HP41 half nut internal swap??


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.


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.


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.


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)

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