HP Calculator Stuff

Last Update: 05/25/99
I'm just starting this page...

Museum

Customizing the 41

HP-41 Parts for Sale

Misc Parts for Sale

There's so much information...

When was the HP-35 introduced?
What was the first HP Calculator?
What is your old calculator worth?
What is RPN?
How to fix up those batteries...
HP made a watch too?
Want to buy?  For sale?

Dave Hicks has done a magnificent job, so
Go see the Museum of HP Calculators!

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Customizing the HP-41

I don't do the work anymore, either the parts are getting smaller or they're simply getting harder to see...

I sped up hundreds of HP-41s.  By changing the values of a few simple components, the CPU can be made to run almost twice as fast.  Also a latching, magnetic reed switch was added so that you could select normal or fast speeds externally, without altering the outside of the 41 case.  I provided a custom manufactured magnet that lives in the AC tunnel cover so it was always available.

I combined many modules or put them inside.  RAM and ROM can share the same address space (if my memory is correct).  So the result is that I was able to combine as many as 3 ROMs in a single package, thus leaving more ports available for Card Reader, Wand, IL loop, etc.  The timer module could even be put inside the 41 so you never had to plug it in or out again.

The timer module can also be wired for external electrical control.  Imagine timing an external function and getting exact measurements because the switch was event driven instead of finger driven...

Since I used to work on this stuff I have a few parts leftover...

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HP Parts for Sale

Screws:Screws.jpg (56788 bytes)
Feet: <pic>
Labels: <pic>
Port Covers: <pic>
Tunnel Covers: <pic>

Lots more to come, give me a few days...

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Misc Parts for Sale

Magnets: <pic>
Reed Relays: <pic>

Lots more to come, give me a few days...

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