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HP41 half nut internal swap?? - Printable Version

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HP41 half nut internal swap?? - Dia C. Tran - 10-04-2004

I just got a 41CV in excellent condition and I have a 41CX blank nut for a long time. Both are of the halfnut version. I wonder if I can swap the guts of the 2 calculators so that I would have a CX with the labeled keyboard?
I know that the CX blank nut is quite rare and valuable but it's a pain to use it and I do want the extra CX functions.

Re: HP41 half nut internal swap?? - Vieira, Luiz C. (Brazil) - 10-04-2004

Hi, Chan Tran;

As I have changed "guts" between halfnuts and fullnuts, I can tell you it is possible. You'll have to cut ALL plastic rivets in both units and change the mainboard (it's a keyboard/mainboard/display driver in one piece). Then you'll have to fix both units back, using one of the techniques already mentioned here.

If you want to keep the blanknut "layer", I see no other solution. BUT... if you are not willing to keep it, maybe you can trade your CX blank nut for a conventional CX halfnut and have some money back, if applicable. Rememember that many CX in a box were found last year and sold as new units. If you believe it's a good deal, a "fresh new" CX might be a good solution as well, and you'd keep both CV and CX (plus the blank nut) untouched.

If you still need to change their guts, I have some images with the location of the rivets. To be honest, I'd not disassemble a working 41... It's a pain to dismantle it and join the pieces back together. I've done it a few times, and the units actually needed service. Otherwise, I'd not do that. My opinion, of course. (and I apologize posting it here because I was not asked to...)


Luiz (Brazil)

Edited: 4 Oct 2004, 9:59 a.m.

Re: HP41 half nut internal swap?? - Dia C. Tran - 10-04-2004

Thank Luiz,
It seems to me much more involved that I imagined so I think I won't do it as both of them are in excellent condition and I know it's hard not so damage them just a bit. As for buying a regular CX, I don't think I will do that as they are very expensive and I don't believe in that. I paid over $300 for the 41C it was introduced and also $300 for a CV to replaced it a couple of years later after the 41C was stolen. However, I don't want to pay big bucks for them now. I bought 6 CX blanknuts in brand new condition for $5 each in 93. I have given 5 of them away as gifts. I just bought another like new CV for 50 cents at an estate sale.

Re: HP41 half nut internal swap?? - Vieira, Luiz C. (Brazil) - 10-04-2004

You lucky guy...

Keep them all and, as it happens that you have another golden chance like these ones, please, let us know... Five blank nuts for $5 each... Wow! I'm not a collector, I keep with me all calculators I know I'll use somehow, so I cannot think of what to do with a blanknut. BUT if it is an HP41CX... That's another story.


Luiz (Brazil)