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HP Forum Archive 11

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advise on hp 28s needed
Message #1 Posted by lokhin on 3 Apr 2003, 8:18 p.m.

hello, fellow hp users,

I am relatively new and know little about hp history. I was 3 when hp 28s first introduced.

I got a chance to take part in an online auction for an hp 28s starting from us$25 in my city.

any comments on the hp 28s? is it good to be used as a graphic calculator? and do you prefer it to an hp 42s or hp 32sii??

yes, I have read the hp 28s article in the museum


I don't like them, but don't let that stop you.
Message #2 Posted by Jeremy on 3 Apr 2003, 9:04 p.m.,
in response to message #1 by lokhin

I don't have one, but I have handled one. The screen doesn't look big enough to really do any graphing, but I think it's probably fine for everything else. I also don't like how many of the basic scientific functions are shifted or in a menu somewhere.

I bought a 32SII on eBay a week or so ago, and I really like that one. I also have a 48G, which is pretty good for graphing. I have to admit, for graphing, I like the TIs better. They are much faster and it is easier to zoom in and such.

I haven't figured out how to program either of my programmable HPs yet. Ironically, it is because I don't have time on account of my school work. I have to spend time writing lab reports and studying the texts rather than HP manuals.

Another thing that bugs me (again, no personal experience in this) is that since there are keys on both sides, there are either bending conductors are wiper contacts. This makes the 28 series more prone to wearing out than many other HPs. (The less moving parts, the more reliable)

On the flipside, the 48G series is very complicated and hard to use compared to many other HPs. But if you could only get one, I would get one of those. Since you wouldn't be spending time messing around with all these others, you could spend some time and learn how to use it to the utmost.

Sorry for all the babbling.


Re: advise on hp 28s needed
Message #3 Posted by Gray Wilson on 3 Apr 2003, 11:24 p.m.,
in response to message #1 by lokhin

I've used my 28S for 12 years as my daily calculator. I've found it a fine machine. Don't be fooled by its clean appearance - it's a very powerful scientific calculator. But I don't use it for graphing; Mathematica or MathCad programs are much better for that.

I really like its viewable unlimited stack and RPL programming style. I think the keyboard is one of the best ever produced by HP - the keys presses are gently click-positive, more like the later 32SIIs, without being "heavy" like the 42S or 48G. And the layout is clean and uncluttered, like the 42S and unlike the 32SII and 48G.

I think all 28S's were made in the USA or Singapore and certainly have superior external quality to the later 48Gs and 32SIIs. Although the 28S screen is not as crisp as the latest "black" screens of the Gs, it is perfectly legible.

Also, unlike the 32SII and 42S you can't hold it in one hand and have easy access to the keyboard. It's possible, but cumbersome. Also, unlike other HP calcs, the display doesn't show thousands separators, which can make numbers in the range 1E6 to 1E12 difficult to read.

Also, unlike the 48G the only way to input programs is via the keyboard.

In my opinion, the 28S is a much under-appreciated machine. It is very like the 48G in its programming style, but doesn't have the PC connectivity, expandability (of the 48GX)and much larger memory capacities of the 48GX and G+. But I've found its 32K more than enough for the programs I've written over the years. The 32SII only has 360 some bytes and the 42S about 7K.

If you do get the calculator make sure you get the owners manual and reference manual, both of which came standard with the calculator.

Re: advise on hp 28s needed
Message #4 Posted by John K. (US) on 3 Apr 2003, 11:34 p.m.,
in response to message #1 by lokhin

For the most part, I agree with Jeremy. For $25 though, it's not a bad buy -- more so if it comes with manuals. In a direct comparison, the 48 (of any flavor) wins in nearly every category: speed, durability, memory, screen size, I/O, and so on. To top it all off, the "N" size batteries used by the 28 (it requires three of them) are becoming increasingly difficult to find -- in the US, at least.

Still, they have their fans. The extra keys make it marginally easier to program (you don't have to exit alpha mode to get at the soft-keys) and they are slightly smaller in overall dimensions. Plus, HP made a really nice leather pouch for them which is still available from at least one vendor that I'm aware of.

If you decide to buy one, be sure to find out the condition of the battery door and the plastic surrounding the battery compartment opening. Ask for pictures, if possible. The plastic in that area is notoriously weak and the contact springs are very stiff making it the most likely point of failure during normal use.

Re: advise on hp 28s needed
Message #5 Posted by lokhin on 4 Apr 2003, 6:17 a.m.,
in response to message #4 by John K. (US)


thanks for the input.

it seems that the hp 28s strengths are the relatively large memory and the larger keyboard, and its weakness are the lack of I/O, the weak battery door and clean keyboard. i am not sure if the foldable design is a weakness or strength.

is it a good choice, provided that it is cheap??

some more questions come to my mind...:

i know and have an hp 32sii, and think that it is a very well designed calculator. may i know in what way the hp 42s keyboard design is better than that of an hp 32sii? I tried the emulator and a lot of menus are involved... the hp 32sii has a less cluttered keyboard (has 2 shift keys) which is more preferable?

thank you again


Re: advise on hp 28s needed
Message #6 Posted by John K. (US) on 4 Apr 2003, 7:08 a.m.,
in response to message #5 by lokhin

> it seems that the hp 28s strengths are the relatively large memory[.]

Large memory relative to the 32SII? Yes. Relative to the 48? In the case of the 48SX, 48G+ or 48GX, no. Still, 32K (in the case of the 28S -- the 28C only had 2KB, which really isn't enough for an RPL system) is pretty good, considering the I/O limitations.

> is it a good choice, provided that it is cheap??

Just to play with RPL? Sure, I'd go for a sub-US$30 28S. I might even pay a US$5 premium for manuals. Too much more than that, though, and you'd be better off looking for a 48, in my opinion.

> may i know in what way the hp 42s keyboard design is better than that of an hp 32sii? I tried the emulator and a lot of menus are involved... the hp 32sii has a less cluttered keyboard (has 2 shift keys) which is more preferable?

This is really a matter of taste. Some feel that the 32SII keyboard is visually confusing, others don't like to have to wade through the 42S's menus. The 42S does have the advantage of customizable soft-keys, so you can assign up to 24 commands or programs to a menu key. And if you use the programmable menus creatively, there is really no limit to how many things you can assign to the top row.

Personally, I like the 42S better than the 32SII overall. But the 32SII is what rides around in my backpack. ;^)

I hope this helps.

Re: advise on hp 28s needed
Message #7 Posted by John Smith on 4 Apr 2003, 7:30 a.m.,
in response to message #1 by lokhin

The HP28S (and its former incarnation, the HP28C) is a truly revolutionary calculator, a milestone in calculator art, and as such it is immensely valuable for us collectors.

But its value as a daily-use calculator is debatable. It's got lots of good points, of course, but the bad ones are truly bad, namely:

1) Many basic functions not directly available, you must use menus all the time

2) quite big and heavy, it doesn't fit comfortably in the hand at all

3) the double keyboard is more of a nuisance than a help, actually, and the flexible connector wears out eventually

4) the battery compartment & door design is a real crime: either the batteries inside are just too loose, and make eventual bad contact, so RAM is cleared and you lose all your programs and data, or else fit inside so tightly that there's no way you can remove them (specially the innermost one) before the capacitor discharges, so losing again all your data.

5) Further, the battery door and its surrounding plastic is incredibly hard to put in place and breaks extremely easy, thus making battery replacement utterly difficult, ending most of the time in memory lost. And of course, having 32k full of programs and data is next to useless if you get to lose them and having to re-key them each and every time you have to change batteries. You'll only need to do this every few months or so, depending on use, but combined with the risk of damaging the battery door, thus rendering the calculator useless, that's just too much.

In other words, from a collector's perspective, get one as fast as you can, NIB preferably. But for actual use, you'll be best advised to get an HP42S if you can live without graphics, and some 48/49 model otherwise.

Re: advise on hp 28s needed
Message #8 Posted by lokhin on 4 Apr 2003, 12:56 p.m.,
in response to message #1 by lokhin

it seems that the hp 28s graphics is not very usable, how does it works?

in the stat mode, i know that it can plot scatter plots, but can it plot regression lines?

it seems that it does not have a solver?


Re: advise on hp 28s needed
Message #9 Posted by dano on 4 Apr 2003, 9:24 p.m.,
in response to message #8 by lokhin

I have both a 28S and a 48G - actually many other hp calcs too but I keep both the 28S and 48G handy by the computer. As they are both the later generation RPL calc, their internals are rather similar. The 28S (and the C) do have the solver. An excellent source on the 28 series is the August 87 issue of the Hewlett Packard Journal that is on CD 3 of the HP museum on CD. It includes articles on the mechanical design, RPL, and the new solver that debuts on this model. The folding hinge is discussed in detail and once you see how it's made, you will have no doubt that it will last. They don't mention the battery door at all and I must say it is by far the weakest point of the calc - or any of the HP calcs I own. I cringe every time I have to open and close it up. Frankly I like the 28S better than the 48 but only if you have some desk space to lay it out - A quick read through the 28 manual and you will be amazed at what it can do. The 48 just seems too cluttered. Also, I never needed to program or graph on either one so I can't really comment on that (I use the 41 and 42S for programming).

Re: advise on hp 28s needed
Message #10 Posted by lokhin on 5 Apr 2003, 8:29 a.m.,
in response to message #9 by dano


any comment on hp 42s programming then?

I think the 2 cases are similar, no way to input without using the calculator keyboard, but lots of room to program, for the 2 machines...

but is the feature that hp 42s is compatible with an hp 41c program an advantage??


Re: 42S, 41 programming
Message #11 Posted by dano on 5 Apr 2003, 12:54 p.m.,
in response to message #10 by lokhin

I learned to program with the 41, it was my first RPN calculator back in college. I got pretty good at it and found I had a lot of programs so I bought a card reader. But that was years ago and now if I need any EE analysis I do it on the computer. I really like the size and form of the pioneer series so I got a 42S and I love it but I probably don't use 1/10th of it's capabilities. If I need a quick and dirty program, I'll do it on the 42s. It's fully compatible with the 41 so I don't have to learn anything new. But honestly, I don't do much programming any more and I wouldn't write a long program on the 42s because if the batteries died - it's gone unless you print it out on the 82240 (which I have) but you end up having to type it in again. Dan

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