Just out.


The latest version of
HP Solve
has Gene's 10bii+ review and more good stuff.

Edited: 29 Apr 2011, 12:11 p.m.


finally! :-)


I can't wait to see that HP-41 replacement CPU board!


indeed! where can we get that 41 replacement board??



The first set of the boards are spoken for.

Edited: 29 Apr 2011, 4:27 p.m.



I have visited the site but I don't see how to purchase one or get on a waiting list. Any pricing information, etc. available?



Sure, right here:


The link through the business section is broken. Might be a while before the HP website is fixed.


Gene, how does a reference to HP's order page for a business calc answer a question about how to buy a third-party replacement processor for an HP-41? Am I missing something?


doh. I mixed up the 10bII+ with the 41CL.

No order page for the 41CL next set yet. Let Monte get the beta units out and in the hands of a group before he worries about taking orders for more.


Thanks for the info Gene.


I also found the "Tweaking the HP42S" article interesting. Specially in light of the discussion of the WP34S keyboard layout. Although I have to say that I have a BIG problem with putting the X<>Y key on a shifted keyplane (as seems to be suggested by the image). I use X<>Y a lot more frequently than I use RDN and personally would switch those two if I could not have both unshifted.


It is interesting...quickly checking through the models, the only ones I could find which had x<>y shifted were the 17BII, 17BII+, 19BII, 28C/S (swap), 65 and 67. (For the 65/67, x<>Y and Roll down would be primary only if programs using the appropriate LBL had not been defined in program memory. Also, it is interesting that the 34C, 37E and 38E/C had x<>y primary, but roll down shifted.

...but of course, the purpose of articles like these are specifically for creating a dialog and I'm grateful that any sort of discussion might take place.

Jake Schwartz


Hi Jake,

Thanks for the article! Actually of the three business calculators you mention (17BII, 17BII+ and 19BII) the X<>Y and RDN keys are printed as if they are shifted but they act as unshifted keys when in RPN mode.



Jake's new article has ancestors in 2008 as he mentioned in the last paragraph in HP Solve. Looking at them, you'll find tweaking is an hobby with a long tradition in this community, and also the wp34s has its parents and grandparents :-)

I use X<>Y a lot more frequently than I use RDN and personally would switch those two if I could not have both unshifted.

I concur. OTOH only three scientific HPs needed one or both of these functions shifted. Jake listed them.



Concur, I prefer the swap and the roll down functions (and the STO function) all to be unshifted as well.

The keyboard with three shifted functions (not counting the alpha characters) is a bit crazy.

The key layout with the gold shift on top and blue shift on the bottom look the best IMO.


I'll second that on STO! I guess the logic is that you use RCL more than STO so shift STO. However, I like the old Pioneer layout (and the 41 for that matter) with STO, RCL, X<>Y and RDN all unshifted.


I have to say that Gene's review can be used as a "getting started" guide - better than the one provided with the actual calculator. It's that good!

I say this because it helped me to understand some aspects that I did not "get" from the provided guide at a first reading.


Heh. From your lips to HP's ears.

Seriously, all of that material is in there. I have no idea how the quick start guide was written.

The HP 10bII+ is a great little machine.


Well, the quickstargt guide for the 10bII+ is essentially the "getting started" chapter from the original manual. A lot of the new things were put in there, but there wasn't enough space to cover it all.

The QSG *is* enough for you to effectively use the machine however. Unlike the 30b QSG. :-)



Very good stuff.


Very good stuff indeed, thanks!

I took the time to finally solve the cube resistor problem. I never did all the exercises in my textbooks (quite the contrary!). That one was in Resnick & Halliday's book, but I skipped in '82 :-)

7 o---------R---------o 6
|\ /|
| R R |
| \ 2 1 / |
| o-----R-----o-----------+
| | | | |
R R R R |
| | | | +--+--+
| o-----R-----o | | /|\ | 1A
| / 3 4 \ | | | |
| R R | +--+--+
|/ \| |
0 o---------R---------o 5 |
| |
| |
= =

For easy visualization the cube has been redrawn to 2-D. For convenience, let's use 1 ohm resistors. The circuit will be solved through nodal analysis.
Let's take node 0 (ground) as a reference and inject 1 amp into node 1. For convenience, let R = 1 ohm. The seven nodal equations can be readily obtained:

1) (V1 - V6) + (V1 - V2) + (V1 - V4) = 1
2) (V2 - V7) + (V2 - V1) + (V2 - V3) = 0
3) (V3 - V2) + (V3 - V4) + V3 = 0
4) (V4 - V5) + (V4 - V1) + (V4 - V3) = 0
5) V5 + (V5 - V6) + (V5 - V4) = 0
6) (V6 - V5) + (V6 - V7) + (V6 - V1) = 0
7) (V7 - V6) + (V7 - V2) + V7 = 0

Instead of putting the system of equations into matrix form before solving it, the equations may be used exactly as they are written and solved with help of
the hp-50g program described here. The program finds V1 = .833333333333, which implies the equivalent resistance across the nodes 0 and 1 is 5/6*R. Likewise,
when the 1 Amp current source is connected to the nodes 5 or 6, for instance, other equivalent resistances can be determined. They are 7/12*R and 3/4*R,

Sets of equations to be used in the program:

%%HP: T(3)A(D)F(,);
{ 'V1-V6+V1-V2+V1-V4=1,' 'V2-V7+V2-V1+V2-V3=0,' 'V3-V2+V3-V4+V3=0,' 'V4-V5+V4-V1+V4-V3=0,' 'V5+V5-V6+V5-V4=0,' 'V6-V5+V6-V7+V6-V1=0,' 'V7-V6+V7-V2+V7=0,' }

%%HP: T(3)A(D)F(,);
{ 'V1-V6+V1-V2+V1-V4=0,' 'V2-V7+V2-V1+V2-V3=0,' 'V3-V2+V3-V4+V3=0,' 'V4-V5+V4-V1+V4-V3=0,' 'V5+V5-V6+V5-V4=1,' 'V6-V5+V6-V7+V6-V1=0,' 'V7-V6+V7-V2+V7=0,' }

%%HP: T(3)A(D)F(,);
{ 'V1-V6+V1-V2+V1-V4=0,' 'V2-V7+V2-V1+V2-V3=0,' 'V3-V2+V3-V4+V3=0,' 'V4-V5+V4-V1+V4-V3=0,' 'V5+V5-V6+V5-V4=0,' 'V6-V5+V6-V7+V6-V1=1,' 'V7-V6+V7-V2+V7=0,' }


Nicely done.

When I took first year college physics we called it "Halliday & Resnick", probably the 1st edition. (I must be pretty old because whatever edition it was the section on relativity was a supplement!) I need to dig it out and see if that resistor problem is in there.....


Without nodal analysis, an overkill here, the trick would be redrawing the circuit connecting together the nodes clearly at the same potential, like 2 and 4, for instance.
I should have said "Halliday & Resnick". Actually we called it simply Halliday. Mine was probably the Brazilian 1st edition. I think the resistor cube problem is in the chapter 27 (Circuits).


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