Thermo1, That's the one that first used a filament lamp to reduce distortion, isn't it? Those were the good old days but unfortunately, somewhat before my time.

Some of the HP on my shelf are 3336B, E3610A, 6181C, 400FL, 204D, 4437A and others.

For scopes, I will not have an HP, not then, not now, probably not ever. Tek reigns supreme in scopes (to a point in the GHz where others take over).

At one time I had an HP Eput Meter which actually predated nixie tubes. It had vertical rows of NE2 neon bulbs behind number overlays. At the time, thought it would make a great boat anchor ... actually it still probably would but if it had nixies, that would be different

HP 32SII was the ultimate calculator; no graphing, just a 10 digit display with well placed keys, and of course very rugged. I dropped mine two stories onto concrete and it still worked despite being slightly bent.

When I heard HP stopped making them I ran to Microcenter and bought the four remaining in stock for $50 each. They soon soared to over $300 on ebay. I should have enough on hand to last me the rest of my life.

I'd like to build the ultimate calculator though. It would be a "hardened" 32SII with a titanium case, waterproof keypad, and a quartz display cover.

I could use a low power FPGA or micro-controller and then machine my own case.

060314-2045 EST USA

dennh:

The HP RC phase shift oscillator used the the tungsten filament lamp as a voltage regulator. This was part of the feedback loop. The output voltage was reasonably stable from minimum to maximum frequency. The filament was run at a very low color temperature. It is a long time since I looked inside the 200CD.

A. D. Moore, one of my professors in a senior class had a standard question --- what is the maximum phase shift in an RC network? The majority of the students would answer 90 deg. If that was so the HP oscillator would not work. I believe HP used four, possibly it was three, ganged air variable capacitors in a multi-stage RC network to achieve 180 deg phase shift at the oscillator frequency, and another 180 in the amplifier.

The RC oscillator is what created the HP company.

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In the 60's, Heathkit (anybody remembr them) made a greatly simplified version of that general design, with light bulbs as non-linear resistors. It had very low distortion, and I still have it somewhere. But, the parts were not anywhere near the quality of hp test gear, and Heathkit failed during some tests I was running. Had to replace the whole range switch.

I got my hp 200cd at a surplus store in Cambridge, I still have that but, don't use it. I also have a E1301A data logger for some work a number of years ago on measuring building system performance. It was a bit more than I really needed, but I was tired of buying equipment that became inadequate to my needs. You really appreciate good test gear when you use it out in the field.

As far as scopes go, David Packard's memoirs has a section about scopes, and how he tried to hire the founder of Techtronics, and without him, it took hp a long while to make a good scope.

After the Board fired Carly whatshername, there was an article on the Op-Ed page of the Wall Street Journal, giving advice to the new president of hp. One of the suggestions was to buy back Agilent, as that really was the soul of the company.

Thermo1

I used to have one of the FIRST HP oscillators. NOT the 200CD, one of which I still have. I forget the model number now, it was a boxy item with the dial in the middle.

And, I had one of the EARLY tunable voltmeters, complete with 1943 typed manual. But I needed the space, and sold them.

The 200CD also DOES use light bulbs to stabilize, btw. And those bulbs aren't very easy to find.

Still have a bunch of 330s, and a 334, being that I have been in the audio biz for years.

But, HP NEVER got it right with scopes. They all stank. Nothing like a Tek.

The 41CV was the perfect animal though. I even had a circuit analysis program for it.... Its carcass is somewhere, probably not all in one place now.

Oh my god, just looked at ebay. Don't think I'll be getting one soon. Damn.

I've been meaning to find one of the older HP's for work. Used to use a 15 I believe at my first drafting job. This thread reminded me about needing to find one, and as mentioned, a quick look at ebay has left me gasping.

I might start spending my weekends checking garage sales for these things; rigging can't be nearly as bad as a big metal shaper.

And why do I want one? RPN of course; we're always "calculator poor" at work, and I know I'm the only one that could run it. If they can't use it, maybe they'll quit taking my damn calculator.

Better stop screwing around and go put the gearbox on the Monarch.

Although if any of you guys with multiples are feeling kindly and have run out of space to store them I'd be interested in a good deal...

Rob

My first RPN calculator, around 1975, was an HP25. I was a new math teacher then, and to me, the = sign “true algebraic notation” marketing hype calculators sucked. I’m happy to say that many of my students agreed. That calculator disappeared after I put it on the car roof while unlocking the car door, forgot about it and drove away.

I bought the next model, an HP29C, as I recall. It worked great, but shortly after the warranty expired it died. HP wanted about $75 to fix it. I was very disappointed, and did not deal with HP again.

Bought another RPN from some company whose name escapes me – it didn’t last, and neither did the company.

I did not go back to HP (high prices, and poor experience). As soon as RPN became available on the net, I’ve used that.

Reminds me of Beta vs VHS. The great unwashed, fuelled by advertising, preferred VHS, while professionals continued with Beta.

I see on this thread that a number of you have had a good experience with some HP RPN calculators. Perhaps I’ll give them another try, 30 years later.

I have 5 or 6 200cd oscillators sitting around and a few similiar but not the same model. Remember the 410b voltmeter? It has a tube diode in the AC probe. I was a electronics surplus junky for a number of years and have stuff running out of my ears. One thing I remember about HP is that I have never seen a damaged meter movement from normal use. I can't say that about other brands.

060315-0836 EST USA

If you go to my www.beta-aa.com web site and the page on miscellaneous photos the last picture is of N. P. Psytar. Here you see a number of 200CD oscillators, two HP voltmeters, and a General Radio noise generator.

N. P. Pystar was used by Dr. Wilson P. Tanner for fundemental work on human signal detectability. This work was supported by the US Army Signal Corp.

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heck, I am looking at a 410BR right now... And I have the probe & tube.....

I know what you mean about HP on the bay.... sheesh.

I have 5 or 6 200cd oscillators sitting around and a few similiar but not the same model.

Gee, you could do a remake of Disney's Fantasia with that many 200CDs

For those of you who miss the the HP41 calculators I have just listed a 41cv and a 41cx on ebay. Please click the links to see the listings

So since PM is the place I heard about RPN many years ago and I had bought last fall a HP-35S, I currently bought off Ebay a HP-41CV from Ebay, and I figured I'd mention it here.

Hewlett Packard HP 41CV HP-41CV 9.5/10 condition! - eBay (item 280462429141 end time Feb-07-10 18:33:20 PST)

Now to reverse engineer it once it comes in and my HP Museum DVD comes as well, that way I can see if I can rig something up running a Atmel AVR microcontroller (I've been working on a RPN calculator on the AVR, but figure I could clone the HP-41 and scrap the original project). Even if the project is not successful.

Dimitri

I've had a HP-41CX since 1981 with card reader, printer, and optical wand for writing your own bar code programs.
I've used this every day since purchased. I still use it today.
The best calcualtor out there. Could not live without RPN.

Another testimonial from a long time HP devotee. A friend of my dads's showed me his new HP 35 and then 65 calculators, and they made a huge impression on me. My first HP was a 25C and I learned to use and program that thing to its limits. I was in college when the 41C came out and had to have one. I loved that calculator. It died after a fall on the floor a few years ago. I limped by with a free HP 11, 12, 15, 16 emulator on my (jailbroken) iPhone for a while, but that went toes-up when I moved to version 3 of the phone software. There are lots of RPN options in Apple store, but if I'm going to shell out I think I'd rather have the real thing. A generous friend gave me an HP 65, which is a still a pretty nice calculator.

This was the first scientific calculator I purchased many years ago I used it until it fell apart.



In my humble opinion Ti makes the best calculators.

Marci

An HP 25 got me through school and once I got going in the real world I graduated to a HP 12C.
I need the financial features of the 12C and if I need to do the fancy stuff Autocad will normally handle it.

Have to agree on the TEK scopes also. I repaired and calibrated test equipment in the Navy.
The HP stuff was rugged and worked fine but the technical superiority of the Tektronix scopes was obvious.
My favorite unit was the original HP 524A counter, a 2 ft cube that weighed in at 3.4 tons (approx) with meters for the 2 least significant digits.

Have you looked at the i41CX+ HP-41CX emulator for the iPhone? Seems to have gotten a wad of good reviews from HP fans. I've also noticed MathU RPN as I've been looking for an RPN calculator to add to my iPod Touch. I think both are compatible with OS 3.

--Larry

I have a HP11C that I bought in 1984 and it is still working great. I also have 2 HP48G's and a HP48GX that I have been using since 1991.

I told my wife that if she would ever learn RPN, she would never go back to a algabraic calculator. She now carries a HP12C in her purse.

One thing I REALLY like about the HP RPN is it keeps everyone in the shop from wanting to borrow your calculator.

My son once bought a Texas Instruments scientific calculator and he wanted to check it out against my HP's. We solved an angle 3 different times and got 3 different results. My HP was right on the monet every time.

HP's might cost a little more, but they are like a Timex watch. They take a licking and keep on working.

Hi guys.

I'm proud and happy owner of a 15C, which I bought to replace a Ti58.

The Ti's were very much in use then I was an engineering student, but
the buttons were lousy and the NiCd's ran low fast. So when we had exams,
everybody were fighting over the power outlets.

Then the HP15C arrived and I haven't looked back since. Now I am a teacher
at our local trade school, and I still have it - at least 25 years later. The battery
cells has been changed once, about 3 or 4 years ago. Since I bought that
calculator I haven't used any other. I have the new Texas 30 since my students
have to buy it, but I use it only to teach my students how to use theirs. I always
use my own and I'll keep on using it until it fails. Then I'll hunt the world to find
another like it! (hmm, I had better start now)

RPN is the most effective way for me with the four-layer stack.
The buttons are hinged and precise.
It uses almost no power - the battery cells last forever.

Cheers
Erik