we need more HP-34C posts


we need more HP-34C posts .......
otherwise I run out of things to talk about



Hey Norm, Mr. Analog guy...

What's that you're talking about?

You talk about LED's, analog stuff, Electronics in general... All of these subjects (and a lot more) fit here, too.

Wanna talk about HP34C programming and usage as well? RPN techniques? All of these subjects apply to other HP calcs, as well. The HP11C has many resources available in the HP34C; the HP15C offers solve and integrate as well. Programming the HP34C is not much different of programming the HP67/97 and both HP11C/15C.

And what about batteries? Woodstocks, Classics, Topcats and Spices use, as standards, rechargeable batteries. Not only the HP34C.

Power sources and power supplies also need analog knowledge. I thought I would read something from you when the subject was standard voltage references for calibrating the 3421A.

See? I'm a nosy guy, as you have already stated... Sometimes I talk too much, I know that. But if I do not ask, how will I know what's the answer?

I've been dealing with some routines for small electrical computations. Some of them fit in the HP34C. Have you tried something like this?

Sometimes I fell as looking for some thread to post messages, but I feel that I'd not add too much after all that's been posted. And sometimes I also wrote more than I should and it may bother some people. But I feel as if I'll always find place if I keep reading.

I think I wrote too much again...

What do you use your HP34C for? Now I'm curious: do you program as well or prefer using it as a daily support?

Best regards. In time: where in the h..k is Captain Zener?

Luiz (Brazil)

P.S. - you were mentioned here... See what I mean?

Edited: 18 July 2003, 11:28 p.m.



You don't write too much--you are always a good read!

So, for old calculators, I reported here that I inherited an old HP 45 with a corroded battery pack. So just tonight, I cleaned out the compartment (I like these classic compartments MUCH better than that absurd gold-plated mylar disaster-waiting-to-happen foisted on the 41). And then I ran down some alkalines until they read 1.25 volts on my father's old US Army Signal Corps Volt-Ohmmeter (Simpson Model 324)-- It is much more fun testing vintage equipment with other even older vintage equipment--and I temporarily wired her up...

So, in short, she WORKS! WhooHoo!!

At first, she was sensitive to pressure on the on-off slider and would only function right if I put light pressure there. But then she apparently warmed up, and worked just fine.

One curiosity, though, is that after running continuously for 10 minutes, the alkaline cells became quite warm. I guess the 0.50 Amps rating stamped on the back is for real! I hope this is not a sign of trouble....

So, next is a more time consuming part---building a new battery pack---but I see some more resources here on that.

Oh, and this calculator got daily use for an engineer's entire career--she shows the wear and tear of a consciensious owner--but all the buttons still work just fine (much better than my recently acquired beat-up 15c) although some of them are a bit softer than others. I think it is really a wonderful thing that this product, made in the 70's--the time of Viet Nam, Israel-Arab Conflict, OPEC Oil Embargo, Stagflation, Disco, Double-knit Polyester, Toxic Waste, LSD and the Clean Water Act, has lasted so long after so much use! (Like, you expect old Victorian Iron to age gracefully, but 70's plastic--what a wonderful surprise!).

Here's the heretical statement--she reminds me of my father's old TI from the 70's---the shape of the keys, layout, the whole RED LED Brick thing---except just more SOLID and SERIOUS (so i guess not so heretical of me after all...)

OH, and serial number:

1349A 20320


Bill Platt

Edited: 19 July 2003, 12:03 a.m.


Hey Bill,

I think it is really a wonderful thing that this product, made in the 70's--the time of Viet Nam, Israel-Arab Conflict, OPEC Oil Embargo,
Stagflation, Disco, Double-knit Polyester, Toxic Waste, LSD and the Clean Water Act, has lasted so long after so much use!

You left out "Brady Bunch".

It was the time of "Brady Bunch".

I just watched the "Brady Bunch movies" a movie
plus sequel from the 1980's, very sarcastic and cynical. Even the movies made for a good look backwards in the rear view mirror...... according to the movie plot, the Brady's were still wearing their polka dots and flowers and bright polyesters even in the 1980's, except by then all the punk rockers in black leather are giving them the bird.....

It all fits together ... The olden days were better !!




Norm, I don't have a 34C, but I have a 38C. I leave my cell phone sitting next to it. When a txt message comes in it drives the 38C crazy!! It seems to write and run a 38C program!! Honest. Great error sequences.


Everybody knows that old HP calculators are radio stations.

You set up teh calculator to run a program, and then you set it next to an AM band radio. It's very interesting.

We were doing that even back when those units were brand new.

If it goes wacko with a cellphone next to it, that's just showing the reverse susceptibility, something that we
did not try to observe in the olden days.

I would suggest not doing that..... keep the calculator away from the cellphone so not causing the unit to malfunction...... while unlikely, it could cause some sort of permanent silicon damage ("2 disease").

I kind of like the old calculators behaving like radio stations...... "FCC Part 15 sucks!"


Hi, Norm:

Switching the "large" currents of a LED multiplexed display is a good manner to make a lot of electric noise... As you are an analog guru, yu may even be able to calculate the power of such noise. While I consider myself a digital EE, from your same timeframe, I also did a little of analog work certainly of little value (using LM340, CA3140, SN723, etc...)

As the LED current varies with display settings, a PAUSE with a 1 in the x-register and with FIX 0 "sounds" different than a 0 on FIX 9. As students, we used this rather crude technique to signal program status while working on other things. I described this trick in my article "Calculator Memories from Argentina", posted in the Memories Forum. Indeed, the HP41 BEEP was a welcome improvement for such purposes!

While I respect your HP34 fondness (I used a friend's -34 for a while around 1980), my favories are HP25, 41 and 42.



PS: And also thanks a lot for CZ duty protecting all those Woodstocks and Spices out there!!



The static produced by the classic calculators is nothing compared to that produced by early TI calculators such as the SR-51A. I remember testing this on an AM radio, and the TI produced much more static.



I just tried a few of my calculators:

My HP-41CX (built 1988) is clearly audible, you can hear keypresses and programs, and you can also hear it count down to sleep mode (a slowly rising high-pitched noise, which ends when the calc shuts off). Attaching a printer (and using it) changes the noise quality as well.

The HP-48GX (1994) is also clearly audible, although is not as loud as the 41. Individual key presses sound a bit like a cash register or a printing desktop calculator.

I also tried a 1976 TI-30 - the loudest part is the LED display, you can tell the number of digits displayed from the noise level, but calculations (trig functions) have their charcteristic noise, too.

A ~1990 Casio fx5000p has also a clearly audible display driver, the 8-segment part of the display produces an almost clear tone, while the dot-matrix part is rather noisy.

...oh the fun of playing around with calculators :-)



Hello, Ernie;

I tried to send you an e-mail and I received this message:


The original message was received at Sat, 19 Jul 2003 17:02:54 -0300
from [xxx.xxx.xxx.xxx]

----- The following addresses had transient non-fatal errors -----

----- Transcript of session follows -----
451 <kajzero@earthlink.net>... earthlink.net: Name server timeout
Warning: message still undelivered after 4 hours
Will keep trying until message is 5 days old


Should I try to send the message to another e-mail address or simply wait?

Best regards.

Luiz (Brazil)

Edited: 19 July 2003, 8:26 p.m.



The address you used is correct. I thought maybe you had neglected to remove the NOSPAM string, but you did.

I do not have any other email addresses. Try it again, please.


Possibly Related Threads...
Thread Author Replies Views Last Post
  HP-34C Draining battery quickly Bill Crowell 2 496 09-08-2013, 08:30 AM
Last Post: aj04062
  HP-34C Curiosity Matt Agajanian 7 893 08-23-2013, 06:02 PM
Last Post: Stephan Matthys
  HP-34C Emulator BShoring 8 922 03-30-2013, 05:04 PM
Last Post: BShoring
  Looking for PRNG for HP-34C Dave Boyd 3 491 09-22-2012, 07:10 PM
Last Post: Mike T.
  HP-34C Storage Register Arithmetic & Programming Matt Agajanian 14 1,220 05-08-2012, 11:04 AM
Last Post: Matt Agajanian
  A longstanding HP-34C mystery Matt Agajanian 11 1,202 05-03-2012, 02:29 AM
Last Post: Alexander Oestert
  HP 34C display problem james summers 11 1,137 04-05-2012, 06:07 PM
Last Post: james summers
  HP 34C and 67 for Android Vincent Weber 16 1,406 01-24-2012, 11:38 AM
Last Post: Alexander Oestert
  Repairing HP 41C screw posts Fouad M. Kaadou 7 747 09-25-2011, 08:19 PM
Last Post: Randy
  Two new blog posts of interest to members of this forum Steve Leibson 8 804 09-19-2011, 04:38 PM
Last Post: Mark Hardman

Forum Jump: