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HP Forum Archive 13

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Would someone check an HP41C halfnut, please? (and a new image)
Message #1 Posted by Vieira, Luiz C. (Brazil) on 27 May 2003, 11:44 a.m.

HI, HP41 maniacs (like me);

if there is any HP41C halfnut owner reading and with necessary skills, would you please open it and check for the hybrid LCD driver code?

I'd like to know if there are only two of these IC's - 41CV and 41CX - or if the 41C halfnut has a different one. Let me explain why.

When the first halfnuts became available, the HP41C was no longer being produced. Anyway, I read here in this very formum, that some units were released for replacement purposes. This means that the same mainboard is used for the HP41C.

As I have an HP41CV that fails to recognize more than 63 registers and the hybrid IC has the same code of another fully-operating HP41CV halfnut, I am trying to get to conclusion if this hybrid IC is defective or if there is some sort of jumper in the mainboard that would restrict the access to the remaining memory.

I compared this halfnut mainboard to another 41CV halfnut mainboard (newer) and found an additional SMD with an N2(with a slash over both characters) as identification, and it goes straight in two terminals of the hybrid chip. The other mainboard has the pads for soldering it, the one I scanned and posted here doesn't. I thought about removing it and testing it to see what sort of component it is, but I prefer waiting a bit more till I have other references. If there is a third hybrid chip for the HP41C, I will conclude this 41CV is definitely damaged.

The new, additional image is the one that shows the back image of the halfnut LCD. I forgot to add this image to the set shown in my previous post.

Thank you for any additional information.

Luiz C. Vieira - Brazil

Re: Would someone check an HP41C halfnut, please? (and a new image)
Message #2 Posted by Meindert Kuipers on 27 May 2003, 3:48 p.m.,
in response to message #1 by Vieira, Luiz C. (Brazil)

Check this out:

I have made some new pictures for my online museum, but did not have the time yet to upload it in a nice format. Put this one online just for Luis. The file is about 700+ K and a picture of my whole opened 41CX.

No Luis, I am NOT NOT NOT (excuse me for shouting) going to disassemble it any further ;)


Thank you!
Message #3 Posted by Vieira, Luiz C. (Brazil) on 27 May 2003, 8:40 p.m.,
in response to message #2 by Meindert Kuipers

Hi, Meindert;

this is what I call a great big picture!

The paper label over the hybrid chip is the same as the one found in my halfnut CX. Now I want to know if the existing HP41C halfnut have another code.

CV: 5061-7255 CX: 5061-7262 C: ??????

Thank you very much. Not a curse: if you, by any reason, need to dismantle your HP41CX, be sure there is someone that has already done something like this... and has no regrets.

Best regards.

Luiz C. Vieir - Brazil.

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