Replacement for HP41CX



#22

Hi,
I am looking for a replacement calculator for my old HP41CX which is failing.
I have been looking at the HP33s.
I am not interested in graphing calculators.
I look forward to hearing your comments on whether the HP33s is suitable for general engineering use and occasional programmability.

Regards
Phil Green


#23

I have an old hp41cv calculator,do you have an idea about the battery voltage needed (4 batteries x volt each)


#24

They're standard 'N' cells, 1.5V each. In the UK they're even available at some supermarkets.

Do NOT use the similar-sized 12V batteries used in car alarm key fobs, cigarette lighters, etc. 48V (4 of those in series) will ruin an HP41.


#25

I thought that at the HP website they recommended the 48 as replacement for the 41.

#26

Phil,

There is a boatload of discussion in the Forum Archives about the 33s. Some people like the 33s just fine, some people don't like some things but think it is OK in general, and some people absolutely loath it (particularly its unique "styling"). The early models had some non-trivial bugs that were rectified. The decimal point in the display was almost unreadable, that has been corrected (as shown here.) The current version exhibits some inaccuracies in certain functions (in the 9th or 10th decimal place) which are either trivial as far as real world use or abominations, depending on your point of view. I'm not sure if there is really a general consensus, but in my opinion, the answer to your question is yes, the 33s is suitable for general engineering use and occasional programming. To avoid the early bugs and the bad display, get a unit with a serial number that begins with about CNA 532 or later. In case you are unfamiliar, the serial number will be of the form CNA YWWxxxxx, where Y+2000 is the year of manufacture, WW is a two-digit number indicating the week within the year, and xxxxx is a 5 digit number unique to each calculator. The serial number is on the back of the calculator, but is also on a sticker on the outside of the packaging. If you order on-line or otherwise can’t hold the package in your hand before you buy, require the seller to assure you that the serial number will be proper.

Edited: 8 Feb 2007, 8:11 a.m.


#27

I have revisited the 33S in recent weeks, mostly out of interest in porting some HP41 programs in hopes they will run a bit faster. I am not so troubled anymore about the Cosine Bug (i.e., some glitch in the algorithm gives less than full 12 digit accuracy for cos and tan for angles close to 90 degrees), but must admit that even though it is not a full blown abomination it is a wee bit of an embarrassment for the calculator.

What continues to be a source of lament for me is the incongruity of having a whole bunch of memory for programs and equations (almost 5x that of the 42s and 15x that of the 41CV and CX), yet limitations on programmability that make it hard to take full advantage of that. There are 26 lettered registers and 6 statistics registers that can be used for storage only by indirection, plus the index register. This is a hard cap--there is no movable partition between program memory and storage memory like there is in the 41, 11C, 15C, and 34C (to name a few). Most reasonable programs don't require more than a few registers, but anything that involves matrix computation with matrices of any size is essentially ruled out. (That said, someone here did share recently that the 33S got him through some tough matrix computations on an engineering examination.)

I particularly lament the serious restriction on available program labels. There are only 26 lettered labels available. There are no multicharacter string labels or numeric labels, and there is no distinction between local and global labels. This means that if I have a program labelled A that uses within it labels B thru E, those five labels cannot be used elsewhere throughout the calculator for another program--i.e., if my next program is F, I can't re-use the label D again as a branch point or I will get an error. The difference between global alpha, local alpha, and local numeric labels in HP41 programs is great organizing feature and I miss its replication in the 33S.

I also really miss the lack of stack based register arithmetic. For example, in several of J-M Baillard's excellent advanced math routines for the HP41, he often uses something like "ST+ X" as a quick way to double the contents of the X register or "ISG Y" to add one to the Y register, and much of his computations in iterative routines like series summations and continued fractions involve clever manipulations of the stack and minimal use of storage registers. Indeed, trying to duplicate some of this ingenuity is proving to be my biggest barrier as I try to transfer some of this amazing work to the 33S.

On balance, the 33s does offer RCL arithmetic, like the 42S but unlike the 41 series. Let's say on the HP41 I have something in R15 that I want to leave unmolested but I want to multiply into the what's in the X register. On the HP41 this is a two step task--RCL 15, *. On the 42S this could be done in one step: RCL* 15. Likewise with the 33S, only in that case we are dealing with a lettered register.

For 50 bucks, the 33S is a really good calculator, but it could be a great one. I think if I spend a little more time with it trying to work around its limitations (at least as I see them) I will overlook some the flaws and be impressed by its potential. For example, I already know that it is fast--the built-in integrator with return a six or seven digit result for the famous Kahan integral in well under a minute, whereas in the original 1980 the wonderful 34C took several minutes, even after appropriate transformations were made.

If there was an improvement to the 33S, I would like to see them loose the chevron layout, add numeric and multicharacter labels, and implement some way to partition memory so as to make more storage registers available, even if one could only access the additional registers by indirection (indeed, this is the case on the HP41 and 42S--registers above 99 can only be accessed indirectly).

Finally, I should mention the display. The decimal point on the corrected display is still kind of small, but for the most part I think it is a very clear two line display--clearly superior to that of the much praised 42S.

Happy shopping!

Les


#28

The Hp33s is for a new market, not the 1981 market the Hp41c was targeted for. (I am making an excuse for Hp, AND I am one of the strongest proponents for a newer Hp42sx with 128K RAM, units conversions, a 48g like file/menu structure, and serial I/O).

The new market has access to Excel at the very least or real math packages. Therefore the features you ask for could easily be obtained by using a desktop and most often are. In the early 80's these computational tools were not readily available to the average working engineer.

The Hp33s is meant to replace only two calculators, the Hp32sii and the Hp20s. It is a clone of the Hp32sii in features and functions aside from expanded memory and its rediculous (sp) keyboard. In algebraic mode it still uses AOS, just like the Hp20s. It wasn't meant to replace or compete with anything else. That it is a four stack RPN means that it is the closest thing on the market to replace the Hp41c series if you have one fail.

Summing up, the Hp33s is a pocket RPN programmable calculator for basic number crunching, if you want or need more, you buy a higher end graphics.


#29

It took only a couple of hours for me to rework JM Baillard's routine for the error function (here) into an 84 step routine on the 33s. To my great pleasure it is much faster than its cousin on the 41CV or CX--at most a couple of seconds for typical input, whereas the 41 equivalent can take several seconds in some cases to converge to a good result.

But I have noticed one thing--HP33S programs really gobble the memory. My 84 step 33S routine clocks in at around 400 bytes. Baillard's very compact 80 step 41 routine uses only 110 bytes in that calculator. My 33S doesn't have any of the traditional byte gobblers, like multidigit decimal numbers or alpha strings as steps in the routine per se. I can only conclude that program code on the 33S uses more memory per typical instruction that 41C/CV/CX ard 42S programs typically do.

Good thing the 33s has all that memory. It provides a good buffer for what turn out to be programs that are several times the size of their HP41 predecessors.

After successfully porting this little routine and generating quick answers, my interest in the 33S has been whetted anew. HP41 lovers will find this machine with the weird keyboard can still do some neat things, and do them quite a bit faster too.

Les

Edited: 10 Feb 2007, 11:51 p.m. after one or more responses were posted


#30

Instructions in a program take 3 bytes each, compared to usually 1 or 2 in an HP41 calculator.

That will eat up the memory pretty quick...but with 26 labels, you can't really write 10000 step programs anyway!

Gene


#31

Hi,

if the same label can occur multiple times in a program,

like in the HP-41, then maybe one could start kinda mini-challenge for the 33S.

Who writes a (non-bogus) program with maximum size for the 33S?

Who ports a more advanced program like the 3D TicTacToe,

which is in the Games library for the HP-41, to the 33S ?

This may include the adaption of some programming techniques

commonly used in the HP-41, like indirect jumps, etc...

If the GOTO/GSB search order is like in the HP-41,

then it should be possible to port 3DTTT;-)

Hmmm, maybe this is still too easy,

since the estimated program size will be less than 10K...

Raymond


#32

"if the same label can occur multiple times in a program,
like in the HP-41 [...]"

    No can do

Best regards from V.

#33

Like Valentin pointed out, once a label is used, you can't use it again, period--try keying it in, and you get a "Duplicate Lbl" error.

However, this may not be such a limitation after all. One thing that is quickly becoming clear to me is that the 33S may actually be quite strong when it comes to routines of shorter length that may actually be quite time consuming in execution when they are called repeatedly to some point of convergence. Like I pointed out, my 84 step routine to compute the error function by series or continued fractions is several times faster than analogous routines on my 11C or 41CV, and at least twice as fast as on the 42S. I must admit that, as one who is very interested in recursive routines to compute mathematical functions, this came as a very pleasant surprise. Seeing the 33S offer 11 to 12 digit accuracy in at most 2 seconds where the 41CV takes up to 8 seconds to give 9 or 10 digits really pleased me.

I know this has been asked before, but is there a canonical list out there of the 33S bugs?. So far, the only one that has ever really perturbed me is the trigonometrics of angles close to 90 degrees.

Les

P.S. If I find the time I will submit my 33S listing for the error function to the software library.


#34

Quote:

I know this has been asked before, but is there a canonical list out there of the 33S bugs?. So far, the only one that has ever really perturbed me is the trigonometrics of angles close to 90 degrees.

Les


Les, it looks like Craig Finseth is keeping up with 33s findings at:

http://www.finseth.com/hpdata/hp33s.html

Although I don't see where the trig anomoly has been included.

Regards,

John

#35

Quote:
...is there a canonical list out there of the 33S bugs?

Hello, Les!

Karl Schneider compiled a list recently. In case you have missed the thread, here it is:

http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv016.cgi?read=104145

Regards,

Gerson.

Edited: 11 Feb 2007, 10:17 a.m.


#36

Thanks Gerson.

I have CN6080xxxxx model, so most of the older bugs have likely been resolved.

The modular arithmetic bugs are pretty obscure to me and I think I can live with them for now until I understand them more.

The cosine bug for angles close to 90 degrees is a bit embarrassing for the calculator but of essentially no real-life significance.

However, I must admit that after successfully porting a very "tight" HP41 program to the 33S and watch it run so much more quickly, I really think this much maligned machine can be good for a thing or two!

Les


#37

If anyone is interested, I have prepared a submission for Dave for the software library for the program I have been rambling about. I can send the draft HTML file to anyone who is interested.

Les

#38

Hi, Les --

Quote:
I particularly lament the serious restriction on available program labels. There are only 26 lettered labels available. There are no multicharacter string labels or numeric labels, and there is no distinction between local and global labels. This means that if I have a program labelled A that uses within it labels B thru E, those five labels cannot be used elsewhere throughout the calculator for another program--i.e., if my next program is F, I can't re-use the label D again as a branch point or I will get an error. The difference between global alpha, local alpha, and local numeric labels in HP41 programs is great organizing feature and I miss its replication in the 33S.

As I'm sure you know, the HP-33S was derived from the HP-32SII with its paradigm. The HP-32SII and its predecessor HP-32S had only 384 and 390 bytes of memory, respectively, although most instructions took only 1.5 bytes. 26 labels is plenty for that space, although I wish there'd been at least 2 kB or so of space -- particularly for the HP-32SII, which incorporated the equation functionality from the HP-22S.

I find the paradigm for programming and equations that is shared by all four of the aforementioned models to be quite clever. It allows for intuitive variable and register identifiers without the added complexity of Alpha Mode. It allows for storage of modestly-sized readable, maintainable programs without the need to learn about internal versus external labels, END statements and the like. It is meant to be a paradigm of intermediate capability -- lesser but simpler than that of the HP-41 and HP-42S.

I've thought about how the matrix and complex-number functions of the HP-15C might be adapted and improved for the HP-32SII paradigm, but have not succeeded. The HP-15C works marvelously well, considering the limitations of its paradigm, and the HP-42S improses few limitations with its complexity. Integrating everything that is desirable into the intermediate platform is a challenge.

-- KS


#39

Karl: You wrote:

Quote:

I've thought about how the matrix and complex-number functions of the HP-15C might be adapted and improved for the HP-32SII paradigm, but have not succeeded. The HP-15C works marvelously well, considering the limitations of its paradigm, and the HP-42S improses few limitations with its complexity. Integrating everything that is desirable into the intermediate platform is a challenge.


It is really difficult to do very much with matrix functions on an HP-33s beyond what is done in the "Solutions of Simultaneous Equations" demonstration program on pages 15-12 through 15-20 of the hp33s User's Guide because of the memory limitations; that is, unless you incorporate some sort of methodology such as that which I used in my sixth order and eight order simultaneous equation solutions in Articles 676 and 678 of this site. However, that trick only allows simultaneous equation solutions, not matrix inversions.

When I was doing those programs I was severely stressed by the hp33s methodology for indirect addressing. My problem was that my programmable calculator experience was mostly with the TI-59 plus some experience with the HP-41 where every register can be used for indirect control. When you have used that capability it is really hard work to go back to the i register methodology.

#40

What is the problem with your CX? Is it a fullnut (without frame around display) or halfnut? Why not try to fix it?
If you want I get a look at it, please, contact me. Remove nospam from email.
Best regards
Artur

#41

Hi,

the only true replacement for an HP-41 is...another HP-41 IMHO;-)

As Artur asked, maybe there's a way to get your HP-41 repaired.

The next best relative to the HP-41 is the HP-42S,

but the 42S is even more expensive than an HP-41.

Basically, the 33S is a 'pushed-up' 32SII with more RAM.

However if you don't need the advanced programming

features of an HP-41, maybe the 33S will be sufficient.

Personally, I don't like the keyboard layout, enter key position,

and hard-to-press keys on the 33S, but that's a matter of taste...

Regards

Raymond

Edited: 10 Feb 2007, 10:31 p.m.

#42

I thought my 41CV was failing and off to the dump.

The I discovered FixThatCalc.com.

I was having keypress and displays issue that, I have since learned, can be related to the "pressure only" contact arrangement failing within the calculator--the little posts that hold the screws inside can crack. There are also issues with dirt and corrosion.

I don't know quite what you mean by "failing" but I understand that the overwhelming majority of HP41 problems can be rectified by FixThatCalc, and almost always for the advertised flat rate. I think I paid just under $100USD, and about a fifth of that is my cost to mail the parcel to Pennsylvania.

The ONLY disadvantage is that Randy is so good that his turn around time is of the order of 8 to 10 weeks now, so you will need a temporary replacement. But if you don't want to spend $150 to $300 for a replacement CX, I think the repair is definitely worth it.

Les


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