, as did the one that Katie disassembled.

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