HP Forum Archive 20

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15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #1 Posted by Tim Wessman on 30 Sept 2011, 12:07 p.m. Hello, The support team now has received enough units to analyze. They now ask that if you have an issue, please go through the normal support process. Thank you to those that contacted me and sent back units! TW -- Although I work for the HP calculator group, the thoughts and comments expressed on this forum are my own. Edited: 30 Sept 2011, 12:18 p.m.

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #2 Posted by Pal G. on 30 Sept 2011, 12:33 p.m., in response to message #1 by Tim Wessman Thanks, Tim and HP, for immediately addressing the keyboard issue - even with the HHC2011 event occurring during the HP 15C LE roll out.

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #3 Posted by Reth on 1 Oct 2011, 7:00 a.m., in response to message #2 by Pal G. And what exactly was addressed? I thought contacting support people was the only option anyway and nothing has been added. I see no official confirmation/admittance that the keyboard has issues. Wouldn't be better if the support team disclosed their findings? With 12% failure rating I think HP should be a lot more specific about the problem.

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #4 Posted by Lincoln R. on 1 Oct 2011, 10:36 a.m., in response to message #3 by Reth Quote: The support team now has received enough units to analyze. Tim said they had enough units to analyze, not that they were done analyzing them. While this may seem like a "simple" problem, nothing is simple in industry. They'll probably have to disassemble a bunch of calculators, try to figure out why the keyboards don't work, figure out how to correct that, and then deal with the factory to make sure future units don't have this problem. I think I have a pretty good idea of what the issue is, but I'm not a mechanical engineer, nor do I know anything about HP's keyboard design so what I noticed could just be a coincidence or one isolated case.

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #5 Posted by Reth on 1 Oct 2011, 11:18 a.m., in response to message #4 by Lincoln R. Yea, I know what Tim said, I was wandering why the excitement, just because some people did their job? Quote: I think I have a pretty good idea of what the issue is, but I'm not a mechanical engineer, Would you speculate on this a bit?

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #6 Posted by Lincoln R. on 1 Oct 2011, 11:27 a.m., in response to message #5 by Reth I had a 15C with a bad divide key. It clicked, but didn't register unless you pushed it hard. I decided to open the back since they're not too hard to disassemble and discovered that if you held the PCB and the front case together, the key worked fine. Closer examination seemed to show that the heat stake closest to that key wasn't melted down far enough.

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #7 Posted by Reth on 1 Oct 2011, 12:05 p.m., in response to message #6 by Lincoln R. That's interesting, thanks for sharing. But is there such a heat stake close to the "." key (my case) and could you fix the problem yourself? Cheers,

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #8 Posted by Lincoln R. on 1 Oct 2011, 12:28 p.m., in response to message #7 by Reth Unfortunately I do not remember. It could be possible to carefully remelt the heat stake yourself, but I really wouldn't recommend it on something this new under warranty and with a known defect.

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #9 Posted by Reth on 1 Oct 2011, 12:50 p.m., in response to message #8 by Lincoln R. Me too, thanks.

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #10 Posted by robert rozee on 1 Oct 2011, 12:55 p.m., in response to message #8 by Lincoln R. the trick would probably be to make up a jig to hold down the PCB firmly, then place a drop of 2-part 24hr epoxy resin glue over the faulty stake, such that it would run down and around, and fill in the gap. BTW, has anyone got photos of a disassembled 2xCR2032 HP-12C showing the actual keyboard construction/design. had a bit of a look with google, found various comments from 'experts' but no actual photos.

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #11 Posted by uhmgawa on 3 Oct 2011, 12:56 a.m., in response to message #10 by robert rozee Quote: the trick would probably be to make up a jig to hold down the PCB firmly, then place a drop of 2-part 24hr epoxy resin glue over the faulty stake, such that it would run down and around, and fill in the gap. Heat stakes are no one's friend and are mainly a concession to cost reduced assembly. A malformed stake might just be a sign from above to rid the calc of them altogether and secure the pcb to the housing with screws. Doing so results in a serviceable keyboard and more flexibility in modifying the pcb. Assuming the 15c le stakes voids are identical to the 12c+, an M1.2 screw is about the correct size to self thread the core. For a 12c+ stake cut flush with the pcb surface the resulting core void depth is about 4.5mm IIRC. Add to that the thickness of a plastic washer and a 4~5mm screw length should work. Appropriate screws are available as a service item for cell phone, etc.. repair (try Evilbay). Washers are easier to make than find and can be cut out of plastic stock with a paper punch.

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #12 Posted by Katie Wasserman on 3 Oct 2011, 2:41 a.m., in response to message #11 by uhmgawa Have you modified your 12C+ as you describe, replacing the heat stakes with screws? If so, did you have any problem with cracked cores?

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #13 Posted by uhmgawa on 3 Oct 2011, 3:10 a.m., in response to message #12 by Katie Wasserman Quote: Have you modified your 12C+ as you describe, replacing the heat stakes with screws? If so, did you have any problem with cracked cores? Not yet as I'm still waiting on the M1.2 screws. I thought to grind a parallel slot partially through the threads of a single screw and use it as a poor-man's tap to thread each stake in advance. Although I suspect that is overkill. Concerning the potential to crack a stake, I'd actually thought to slice through the stakes with a very thin kerf saw such that the screw when driven would freely expand the stake until it wedged in the pcb hole. That as well seems excessive. M1.2 is almost a little undersize and I'm wondering if there will be sufficient mating wall depth to thread. M1.3 is probably ideal but there isn't much of an economical choice with this microscopic hardware. If there is general interest I'd be happy to report the results.

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #14 Posted by Marcus von Cube, Germany on 3 Oct 2011, 3:26 a.m., in response to message #13 by uhmgawa Maybe heating the screw is an option?

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #15 Posted by uhmgawa on 3 Oct 2011, 9:05 a.m., in response to message #14 by Marcus von Cube, Germany Quote: Maybe heating the screw is an option? Mounting a jeweler's cross bit in a temperature controlled iron had crossed my mind. However I've had mixed results in the past trying to so. Eg, controlling both iron temperature and heat transfer to the screw such that the plastic isn't overheated. In this case the stakes are a low, fairly isolated mass and if they should overheat and distort it could make for a really bad day. The other potential is to have the ABS reflow so well it seizes the screw in the stake with similar consequences. Although one scenario where this may be worth a shot would be if the screw threads should strip out of the stake from repeated insertions/withdraw cycles. Touching an iron to the head of the screw in cautious doses can reflow the sheared ABS sufficiently to reestablish functional threads. This may be useful in my case as I'm concerned M1.2 diameter may be undersize.

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #16 Posted by uhmgawa on 3 Oct 2011, 6:46 p.m., in response to message #12 by Katie Wasserman Quote: Have you modified your 12C+ as you describe, replacing the heat stakes with screws? If so, did you have any problem with cracked cores? I came across some jpegs I took a while back of 12c+ internals. Unsure whether others here have already done so but on the chance they may be useful to someone I've located them here. No 15c le pictures yet but the current lqfp package makes a compelling case for pcb trace out and capture of the schematic. I don't expect anything surprising as it appears to be functionally identical to the 12c+ which AFAICT is largely the Atmel reference design. However it would be a useful reference for a plethora of lost time projects. Maybe after the "limited" marketing campaign is over and the "recoup the NRE" phase begins I'll pick up a second 15c le from my local MalWart.

Re: 15C Keyboard Issues [UPDATE- DO NOT EMAIL ME] Message #17 Posted by uhmgawa on 3 Oct 2011, 6:55 p.m., in response to message #10 by robert rozee Quote: BTW, has anyone got photos of a disassembled 2xCR2032 HP-12C showing the actual keyboard construction/design. had a bit of a look with google, found various comments from 'experts' but no actual photos. I just uploaded some -- see above post in this thread. Note the choice of legged snap dome was functional as the dome-side pcb routing takes advantage of this. So if you'd like to get the tactile feel of a legacy voyager you could cover the center contact trace exit with a strip of kapton tape and substitute a full circular dome. The original voyager domes are 9mm with a 150~170g actuation force. I forget what I'd measured the 4 legged domes on the 12c+ (and presumably 15c le) to be, but I'll recheck. Added: The 4 legged domes in the 12c specimen I have at hand are 8.36mm in diameter with an approximate 220g inflection force. Assuming this is representative of average production, the force needed to actuate a 12c dome is substantially greater than legacy voyager counterparts. Cut/legged domes also have a sharper transition compared to the full domes of the same diameter, which is likely the cause of the tactile difference. Edited: 4 Oct 2011, 11:25 a.m.

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