HP Forum Archive 21

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HP-41 keyboard issue - help from the hardware gurus here Message #1 Posted by Geir Isene on 15 Apr 2012, 4:19 a.m. My HP-41CV (fullnut) turned into an HP-41CL has an issue with the minus (-) key: I need to press it rather hard for it to register. Now before I open it up and start some kind of a hit & miss adventure, I thought I'd ask the gurus of this board for a virtual hand. How exactly do I go about fixing/cleaning out this issue (baby steps please, I'm a software guy).

Re: HP-41 keyboard issue - help from the hardware gurus here Message #2 Posted by Geoff Quickfall on 15 Apr 2012, 10:03 p.m., in response to message #1 by Geir Isene Hello Geir, Take apart the calc with the usual anti static precautions. Obtain a small tube of DeOxit gold. Find the pinhole on the circuit side of the keyboard centered on the offending key. This is the centre of of the dome. Introduce a tiny amount of the deoxit into the pore on the circuit side of the dome. Exercise the key and clean up any fluid forced back out the pore during your key press exercise. Assemble and test. DeOxit works wonders. Still having a problem? Combine the DeOxit exercise with the following. Secure a stiff fine wire and introduce it through the pore. Swizzle it around and remove it. Introduce the DeOxit. Reassemble and test. Typically the key responds perfectly after the DeOxit procedure. Hope this helps. I would post a picture but I am not at home at the moment. Geoff. Go to this link: http://store.caig.com/s.nl/sc.2/category.292/.f and scroll down the page until you see the tube. If you do not have or cannot get DeOxit try the pin and some denatured alcohol. Edited: 15 Apr 2012, 10:09 p.m.

Re: HP-41 keyboard issue - help from the hardware gurus here Message #3 Posted by Geir Isene on 16 Apr 2012, 4:06 a.m., in response to message #2 by Geoff Quickfall Thanks! On that page, there is a range of small tubes of that stuff. Which one should I use (what percentage of the solution)? Or, even better; Which one of these should I buy: http://www.ebay.com/sch/?_nkw=deoxit%20gold&clk_rvr_id=332812006889 Edited: 16 Apr 2012, 4:12 a.m.

Re: HP-41 keyboard issue - help from the hardware gurus here Message #4 Posted by Geoff Quickfall on 16 Apr 2012, 6:27 a.m., in response to message #3 by Geir Isene http://www.ebay.com/itm/DeoxIT-G100L-Gold-Squeeze-Tube-100-solution-GOLD-/380429715065?pt=LH_DefaultDomain_0&hash=item589360c679 For some reason my iPad will not function the Link format. Geoff

Re: HP-41 keyboard issue - help from the hardware gurus here Message #5 Posted by Geir Isene on 16 Apr 2012, 7:47 a.m., in response to message #4 by Geoff Quickfall Thanks a whole bunch. I ordered it and will commence the surgery upon its receipt.

Re: HP-41 keyboard issue - help from the hardware gurus here Message #6 Posted by Geir Isene on 16 Apr 2012, 7:49 a.m., in response to message #2 by Geoff Quickfall A picture would also be very welcome :)

Here you go, Pictures of pores for voyager, sting, halfnut, fullnut and titan Message #7 Posted by Geoff Quickfall on 16 Apr 2012, 2:28 p.m., in response to message #6 by Geir Isene The red arrows indicate the pores, the yellow arrows the circumference (edge) of the snap domes. A. HALFNUT B. FULLNUT C. TITAN D. STING E. VOYAGER Close up of the FULLNUT Close up of the HALFNUT cheers, Geoff Edited: 16 Apr 2012, 2:33 p.m.

Re: Here you go, Pictures of pores for voyager, sting, halfnut, fullnut and titan Message #8 Posted by Geir Isene on 16 Apr 2012, 5:06 p.m., in response to message #7 by Geoff Quickfall You're Da Man.

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