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HP Forum Archive 01

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HP 41 screw posts - broken
Message #1 Posted by John on 21 Nov 1999, 9:39 p.m.

I recently obtained a 41 CX that has the two bottom screw posts broken. Has anyone been able to fix this problem successfully. My posts are not just cracked, there are pieces of plastic broken off. I am keen to get this calc working, so any ideas would be appreciated. Thanks - John.

Re: HP 41 screw posts - broken
Message #2 Posted by Chris Catotti on 24 Nov 1999, 12:40 p.m.,
in response to message #1 by John

I don't reccommend the following, but I did it to my HP-41CV that I bought in college. It survived many things, except our newborn daughter. As she graduated from crawling to walking, she developed a keen interest in my HP-41CV. After sh dropped in one too many times, I also had cracked and destroyed posts on the bottom.

I drilled small holes from the bottom all the way through the calculator. I successfully missed any keys, and the circuit boards fared okay. Screw from the bottom small steel machine bolts all the way through. Use small washers on the bottom. I topped off the bolts with round-capped nuts. The bolt length should be sellected such that not to much protrudes through the top (to the keyboard area). Your keyboard overlays wont fit, but this will fix it for less than $2.00. I got the strangest looks from other engineers. I nicknamed the fixed 41 my "Frankenstein Calculator" for its new appearance.

Do not plan on taking it apart again, but it should work (mine did!).

Re: HP 41 screw posts - broken
Message #3 Posted by Chris Morris on 24 Nov 1999, 3:50 p.m.,
in response to message #1 by John

John, I had the exact problem also, two pieces of plastic around the screwhead bosses fell off. I used a simpler approach - just substituted two thin flat washers that gripped the bottom case; then reused the HP screws, which still had enough length to thread into the top side plastic screw holes. The upper rubber feet had to be discarded, but the case is firm. No extra holes!

Re: HP 41 screw posts - broken
Message #4 Posted by John on 24 Nov 1999, 7:26 p.m.,
in response to message #3 by Chris Morris

Not quite the same problem Chris, I have a good case back, it's my case front that has cracked an broken posts where the screws screw into. All we need to do is find a dead calc with a good case, you can have the back, and I can have the front, and both our problems will be solved !!. - Thanks, John.

Thanks to the other Chris too for his suggestion, but I think I'm going to follow Stefan Vorkoetter approach from his article, and do some soldering, that way I won't have to really care about the screw posts.

Re: HP 41 screw posts - broken
Message #5 Posted by Kevin on 25 Nov 1999, 4:17 a.m.,
in response to message #4 by John

If you'd like to try a fix without soldering or altering the way your calc looks this worked for me: 1) remove upper circuit board 2) using minute amount of quality epoxy, glue broken pieces 3) using very fine copper wire strand wrap posts 4) brush posts with epoxy to set wire wrap 5) drill upper circuitboard holes just a hair larger to fit 6) cross your fingers and put it all back together Good luck with whatever method you try.

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