HP Forum Archive 16

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HP 41CX repair Message #1 Posted by christophe stubecki on 20 Nov 2006, 11:11 p.m. Hello to all, I own a HP41cx from 1983. I did not use it from some time, and when I tried to start it again, it just did not work. It is not due to the batterie (I've changed them...), but I remember having had some issuies with the 'ON-USER' key. I had to press several times on it to start the calculator. I fear that this time it is out of order. Is there a chance that HP may repair it ? Thanks CS

Re: HP 41CX repair Message #2 Posted by Vieira, Luiz C. (Brazil) on 21 Nov 2006, 12:14 a.m., in response to message #1 by christophe stubecki Hi, Christophe; it's been some (long) time since HP no longer repairs any of the HP41-series calculators, and many other good breeds... Your only hope is to contact fixthatcalc. Anyway, just to make sure: the calculator does not turn on? Hope you succeed repairing it. Luiz (Brazil)

Re: HP 41CX repair Message #3 Posted by Hal Bitton on 21 Nov 2006, 1:26 a.m., in response to message #1 by christophe stubecki Hi Christophe, I have a 41CX with the same problem. I can usually get mine on by holding down the "ON" button for just a bit longer than normal with moderate pressure. If you don't want to risk taking your machine apart to repair it, you can turn it on without using the "ON" button by plugging in a barcode reader wand and pressing the "READ" button (located on the wand). Presto!!, your machine will come to life...just like magic...(well, almost). To turn it off, you can assign the "OFF" function to an alternate key on the user keyboard (or just let it go off by itself after 5 minutes). Best regards, Hal

Re: HP 41CX repair Message #4 Posted by Vassilis Prevelakis on 21 Nov 2006, 7:25 a.m., in response to message #1 by christophe stubecki Do you have a wand (barcode reader)? If you do, you can check to see if your 41 is working by plugging in the Wand and clicking the scan key on the Wand. This should turn the 41 on. If it does you can turn the 41 off by running the OFF command. OK its not a repair, but it'll get you round the ON problem. **vp

Re: HP 41CX repair Message #5 Posted by Bill (Smithville, NJ) on 21 Nov 2006, 8:24 a.m., in response to message #1 by christophe stubecki Hi Christophe, Have you tried a reset by holding down both the Back Arrow key and the ON key? This should hard reset the calculator and give you a "Memory Lost" message. Bill

Re: HP 41CX repair Message #6 Posted by Philip Reagan on 21 Nov 2006, 10:17 a.m., in response to message #1 by christophe stubecki It could be a cracked post inside and if so you can sometimes squeeze one of the corners together while trying to turn it on in hopes of providing enough pressure for the internal compression connector to make contact. I had success by starting with the upper left corner but this will vary by which post is cracked. If this is the case then you'll need to open the case and repair the posts.

Re: HP 41CX post repair Message #7 Posted by Randy on 21 Nov 2006, 10:36 a.m., in response to message #6 by Philip Reagan And *NEVER* use super glues (cyanoacrylates) to repair HP's. Don't do it, they don't work on plastics. The only way to repair broken posts is solvent welding liquid, it is sold in hobby stories for plastic model building. Avoid the citrus "safe/green/whatever" products, go for the ones with known carcinogens, they work, the others don't. Better living through chemistry :)

Re: HP 41CX post repair Message #8 Posted by Ron on 21 Nov 2006, 1:05 p.m., in response to message #7 by Randy I think a product called Tenax is what I've used before. It may lose its welding properties though when it gets old. It worked on my first repairs, but some time later, the same bottle didn't work for another post repair. And, I picked it up a few months later, and the bottle was empty! Where'd it go?? :^?

Re: HP 41CX post repair Message #9 Posted by Frank Boehm on 21 Nov 2006, 4:33 p.m., in response to message #8 by Ron it probably went through your lungs over time (volatile solvents tend to diffuse easily, even through firmly screwed bottles...) bad news attached: they are not great for your heatlth, that's why you always should store them in your garage etc.

Re: HP 41CX post repair Message #10 Posted by Vieira, Luiz C. (Brazil) on 21 Nov 2006, 8:01 p.m., in response to message #7 by Randy Hi Randy, guys; I am completely sure I asked this before, but as I lost another hard disk (sob!), many years of good stuff are gone. So, forgive me to ask for the n-th time: what should be the active component in such plastic weldng glue so it actually welds it? I'm in Brazil, and I am almost sure I'll find other glues with different names, so searching for the active component might lead me to an equivalent glue. Best regards and thanks again. Luiz (Brazil)

Re: HP 41CX repair Message #11 Posted by David Smith on 21 Nov 2006, 10:58 a.m., in response to message #1 by christophe stubecki It could be a dirty power switch contact. Each switch dome has a small hole under it that you can clean the swith through. You need to make a tiny wire brush out of three wire brush bristles twisted together in a pin vise, trimmed even. Place a drop of 90%+ isopropyl alcohol on the offending switch hole, dip the brush in more alcohol, and gently "scritch" around in the hole. Keep the alcohol off the display window. It leaves a white stain.

Re: HP 41CX repair Message #12 Posted by christophe stubecki on 21 Nov 2006, 1:14 p.m., in response to message #1 by christophe stubecki Thanks for all your advices, I'll try to fix it myself, and then if it still does not work, send it to fixthatcalc Best Regards, Christophe

Re: HP 41CX repair Message #13 Posted by Les Wright on 22 Nov 2006, 5:03 p.m., in response to message #12 by christophe stubecki Randy of Fixthatcalc.com does amazing work at a great price, and his resurrection of my 41CV with problems similar to yours made me very happy indeed. But keep in mind that fixthatcalc.com is basically a hobby for Randy and his wife--a very consuming and passionate one, but a hobby nonetheless. I don't think he makes any money in the process, and his waiting list to get work done is typically weeks and sometimes a couple of months. But, gosh, it is worth it. I was ready to consign my HP41CV to the recycling box, then I learned about fixthatcalc in this Forum. Including shipping I spent around $100US to get my CV back to like-new condition. Everyone in this forum can tell you that is money well spent. Good luck! Les

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