HP Forum Archive 19

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HP-15C Enter Key Behaviour Message #1 Posted by Timo on 5 Feb 2010, 4:10 a.m. Hello everyone, after only reading the helpful forum topics for a while I'm now in need of a littel help as well. I recently bought a HP-15C. It is in absolutely fantastic condition, near mint. Not a scratch on the whole calculator. The keys have no backlash, i.e. they do not rattle when you shake the calc, and all the markings are perfectly intact. They all have the typical klick and feel - except the enter key. When I pressed the enter key I noticed that the displacement between the fully released and fully depressed position is only about 1/3 to 1/2 of that of all the other keys. It also does not have the same destinct keybreak the other keys have. I've read a similar description in another post here in the form, (See here) relating the enter key behaviour to the fact that it is hinged at the bottom and presses on two separate metal discs. However, the topic did not completely answer my one and only question: Is this a normal behaviour for a HP-15C enter key and if not, can this easily be fixed in any way? I'm looking forward to you replies, thanks in advance! Timo

Re: HP-15C Enter Key Behaviour Message #2 Posted by Vieira, Luiz C. (Brazil) on 5 Feb 2010, 6:33 a.m., in response to message #1 by Timo Hi, Timo; I have disassembled some Voyagers and I actually pressed the lower metal disk under the ENTER key while the calculator was turned ON, both in normal (RUN) and program mode. I do not remember observing any reaction at all, and pressing only the upper disk, the one that is actually pressed when the ENTER key acts, provides necessary action. You can see in the picture how I managed to make them work outside the case... Click to enlarge Taken from Randy´s post (link you shared): Quote: The rubber sheet between the snap discs and the keys gets holes worn through the rubber from the key pin that pushes on the snap disk. This results in keys that are lower than surrounding key. They otherwise work okay, they just don't have the correct or same physical travel as the others. This is most common on the right hand side of the keyboard, i.e. the heaviest use keys (0 and . seem to go first). I have an HP15C, bought new in the 80´s, and both [g] and [STO] keys have this problem: no keybreak (and no 'snap' feeling) the other keys have. But they work pretty fine once you press them the same way as the other keys. I sincerely would not care much about it, but this is only the way IO see it. Cheers. Luiz (Brazil) Edited: 5 Feb 2010, 6:34 a.m.

Re: HP-15C Enter Key Behaviour Message #3 Posted by Timo on 5 Feb 2010, 7:49 a.m., in response to message #2 by Vieira, Luiz C. (Brazil) Thanks for the feedback Luiz, I wasn't actually worried. As far as I can tell, the enter key is not lower than the others. And it does produce a notceable "klick" but not as destinct as the other keys. It's simply not that crisp regarding its behaviour, generally spoken. I was just wondering wether this is a general spciality of the enter key alone on the 15C? After all, it's by far the largest key on the keyboard and the only one with a slightly weird feel to it. I think it would be quite odd if it was a sign of wear since the calculator is in such a fine condition... Thanks once again and best regards! Edited: 5 Feb 2010, 7:51 a.m.

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