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HP Forum Archive 06

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HP42s
Message #1 Posted by Chuck on 16 July 2001, 3:03 p.m.

Since 1980 I've used the HP 11C, 15C, 28S, 32SII, 48SX, and the 49G (G for Garbage!!) along with many TI's (sorry). My calculator of choice is the 32SII for its simplicity. However, I would like similar programming power to the 48SX but without the size. Is the 42s worth the $200 it seems to be getting? Appreciate your comments.

      
Re: HP42s
Message #2 Posted by Daniel Diggelman on 16 July 2001, 4:28 p.m.,
in response to message #1 by Chuck

My first programmable was a HP41CV followed by HP41CX, HP11C, HP71B, HP48SX, HP48GX and finally the HP49G. A few weeks ago I acquired a new HP42S which is a really nice gadget for a HP41 freak. The machine has many good features like COMPLEX MATH / SOLVER / MATRIX / STATISTICS / BASE CONVERSIONS / PROBABILITY and everything is menu driven. The dislikes are the low contrast LCD and the unusual ALPHA entry. As the memory can't be backed up I'm not too keen on entering loads of programs. My $190 HP42S isn't thought to be used every day. I'll possibly soon buy a HP32SII for daily use.

Cheers Daniel

      
Re: HP42s
Message #3 Posted by Steven Soto on 16 July 2001, 5:31 p.m.,
in response to message #1 by Chuck

Chuck,

Since high school (1987) I've used: (in order) 32S, 42S, 28S, 15C, 41CV, 32SII and 48GX. The 42S is by far my favorite. It is small, light, durable and powerful. The 42S was my second calculator of the ones listed, and I still use the same one. I recently acquired one to keep as a backup, as I don't have the discipline to leave my 42 at home like I know I should.

I write at and delete at least two programs a week, usually less than thirty lines, to do small tasks such as interpolation, repetitive tasks, and numerical integration, or to solve. This is the reason the 42 is my favorite. The programs are simple to write, and I can store lots of them. If I have to do a calculation more than three times, I write a program. If I need to use "strange" functions like erf, bessel, or probability functions, I use the integration function and write a program to find functions I would otherwise have to look up (and then carry around) from a book. If I have a nasty function that requires iteration, I write a program and use the solver. I do not want to give you the impression that I am some sort of programming expert. It's just that easy. The 42 is the only "language" I can program in.

I do not find the alpha mode cumbersome, as Daniel does. After you get used to it, it's a breeze. I could stand to have a greek alphabet, but it's not a major drawback with named variables.

In short, I will pay whatever I have to in order to always have a 42 with me. And I'm CHEAP! Get one, and you won't regret it.

            
Re: HP42s
Message #4 Posted by Chuck on 16 July 2001, 6:04 p.m.,
in response to message #3 by Steven Soto

Thanks for the feedback. I guess it's time to look for a "new" 42S and trade away one of my spare 28S. Also, how do you convince the wife that this box with 20 calculators in it needs one more? :-)

                  
Re: HP42s
Message #5 Posted by Daniel Diggelmann on 16 July 2001, 6:26 p.m.,
in response to message #4 by Chuck

Well the answer to convince your wife is easy but expensive. You'll possibly better sell some more of your HPs, get a new HP42S and give your wife $200 for her hobbies. But even if this HP42S will cost you $400 it's worth it :) You've just touched a very delicate subject ...

                        
Re: HP42s
Message #6 Posted by Bill on 16 July 2001, 8:55 p.m.,
in response to message #5 by Daniel Diggelmann

I had a 42S and it is probably the best calculator made. I found I wasn’t using the 42S at work because I might break it so it just sat in my desk. In addition, I converted most of my daily programs to Excel spreadsheets. I eventually sold the 42S for a fair price and bought a 32Sii on sale for ¼ of the price I got for my 42S. For day to day it is great but I really miss the 42S. I got a 48G+ (I wanted a new toy) and it is great but not nearly as functional as the 42S. Buy one if you can!

Bill

      
Re: HP42s
Message #7 Posted by Jonathan on 16 July 2001, 11:47 p.m.,
in response to message #1 by Chuck

A little off subject, but I felt it was still appropriate...

Does anyone know the real reason why HP discontinued the HP-42S? There's obviously a demand; people are willing to pay more for it today than what it cost originally! Was the HP-48 supposed to be the "successor?" I don't think it's a worthy replacement; it's too big, heavy, and complex.

What drove HP to develop on the HP-32S instead of the HP-42S?!!

            
Re: HP42s
Message #8 Posted by Jim L on 17 July 2001, 10:06 p.m.,
in response to message #7 by Jonathan

Years ago when people would ask about the 42S people would praise it but their posts would frequently end with some variation on:

It's a nice calculator but hard to justify when the 48G is only a few dollars more.

So it didn't surprise me when they stopped making them and it also didn't surprise me that canceling them instantly tripled their selling prices on ebay.

      
Re: HP42s
Message #9 Posted by Ron Ross on 17 July 2001, 8:49 a.m.,
in response to message #1 by Chuck

Is it worth $200? I don't know (but if I could only keep one calculator to use and only one, it would be a 42s). I use a 48G at work, I have every LCD Hp model made by Hp except a 16c & 40G. My first Hp was a 15c and I like its layout best, but the 42s is just so easy to use & program and extremely powerful.

If it had a serial port, More RAM, and perhaps a clock for data acquistion purposes and timing, It would be king and be the best engineering tool, period. As it is, it is only just the best pocket calculator ever made.

The Hp32s is a poor second choice, but it is the only viable choice for most. It is a great little calc that sits in the shadow of a mountain.

To get anywhere close to the power of the 42s, you can buy a 19bII (but doesn't have matrix ability), you get a clock, and it has a great stats pack and has trig. But since it is larger, why not just buy a 48G.

If you can live without trig, (Most of us can't) the Hp17b has as good of stats and RAM also. Also RPN and alpha entry and Hp solve.

            
Re: HP42s
Message #10 Posted by Vassilis Prevelakis on 18 July 2001, 4:20 a.m.,
in response to message #9 by Ron Ross

Ron Ross wrote:

> If it had a serial port, More RAM, and perhaps a clock for data acquistion

> purposes and timing, It would be king and be the best engineering tool,

> period. As it is, it is only just the best pocket calculator ever made.

You have just described the HP-48SX with the HP 82210A HP-41CV Emulation Card.

I have this combination and it is awesome. I can call HP-41 programs from 48SX programs and vice versa. It offers both a single line display (like the 41) and a 5 line display with the stack plus the LASTx register.

I can extend the HP-41 instruction set by writing HP-48SX programs. I've written a couple of functions to use the HP-48SX clock.

Also the manual that comes with the card is extremely well written. I have scanned it and submitted it to the HP Museum for their manual collection. Unfortunately they weren't very keen to get the ROM image because of possible copyright probs with HP. If this issue can be settled, I believe that this image would be indispensable to HP-48SX owners.

I do not believe that the image is usable with later 48s or the 49, but I do not have calculator to test. Anybody with more info please let us know.

**vp

                  
Re: HP42s
Message #11 Posted by Ron Ross on 18 July 2001, 8:30 a.m.,
in response to message #10 by Vassilis Prevelakis

No, I did not just describe your 48sx. I said best POCKET calculator ever made. I meant exactly what I said and it does not describe your 48sx. Sorry to bust your bubble. I will not argue and I even concede that the 48 and 49 are superior calculator platforms, but they only fit in backpacks and large leg pockets (but not the smaller shirt pocket) and are not all that field portable in comparison to a 42s. If Hp had provide even a mere 32K ram and a serial port, I would (and so would probably 50% of 48 users) use the 42s exclusively and pay over $200 to get it. JUST those two features, and it would be the calc to own. Without the serial port, any memory loss requires your fingers to keypunch heavily and all programming is done via keyboard (not an enjoyable task).

                        
Re: HP42s
Message #12 Posted by Tony Duell on 18 July 2001, 2:18 p.m.,
in response to message #11 by Ron Ross

Odd... I've just put my HP49G in my _shirt_ pocket to prove it will fit there. It does. Almost perfectly. Incidentally, I assume you realise you can upgrade an HP42S to 32K RAM (I call the result a 42SV, of course ;-)). You have to open it up then remove the 8K RAM chip (the only 28 pin chip on the board), solder a 62256 32K RAM in place of it, and cut one jumper pad near pin 28 of this chip and solder across one alongside it (this changes the function of pin 26 of the chip from CS2 (which is tied to Vcc) to one of the address lines). The machine will then recognice the extra memory. Of course you want to use a low power CMOS RAM chip. This doesn't alter the fact that without a serial port it's painful to program all that memory, and a MEMORY LOST just increases that pain :-( I'm sticking to my HP41 system. It's a little larger than the HP42S (OK, it's a lot larger with all the peripherals I have), but it's a lot more powerful because of all those peripherals.

                              
Re: HP42s
Message #13 Posted by Ron Ross on 18 July 2001, 3:42 p.m.,
in response to message #12 by Tony Duell

I've heard other people make attempts that were unsuccessful. However your post's sounds like you have had success. I also have heard of a serial port being added to the Hp28 line and am curious to modify the 42 also since they both have the IR output.

I am somewhat chicken to open my 42s, but the option of more RAM and a serial port just might make me go for it.

Thanks

                                    
Re: HP42s
Message #14 Posted by Tony Duell on 18 July 2001, 5:51 p.m.,
in response to message #13 by Ron Ross

I've upgraded 2 HP42S machines to 32K at HPCC meetings. Probably not the best place to do them (surface mount soldering is easier when you're not being photographed by flash :-)). AFAIK they both work fine still (I did this about 5 years ago). No extra memory losts either. Some 62256s take rather a lot of standby current and will drain the batteries quickly. Pick one that has a low standby current. Apart from changing the chip and cutting one pad and jumpering the other, there are no problems with this modification. Of course it does involve taking a 42S apart (which is not trivial) and it does involve some surface mount soldering. I'd not recomend doing this unless you've got experience of the latter. I don't know if I should say this, but I have not upgraded my own 42S yet. Mainly because I don't use it that much. Of course increasing the memory doesn't get round the problem of the lack of any form of input port. Adding one of those would involve extra (machine code) software, so I've not investigated doing this. The RAM mod is quick and easy, hacking the machine's software is not.

                                          
Re: HP42s -- 32K Memory Upgrade
Message #15 Posted by Paul Brogger on 27 Aug 2001, 11:02 a.m.,
in response to message #14 by Tony Duell

With Tony Duell's helpful clarification via email, I've upgraded both of my HP-42S units, and they seem to work fine. It's actually a very simple procedure. (I'll write it up and submit it to Dave for posting as an MoHPC "repairs" article.)

I was aided by a very helpful supplier of electronics, FUTURELEC (www.futurelec.com). At the time of my order, they required no minimum purchase(!) and took extra time to chase down a surface-mount part rather then the DIP device I'd inadvertently ordered. VERY satisfied with these folks' customer service!

Thanks to Tony and to Futurelec.

                                                
Re: HP42s -- 32K Memory Upgrade (A URL Correction)
Message #16 Posted by Paul Brogger on 29 Aug 2001, 9:52 a.m.,
in response to message #15 by Paul Brogger

Sorry, the name of the electronics supplier is "Futurlec", and its web site is at www.futurlec.com .

                              
Question
Message #17 Posted by Iqbal on 18 July 2001, 4:05 p.m.,
in response to message #12 by Tony Duell

How stable is the 32K version?

                              
I/O for non-I/O-enabled calculators (was: Re: HP42s)
Message #18 Posted by John Ioannidis on 18 July 2001, 9:10 p.m.,
in response to message #12 by Tony Duell

Back in the mid-fourteenth century, there was a device that would fit over the keyboard of an IBM Selectric typewriter and turn it into a printer.

Anyone want to help me build such a thing that takes an HP calculator (say, a 42S), uses a camera to read the display, and this way interfaces it to a PC for up/downloading programs?

/ji, only half-joking!

                                    
Re: I/O for non-I/O-enabled calculators (was: Re: HP42s)
Message #19 Posted by db(martinez,california) on 18 July 2001, 10:05 p.m.,
in response to message #18 by John Ioannidis

educalc used to carry a device that took the ir from a 42 and fed it into an i.b.m. but of course it did not work the other way.

                                          
Re: I/O for non-I/O-enabled calculators (was: Re: HP42s)
Message #20 Posted by Tony Duell on 19 July 2001, 7:26 p.m.,
in response to message #19 by db(martinez,california)

Output (from the HP42S to something else is not hard) -- you have the IR printer port. The format of the data is documented (we had a thread on that here a month or so back). Decoding it to something more sane involves a medium-size board of TTL or a single-chip microcontroller depending on your chosen methods of design. I did this with my HP28C about 12 years ago. It's input -- into the HP42S -- that's hard. There is no input port, documented or not.

                                                
Re: I/O for non-I/O-enabled calculators (was: Re: HP42s)
Message #21 Posted by Andrés C. Rodríguez (Argentina) on 20 July 2001, 7:31 a.m.,
in response to message #20 by Tony Duell

Decoding the printer bit stream (IR) is well commented by Steve (Australia) in the articles forum, here at the Museum. He managed to use the input port of a PC sound board with almost no extra hardware.

Let me just say that I enjoy these threads about I/O for the HP42S, and certainly enjoy the spirit of hacking (in the proper sense) such things. But I must say to anyone who has a decent, working 42S, DONT RISK IT UNNECESARILY!!.

If you like to do some I/O experiments, or to have more memory, think about buying a 48G or G+ (even a used one).

It will not fit your pocket, it is very hard to understand from a 41-42 background, it will complain to you any time you try to do something it doesn't like (pressing the back arrow to clear an already cleared stack, for instance), but it is still available, reasonably priced, it has full serial and bidirectional IR interfaces, and you will not miss it too much if it gets lost or damaged...

                                                      
Re: I/O for non-I/O-enabled calculators (was: Re: HP42s)
Message #22 Posted by Tony Duell on 20 July 2001, 2:06 p.m.,
in response to message #21 by Andrés C. Rodríguez (Argentina)

There was a program years ago (about the time of the 28C/28S) that used an IR receiver module (like the ones used in TV sets for remote control) connected to one of the input pins on a PC printer port. It seemed to work OK. But I don't generally like minimal-hardware solutions for PCs. All too often the software is distributed as a binary-only for some particular OS. Which is useless for people who run a different OS. And even when the source is available, it's often very hard to port hardware-related programs to other OSes. And of course they assume you're running a PC. From where I am sitting here I can see 2 PCs and a dozen computers which don't have Intel processors in them. Heck, a couple of them don't even have microprocessors in them. So I prefer to make a little bit of hardware (probably microcontroller-based) that interfaces between the HP calculator and a standard interface (Centronics parallel, RS232, etc). Anyway, I knocked up a board of TTL to decode the HP IR printer stream in a couple of afternoons, and it's worked fine ever since. As regards I/O on the 42S, I guess if you want a 42-a-like with I/O you should get a 41. You then have the card reader, wand, printer, IR printer, HPIL, and so on. I use my HP41 a lot more than the 42... My 42, actually, generally gets used as a simple scientific calculator in the workshop. For calcuating thread depths, changewheel ratios and so on. It's falling into a pool of cutting oil a couple of times -- fortunately it's an HP so it doesn't mind too much :-). I guess you'd call that 'risking a 42S', though... Finally, as I said before, the 49G _will_ fit in my pocket....

                                    
Re: I/O for non-I/O-enabled calculators (was: Re: HP42s)
Message #23 Posted by Andrés C. Rodríguez (Argentina) on 19 July 2001, 8:40 a.m.,
in response to message #18 by John Ioannidis

HP used a "button pusher" device to test the Woodstock calculators as part of QA (there was a photo in a HP Digest magazine, around 1977-1979).

If someone is interested enough to risk a working HP42 (certainly not me), the use of CMOS analog switches, wired to the keyboard row and column lines, may produce "artificial keypresses" under control from a PC or other device (alarms, sensors). It is simple on the hardware side, but the controlling software will need to have some sort of USER, MENU, ALPHA "awareness"...

For control projects, a running program using GETKEY is a good way to poll such signals.

For the output side, we have the IR on the HP42S, but you can also use the pulse train sent to the piezo buzzer and control it with TONE instructions. See my article in the memories forum, here at the Museum, where I comment on my experiments (not very successful) trying to have cheap IO on my HP41 (HP-IL was very expensive for me at the time...)

                                          
Re: I/O for non-I/O-enabled calculators (was: Re: HP42s)
Message #24 Posted by Tony Duell on 19 July 2001, 7:38 p.m.,
in response to message #23 by Andrés C. Rodríguez (Argentina)

The problem with modifying a 42S is that there's no way to transfer programs between 42S's. If there was, then it would be reasonable to modify one machine, download programs into it, and then transfer them to another, unmodified 42S. But as it is, you have to modify every machine you want to be able to download programs into, and you have to carry a modified machine (presumably with extra connectors on it, and more likely to be damaged by electrostatic discharge) around with you. I'd rather make a button-pusher. Incidentally, one way to download stuff into an HP41C, etc without HPIL is to modify the 82153 barcode wand. Crack open the interface module and solder the transistor side of an optoisolator to the wand wires (emitter to black (ground), collector to white (signal)). Passing a current through the LED part of the optoisolator is the equivalent to the wand being over a white piece of paper with the switch pressed. It's not hard to send suitable pulses to the LED to simulate barcode, and thus download stuff to the 41. This has been mentioned a couple of times (at least) in PPC journal. It's also an ongoing project here at the moment -- when I've finally got it all working (if I do...), I'll make the source code, etc available.

                                    
Re: I/O for non-I/O-enabled calculators (was: Re: HP42s)
Message #25 Posted by Paul Brogger on 19 July 2001, 11:33 a.m.,
in response to message #18 by John Ioannidis

I think the best installation would be the insertion of a precisely fabricated ribbon cable between the contacts of the keyboard/PCB interface, thereby carrying the 15 keyboard traces out to a tiny external connector. This would presumably be a flexible mylar-based strip which would narrow as it wrapped around the low end of the PCB, or it might take a right-angle bend behind the LCD and out one side of the calculator.

This "mechanical" external connection would enable the CMOS switches, etc. to be implemented entirely external to the calculator, and powered through the PC interface. (If magnetic relays were used, the interface would be a direct simulation of keystrokes, without regard to power levels, polarity, etc.)

I've got a couple of 42S machines open and possibly available for experimentation. But better yet, the same installation could be developed on an HP-17BII, and would work for all the Pioneers. (They all have the same keyboard internals.)

So, take the IR cover off of your 42S. If we could fit a fifteen-pin connector of some sort between the IR LED and the battery compartment, (about 3/8" by 1/4") that would be best. Another alternative would be a flat connector through the side of the back case.

So, anyone interested should grab a low-value Pioneer, pry it apart (no, you DON'T need to take the foil off the front -- see my directions under "Pioneer Repairs", elsewhere), and start poking around. This looks entirely doable!

                                          
Re: I/O for non-I/O-enabled calculators (was: Re: HP42s)
Message #26 Posted by Paul Brogger on 19 July 2001, 11:41 a.m.,
in response to message #25 by Paul Brogger

P.S:

Inserting something between the keyboard/PCB interface would require taking the PCB away from the keyboard/display unit -- an operation not without risk.

But all the CPU contacts are on the exposed side of the PCB, and all the keyboard traces appear to feed through from the hidden (interface) side. Therefore, it should be possible to identify the feed-through holes for the keyboard traces and solder a wiring harness to them, without further disassembly of the calculator. (See my internal pictures of the PCB, etc. under the MoHPC article on the 42S.)

                                    
Re: I/O for non-I/O-enabled calculators (was: Re: HP42s)
Message #27 Posted by Tony Duell on 19 July 2001, 7:23 p.m.,
in response to message #18 by John Ioannidis

I believe that HP service centres had automatic 'button pushers' for some families of HP calculators. Adter doing a repair, this thing would push the keys in a given sequence, using all fuctions on the calculator. At the end of the sequence, the operator would check that the display showed the right value. It would be possible to make one for the 42S, such that you could tell it which key to press from a PC. A future project, perhaps...


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