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HP-41CX lock-ups - Printable Version +- HP Forums (https://archived.hpcalc.org/museumforum) +-- Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum-1.html) +--- Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum-2.html) +--- Thread: HP-41CX lock-ups (/thread-38707.html) |
HP-41CX lock-ups - Axel Poqué - 07-16-2003 I have recently acquired a HP-41CX in mint condition. It was produced in 1988 and it really appears to never have been used before (it was sold as Mint in Box). I have been experiencing several (about 5 times) lock-ups during the short time (4 days) I've used it. The calculator cannot be turned off anymore, or it shows strange characters on the display, or it just displays "MEMORY LOST" when turned on. Is this normal for a HP-41? Could this be related to just pressing a few keys to fast in succession? At least on one occasion it happened right after pressing 2 keys very rapidly when entering a program.
Axel Poqué
Re: HP-41CX lock-ups - Thibaut.be - 07-16-2003 Have you already tried fresh batteries ?
HP-41CX lock-ups - Axel Poqué - 07-16-2003 Yes, I had to, since they were the only thing not included. I would have opened the calc already, to see if maybe the srew posts were damaged, but I do not want to risk damaging it, given its good condition. There are no loose parts inside, and it feels stable in my opinion.
Re: HP-41CX lock-ups - bill platt - 07-16-2003 Axel,
HP-41CX lock-ups - Axel Poqué - 07-16-2003 It's a half-nut, produced 1988. Is there a possibility to find out IF the screw posts are cracked (maybe transportation damage?) WITHOUT opening it? (I really don't want to damage it, since it is really mint!) How stable is the case if the calc is still ok - is it possible to bend it slightly, or does it creak when you try it? (I can't try at the moment since I'm at work and the calc is at home)
Re: HP-41CX lock-ups - Harry - 07-16-2003 Both my HP 41CVs behave strange when I haven't had batteries in them for a long time (more than 2 month). One of them has a dimed display and shuts down after turning it on and off again a few times. It takes a week or so with batteries in it untill it operates propperly. The otherone sometimes does not operate at all after puting batteries in. I then have to take them out again and give it another try after a week . I got now idea what causes these strange behaviors.
Regards, HP-41CX lock-ups - Axel Poqué - 07-16-2003 Since the calc probably hasn't seen a battery for about 15 years, this could be the reason (although I guess that it has been tested by the seller). So you think the problem should go away over time?
Many thanks, Re: HP-41CX lock-ups - Thibaut.be - 07-16-2003 Yes, next step after fresh batteries is bad contact. You can easily check this out in trying to turn it on while pushing with one hand the edges of the calculator close to the 1st row keys (LN, LOG, ...). If behaviour changes and improves while your're pressing then basd contact has been recognised. If you hear something inside, it might be the fixing posts that are broken.
You will have to open it, but don't worry it's very easy.
Re: HP-41CX lock-ups - Harry - 07-16-2003 Well, I am not sure it will go away, as it sounds a bit more serious than the problems I have.
Regards, and good luck!
HP-41CX lock-ups - Axel Poqué - 07-16-2003 I think I will do this as a last resort, if the problem doesn't fix itself in time, as Harry suggested. I'll check for contact problems when I get home today.
Axel
HP-41CX lock-ups - Axel Poqué - 07-16-2003 Ok, I will do so. Thanks a lot!
Axel
Re: HP-41CX lock-ups - David Smith - 07-16-2003 My guess is the internal contacts need to be cleaned with 91% or stronger isopropyl alcohol. Halfnut machines only have the battery contact assembly. Fullnuts have a zebra strip connector under the CPU board. Both can get oxidized after a few years. One way to check for cracked case problems is to look very carefully at the side seams of the case. Gently squeeze the case halves together near the rubber feet. There should not be any movement (or mayby a few 1/1000 of an inch).
Also remove the port covers from the top of the machine and GENTLY pull on the case halves. Again there should be no movement. Dont pull too hard or you may cause the problem you are attempting to find. If the case halves come apart any then one or both of the top screw bosses has broken.
Re: HP-41CX lock-ups - Pierre Brial - 07-16-2003 Hello Axel Re: HP-41CX lock-ups - Axel Poqué - 07-16-2003 Just standard 1.5 V type N/LR-1 alkaline cells, so that should be not the problem.
I just discovered that I can provoke the behaviour by pressing the case near the top row, so it seems an internal contact problem (as suggested by Thibaut.be and Dave Smith). Re: HP-41CX lock-ups - Raymond Del Tondo - 07-16-2003 Hello, did you buy one of these NIB CX's either at ClassicCalculators.com , or alternatively, from december64 off eBay? If yes, you could try to get a replacement from the seller.
Raymond
Re: HP-41CX lock-ups - Thibaut.be - 07-17-2003 Gop ahead, open it. It's very easy, if you're a little careful you won't do any harm.
Re: HP-41CX lock-ups - Thibaut.be - 07-17-2003 BTW one can't sell a 41CX in mint condition with lose screw posts inside... You might want to try a replacement...
On the other hand once you've repaired it it will be quite invisible.
HP-41CX lock-ups - Axel Poqué - 07-17-2003 Yep, bought it NIB from december64 on eBay. It is not that there is any visible or otherwise noticable damage to the calculator, nothing loose inside, etc - it just exhibits random lockups a bit to often. If you think I could get a replacement for this...
Axel
Re: HP-41CX lock-ups - Thibaut.be - 07-17-2003 Well, try it... they still have some as far as I know, and cracked screw posts is quite strange for a new calculator.
Re: HP-41CX lock-ups - Axel Poqué - 07-21-2003 Well, John Innes (december64) has kindly agreed to send a replacement. He even offered to send me a replacement if I tried repairing it first and couldn't get it working. I declined since I didn't want to (possibly) ruin an otherwise excellent calculator. (Thanks a lot, John, I hope you don't mind me posting this here, I just wanted to give an update and praise the way you do your business.)
Axel Poqué
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