HP Forum Archive 16

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HP 33S Impressions Message #1 Posted by Juan J on 14 May 2006, 10:07 p.m. Growing fears that one of my calculators be stolen made me buy a 33S last week. I travel frequently because of my job, and losing or having a calculator stolen is a very real concern for me. I got a CNA411xx calculator with the small decimal point. To my surprise, the keyboard did not feel as cheap as I expected. I am getting used to the weird layout and the small ENTER key. The beast uses two CR2032 batteries, 3V each, and is little more than a 32SII with more memory. How is it that the good old Pioneers managed to operate with 4.5V instead of 6V? A more power-hungry processor, I guess. What is the expected battery life? It has never been a concern for me but after reading the specifications of the 48GII and th 49G+ (little more than a 48 on steroids, I think) it seems something to be careful about. Other than this, this beast feels good in my hand and is reasonably fast, at least for the calculations I need. I am still reading the manual and kept the receipt just in case it stops working or something (you never know with Chinese-made equipment.) I am keying in some programs and equations I use, and will keep the trusty 42S, 41 and 48 at home.

HP 33S Impressions: power consumption and a bit more Message #2 Posted by Vieira, Luiz C. (Brazil) on 14 May 2006, 11:20 p.m., in response to message #1 by Juan J Hola, Juan; about a month ago, I read this post by Trent Moseley mentioning the fact that his HP33S' batteries went dead with no low power indicator. I read that and decided to go ahead with some power consumption (non-destructive...) experiments. I have about half a dozen low voltage CR2032 batteries that I keep for testing purposes, mainly computer mainboard CMOS reliability. I decided to use them in my HP33S so I could see what couold happen, but I did not need to do so. Yeap, I had the same experience Trent had a month ago, but I was not so fortunate: after replacing the batteries, the HP33S had a 'MEMORY CLEAR' message. In fact, I turnned the HP33S on, it went up and reactec to a few keystrokes, then it simply turnned itself off and never got back on with the old batteries (BTW, the ones it came with 2 years ago). Well, I measured the batteries and they were about 1.8V each, and even with this figures (about 3.6Vcc against the expectec 6Vcc), the low power indicator did not turn itself on. Well, 3.6Vcc is almost one single CR2032 (I have measured some fresh CR2032 with about 3.3Vcc). And in these 2 years, I did not use the HP33S so often, just enough to test a few examples and features. Last week I worked with it a bit more in order to write an equivalent program to the original HP41 application to compute transistor bias figures. I was also surprised with the way the HP33S uses memory. In fact, it 'eats' memory. I'd read about this before, but did not have the chance to experience myself. 3 bytes minimum for each program step, 15 bytes if the program step has a number of any size, even a single digit... I did not go any further, I know others have lready done that. But I felt myself surprised, indeed. Well, my unit is one of the first series, and I will keep it anyway. In any case, I'll have a fresh set of CR2032 closer for changing in 2008. Even if there is no 'Low Battery' indication... Cheers. Luiz (Brazil)

Re: HP 33S power -- aren't the batteries wired parallel? Message #3 Posted by Paul Brogger on 14 May 2006, 11:47 p.m., in response to message #2 by Vieira, Luiz C. (Brazil) I thought the two batteries were wired in parallel, not in series, and that the thing was working on ~3v, not 6. (I guess I inferred that from the labels that caution the user to change them one at a time -- if they were in series, it wouldn't matter which was taken out, a missing one would break the circuit.) But, maybe I'm being a little naive?

Re: HP 33S power -- aren't the batteries wired parallel? Message #4 Posted by Vieira, Luiz C. (Brazil) on 15 May 2006, 12:25 a.m., in response to message #3 by Paul Brogger Hi, Paul; I have not seen batteries connected in parallel but in electronic experiences. The most common way to use two (or more) batteries in parallel in practical applications would be by using a small resistor in series with each of them. The parallel connection of any voltage source set implies in increasing of available current (amps) to the connected load, and if one of the sources has a voltage drop, it becomes a load to the other sources. This analysis applies to small-value voltage/current sources, not to the big ones used as power sources in load flow analysis, that would have a different behavior. Current sources may be connected in parallel, though. I'll measure the voltage in the HP33S later, but I'd be much surprised if they are connected in parallel. And apologetic, of course... Cheers. Luiz (Brazil)

Re: HP 33S power -- aren't the batteries wired parallel? Message #5 Posted by John Limpert on 15 May 2006, 6:57 a.m., in response to message #4 by Vieira, Luiz C. (Brazil) Nominal supply voltage for the CPU in the HP-33S is 3.0 V.

Re: HP 33S power -- aren't the batteries wired parallel? Message #6 Posted by Vieira, Luiz C. (Brazil) on 15 May 2006, 7:47 a.m., in response to message #5 by John Limpert Hi, John; Would each battery supply voltage to different parts of the circuit? Maybe one to the processor and memory, and the other to the LCD driving circuit? Have you checked for this? Or they are arrenged in a different way? As always, now I'm curious. Thanks! Luiz (Brazil)

Re: HP 33S Impressions Message #7 Posted by John Smitherman on 15 May 2006, 7:14 a.m., in response to message #1 by Juan J Hi Juan. I got about 18 months on a set with light to moderate use. The low battery indicator did not come on until I ran a program. Regards, John

Re: HP 33S Impressions Message #8 Posted by Juan J on 15 May 2006, 3:29 p.m., in response to message #7 by John Smitherman Hello Guys, Thank you for your input on what to expect from the 33S in terms of bettery life. Now I have a better idea of it. I would say it is good enough for everyday use away from home that is replaceable and, to some extent, expendable. Is there anything else to keep in mind about this beast aside from what has been discussed recently? Again, thanks a lot

Re: HP 33S Impressions Message #9 Posted by Bruno Ferard on 16 May 2006, 7:52 a.m., in response to message #8 by Juan J For my personal experience, I've seen the the calculator speed is divided by 2 as soon as the "low battery" signal is lit. Not a real problem for every day, but it's better to know before running benchmarks with your friends' calculators. Apart from that, give the limited number of labels, I recommend that you note somewhere on a paper which one you use for which program before getting lost. I am also rather pleased with my CNA4xxx HP33s, but my greatest frustration is the shallow stack (4 nubmers only). I am used to the infinite stack of my HP 28S, and it already happened that I lost intermediate results pushed out of the stack. Therefore I wrote a simple "stack saver" program that I call with XEQ S: it copies the stack into variables T,U,V,W, keeping the stack unaltered. The tiny decimal point is not a real problem, since I changed it into a comma! I hope you'll enjoy your 33S.

Re: HP 33S Program Commenting Message #10 Posted by Paul Brogger on 16 May 2006, 11:03 a.m., in response to message #9 by Bruno Ferard FYI, there's a way to use equations to comment your 33s programs that (I think) works nicely. An example: my 3D vector cross-product routine is in label X, and starts: X0001 LBL X X0002 FS? 10 X0003 VECT CROSS PROD . . . X0007 RTN Line X0003 is an equation. With flag 10 clear (typical), the equation is skipped. I start all my 33s routines this way, to keep track of what each is for. It's a useful way to make use of some of the 33s' extra memory.

Re: HP 33S Program Commenting Message #11 Posted by Antonio Maschio (Italy) on 16 May 2006, 12:25 p.m., in response to message #10 by Paul Brogger Here's a very clever way to use this huge (and maybe quite unuseful) HP-33s memory. I had never thought about comments. And consider I'm an experienced programmer in C, who comments all the commentable! Thanks. -- Antonio

Re: HP 33S Program Commenting Message #12 Posted by e.young on 16 May 2006, 1:03 p.m., in response to message #10 by Paul Brogger I do the same thing. I also use a comment before each input variable that describes what the variable is. For example, in a program to calculate the allowable bending stress for an unbraced beam, before "R?" appears, I have a comment line that says "RT RAD GYRATE". That way, if I don't use the program for a while I understand what the variables are without having to go through my written documentation of the program.

Re: HP 33S Variable INPUT Commenting Message #13 Posted by Paul Brogger on 16 May 2006, 2:27 p.m., in response to message #12 by e.young . . . and Flag 10 may be used to flash such a description immediately prior to execution of its associated INPUT statement. (That's a nice UI feature.)

Re: HP 33S Program Commenting Message #14 Posted by Ed Look on 18 May 2006, 12:01 p.m., in response to message #10 by Paul Brogger To quote Gomez Addams (U.S. T.V. character of yesteryear), now this is a "Capital Idea"!! Out of habit from programming old Spices like my old 34C, and even the relatively more capacious 48G and 48G+, you tried your best to conserve program memory (to cram in maybe one more small routine!) by trying to be as efficient as possible in the executable steps and never "waste" lines with comments or unnecessary display steps. It didn't occur to me to do this. Good thinking!

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