Opening HP41 modules?

[emece67]

Hi all,

The sort version of this post: does anybody know how to open/dismantle a 41C/CV/CX module? Evenmore, is there any supplier of "empty" (just the plastic cover and connector, w/o electronics) modules?

And now the long version of this post:

As this is my first post here I'll briefly present myself.

My first HP calculator was a 28C I bought when it was just released. I remember I spent a lot of time deciding between the 15C and the 41 to be used as my main calculator at the university. During that time, the 28C appeared and it seemed to me the best overall, as I was studying electronic engineering and complex and matrices (also complex) calculations were common.

Realizing that HP calculators were a class on their own I started collecting some of them. Those years, without eBay, the spanish (I'm spanish) market for used HP calculators was small and such collection never grew big, but I was able to find some interesting models (19C, 70, ...). In the mid '90s I stopped collecting new ones.

After many years stored in drawers, I decided to bring back to life some of that vintage HP stuff I collected. To my dismay, two of my three 41 do not work now... that infamous broken posts problem, the only one that survived these years is the only halfnut (a CX).

So, I started looking for solutions, found this forum and here I am.

Now I have some knowledge about howto fix such broken posts problem, but the big problem is... that the HP calculator sickness is again on me!

I've found such really exciting things such as 41CL, NoVs, Clonix, SandMath/Matrix, 41Z, etc that I spent last days collecting all info I can find on them (being TOS a primary reference, in fact I have fired its bandwith alarm two times these days).

So, working now as an engineer, and spending time designing with microprocessor/microcontrollers/FPGAs, I find it fun to perform some experiments with my 41s, looking for other ways to enhance them (if such thing is still possible, seeing the amazing work of Diego, Ángel, Meindert, Monte and many other people).

Modifying the internals of the 41 is not in my list, but the modules... that's another thing.

I imagine a module with a processor on it (as Clonix/NoVs) capable of, not only supply ROM/RAM, but also processing power. To do some experimentation I need to access the ports, thus looking for some connector to reach the internal flex PCB of the 41. Dismantling an existing module can do the trick, but I prefer my modules to remain as collector's items.

And that' all, regards.

[Hans Brueggemann]

welcome to the forum!
your safest bet is to get your hands on one of those ubiquitous HP82106A memory modules. they are cheap, sometimes around 15 EUR on ebay and basically "worthless" as collector's item.

hans

[TASP]

Welcome!

Might want to consider ordering the thumbdrive and looking at more information first.

I'm new here, and I'm absorbing all kinds of interesting tidbits, and I'm changing my game plan for where I want to take my HP41 collection.

The little memory modules do seem to be pretty worthless, but if you do try reusing the case, first put them in an HP41C and make sure they haven't been dualled which would make them slightly more desirable. There also might be a few in the world that have been dualled with a ROM too. Be a shame to clobber a Diagnostic Rom without realizing it, LOL!

Math Roms on the other hand . . . .

[Dave Frederickson]

Google: opening 41 module site:hpmuseum.org and you'll find HP-41 Module Disassembly.

[emece67]

Thanks to all. I think that Diego's method is the best/safest. Only need to locate some used memory modules to experiment with them.

Regards.

[TASP]

This thread got me thinking, when we see ROMs for sale, or HPIL modules, would the sellers ever bother sticking them in a 41 and Cat 2 them to see if they have been dualled ?

I realize there aren't scads of HPIL modules with a built in Extended I/O or Development ROMS in the world, but there are some. Shame they might slip by unnoticed.