HP Forum Archive 09

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Repairing HP41CX key Message #1 Posted by jetboy777 on 5 Sept 2002, 7:58 p.m. Can anyone advise me on repairing the "4" key on my HP41CX. It functions but has lost it's usual snap feel. Or, can someone refer my me to a previous post. Thanks.

Re: Repairing HP41CX key Message #2 Posted by David Smith on 5 Sept 2002, 8:20 p.m., in response to message #1 by jetboy777 Generally, once a key looses its snap... its all over. Nothing will get it back. The metal disk that forms the top of the key contact becomes fatigued. The key still works but the click... she be gone. The HP41 keyboard is not designed to be repairable (at least not without causing more damage to the machine than you are trying to repair). Keys that double space or do not always give an entry when pressed are easily fixed by cleaning them out with a tiny wire brush (through the plated through hole beneath each key). That said, sometimes the click problem can be caused by something spilled on the keyboard or a battery leakage problem. But this affects many keys at once.

Re: Repairing HP41CX key Message #3 Posted by Glen Kilpatrick on 5 Sept 2002, 8:42 p.m., in response to message #2 by David Smith This ain't my expertise (so what am I doing here, anyway???), I'm more of a 48-kinda-guy. But would it be possible to use "User" to _reassign_ the 4 to another key? http://www.hpmuseum.org/41cv.jpg suggests maybe [Gold] [+] would be the only easy choice (and lose the [x .LE. y?] functionality to a CATalog). Well, maybe *would it be worth it* would be a better question, but whatever, just my 0.02_$....

Re: Repairing HP41CX key Message #4 Posted by thibaut.be on 6 Sept 2002, 2:00 a.m., in response to message #3 by Glen Kilpatrick Yes, the keyboard is (almost) fully assignable, and if this could help immediately to go on using the calculator, I don't think that this is a good solution in the long term. Yes, the keybaord is almost unrepairable. Me recommandation would be to nuy a dear 41 on ebay (you sometimes find some for $30-$40) or post an ad here and switch the upper part of the calc : 5 minutes job.

Repairing HP41CX key Message #5 Posted by Emmanuel on 6 Sept 2002, 3:21 a.m., in response to message #1 by jetboy777 It's not a disaster. I thing the problem comes from a plastic pin under the key or a metal disc on the printed board. I often fixed that.

Re: Repairing HP41CX key Message #6 Posted by jetboy777 on 6 Sept 2002, 7:28 a.m., in response to message #5 by Emmanuel How do you fix it? Any pointers about removing the circuit board under the key pad. Aloha.

Repairing HP41CX key Message #7 Posted by Emmanuel on 6 Sept 2002, 5:15 p.m., in response to message #6 by jetboy777 1. Remove the 4 rubber feet 2. Unscrew the 4 screws Now you have 3 major parts: front part of HP-41, a middle "U" and the back. 3. If you have a "Fullnut", please remove the board with electronic components, the black plastic sheet, the i/o part between the previous board and the printed board. You have in front of you 48 pins. 4.Clip them all 5. Lift the printed board up You have now access to the key and/or the metal disc.

Re: Repairing HP41CX key Message #8 Posted by jetboy777 on 9 Sept 2002, 6:36 p.m., in response to message #7 by Emmanuel Yes I can do that easily. The problems is how do reattach the printed circuit board to the top half of the case. The heat swaged pins are now gone. Please any solutions.

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