An old friend powered up after 30 years !!



#2

My late father gave me a HP calculator (The one that later became the 35) in my second year at Wits University in Johannesburg in about '72.

Although I upgraded to many HPs over the years, I never threw it away although the charger and batteries are long gone.

I found it an old box and decided to donate it to the technology cabinet at my son's school museum, but was curious as to whether it would still work.

Over the weekend I made a plug and power supply for 3.75v from USB, and powered it up.

It still works!! - The on/off needs a bit of cleaning and I have to jiggle the switch to make it work, but other than that it does it's old thing.

Brought a tear to my old eyes to think of my parents and what it cost them way back then.

I'll put the power supply in a box, service the switches, do a bit of a write-up and donate it in working order to the museum.

I hope the young men at the school keep it working for another 40 years!!

Edited: 8 Oct 2012, 11:34 a.m.


#3

That's nice to hear! Working 35's with flaky power switches are the norm, so you're in good company. I hope that your 35 sees another 40 years, I'll bet it does. I doubt that USB ports will be around then, better to build an AC mains power supply for it.


#4

Quote:
I doubt that USB ports will be around then (...)
Wow! Did not see that coming... Scary! Truth, indeed... but scary!
X^C

Edited: 8 Oct 2012, 1:05 p.m.

#5

Quote:
That's nice to hear! Working 35's with flaky power switches are the norm, so you're in good company. I hope that your 35 sees another 40 years, I'll bet it does. I doubt that USB ports will be around then, better to build an AC mains power supply for it.
+1. Consumer computing "standards" are not standards for very long.
#6

These days, phones come with a USB wall charger. That means, AC mains input, USB output. Since these things are so ubiquous now and do not depend on something like computer hardware (just an AC socket), I think they'll still be easily obtainable and useable in 40 years. Well, depends on what shape of USB port you need, but same story for the cables with various types of conversions from one shape of port to another.


Edited: 9 Oct 2012, 6:40 p.m.


#7

I agree that there are zillions of AC to USB converters out there now, but 40 years is a long, long time for technology to change in and for things we take for granted to disappear.

40 years ago you could find a turntable or record player in every home in the western world, what percent of homes have one now. How many people will have a land-line based (POTS) telephone in 10 or 20 years. You probably won't even be able to buy an incandescent light bulb in 10 years and they've been around for 130 years. CRT's (in TV's and computer monitors) they're already gone -- well almost I'm still using one for my main monitor.

On the other hand, AC wall outlets are not going anyway for a long time to come. Even if they do get rid of the frequency correction to 60Hz in the US, we'll still have these nominal 60Hz 120VAC (50Hz 220VAC in much of the rest of the world) power outlets in our homes and workplaces.


Edited: 9 Oct 2012, 8:17 p.m.


#8

Quote:
You probably won't even be able to buy an incandescent light bulb in 10 years and they've been around for 130 years.

Interesting that you should say that. They are banned in Europe now. One of the many crazy things we are doing over here to save the planet. Uhm, I mean, to keep people paying in order to receive indulgence.

Quote:
Even if they do get rid of the frequency correction to 60Hz in the US

That is interesting, too. In Germany we have had much higher variations in mains frequency in recent years. This is due to a change in the way power is generated as well as used. More and more solar and wind power is supplied to the grid, and instead of induction motors directly running of the grid there are more and more inverter drives out there.
Maybe we will go that way in the future, too.


#9

I'm all for getting rid of incandescents. I have switched nearly completely to CFLs and LEDs and my electric bill last year was 80% of the average of the previous 5 years ($160 lower). They really do save money on the power bill, and if they last anywhere near as long as claimed, the overall savings will be significant. There is no loss in light quality, either - my wife won't let me get away with that!

I still need to find decent LED floodlights, though. For some reason (some kind of thermal or electrical warmup?), they take a half second or so to turn on after the switch is thrown. Anybody know why?!?!?!?!?! (This is not like the warm up time for CFLs - the LEDs are either full ON or OFF, but they have this obnoxious delay.)


#10

Just reasoning about:

LEDs need low current and low voltage, even the high-gain type. Considering a 120VAC/60Hz source, after rectifying and linearizing (filtering?) we have about 170Vcc. Considering also a small SMPS to convert the 170Vcc to a suitable power source for the LEDs, chances are that the whole circuit needs this 1 second to stabilize.

The new white LEDs use about 3Vcc (3.3Vcc, IIRC), and we'd need about 57 LED's (or about 52 for a 3.3Vcc) connected in series to allow their connection to the 170Vcc without a voltage reduction. Also, in order to protect the LED's, there would be necessary to add some over-voltage, peak/spike suppress components, etc. So, having a small SMPS to do the job would even allow to use less LED's. I have a LED lamp with (edited to correct this data) 30 LED's, being connected to a 220VAC, 60Hz outlet. And it actually takes a brief to lit after being turned on. Cannot say if they are connected in series or parallel, though.

Cheers.

Luiz (Brazil)

Edited: 10 Oct 2012, 12:38 p.m.


#11

I like to listen to AM broadcast radio at night. Such reception is subject to great radio frequency interference (RFI) from any nearby CFL. The new LED lamps also generate some RFI, due no doubt to the power converters they contain.

Incandescent lamps do not pollute the airwaves and thus are an excellent (and really the only) choice where RFI would otherwise be a problem.

#12

CFLs take a couple of minutes to come up to full brightness. I have measured one in our living room with my light meter, and initially it is only at half brightness. I end up turning it on before I need it, to give it time to get up to speed. For something like a hall closet where it's only on for ten seconds at a time, incandescents are appropriate. Also, the oven light can't be LED or CFL, and the whole point of the oven is to produce heat anyway, so it makes sense to have an incandescent there. I don't know if that's true of the light in the clothes dryer.

But a 20% savings was $160?? So the whole bill is $800?? We have at least three computers and two aquarium pumps running 24*7, an aquarium light running all day every day, electric stove and oven, and the total electric bill is about $60, with several incandescent bulbs. BTW, when we replaced our 30-year-old refrigerator with an Energy Star one, our bill actually went up, not down, and then I read of corruption in the agency that gives the ratings. When I checked the wattage on the refrigerator label, yep, the new one takes more. It's the same size as the old one, and needed repair in the first year.


#13

In case it was not clear, the $800 was my total annual. So, my new monthly is comparable to yours ($45-$60 depending on season - in the winter we pump hot water through the floor for heating).

#14

If most of your electricity is used for lighting, then yes, you can save a significant amount.
I also have CFLs in some places. But in others it simply does not make sense.
But why BAN the incandescent bulbs? With the cost of energy going up, people make their own choices.

I have stocked up on incandescent bulbs, so I can still use them if I want to. In my opinion they are still the better and cheaper option for a lot of uses.

#15

Quote:
(The one that later became the 35)

Can you elaborate on this? Is it a prototype of the 35? Or something else?

#16

I read this as just a reference to the label on front of the calculator that changed from "HEWLETT PACKARD" to "HEWLETT PACKARD 35".


#17

The "35" designation was only added after the calculator had been in production for a few months. Before that it was simply the "Hewlett Packard" calculator.

This one is one of the "made in Singapore" ones. As far as I remember there were also Mexican ones marketed in South Africa

Unfortunately the sticker from the front as well as the back sticker have gone.

You are right about the USB interface - will not be lazy and will make a 220v one.

This calculator will probably outlive USB technology.


#18

This is a draft of the blurb for the display cabinet at the school - Would appreciate a "proof read" from you experts:-

---
The Hewlett Packard Pocket Scientific Calculator
History
The Hewlett Packard Pocket Calculator was one of the most important developments in calculator technology. Prior to its introduction in 1972 Engineers, Scientists and mathematicians used 7-figure log books, slide rules and later bulky desktop calculators to get answers to their complex calculations. This calculator proved it was possible to pack that capability into a shirt pocket, or actually William Hewlett’s shirt pocket.
In 1970 the co-founder of Hewlett Packard, William Hewlett, challenged his engineers to make a calculator that would fit into his shirt pocket, even though although research at the time revealed no market for such a device. A few prototypes we built and they soon became a “must have” among the HP engineers and scientists.
The calculator was introduced to market in 1972 at a price of $395, and 100 000 were sold in the first year and 300 000 by the end of production in 1975. The model number “35” – it had 35 keys - was added to the name when it became clear there was a huge market for scientific calculators and HP started work on its many successors.
The calculator was built around a custom designed Mostek serial – one bit – processor which stored 14 digit numbers in a 56 bit floating point format.
One of the biggest challenges the designers faced in ’72 was the display. The 35 displayed numbers as a signed 10 digit mantissa and a signed two-digit exponent giving a 200 decade range on a 15 digit display. Battery life from three AA sized rechargeable batteries was between three to four hours, and as a result the most common failure was the on-off switch.
The calculator used Reverse Polish Notation (RPN) with a dynamic four register stack and a single extra register. Note the calculator has no parentheses or “=” buttons
To compute:-
√((Sin⁡(34*1.25)+Cos⁡(54))/(e^3.2+Ln⁡(45) )) = 0.21
Keystrokes:-
34 [Enter]1.25 [x][sin] 54 [cos][+] 3.2 [ex] 45 [ln][+][÷][√x]

In 2007, to mark the 35th anniversary of the HP35, Hewlett Packard introduced the HP 35s
This Calculator
This HP was bought for Peter Charter (Baines ’69) as a Mining Engineering student of average mathematical ability, but well below average arithmetic capability in 1972. Peter claims he would never have passed Survey I without it!! It saw extensive service on and in various gold and platinum mines, and took an excursion into Angola in an army rucksack in ’75.
Peter found it in an old box in 2012 – the battery pack and power supply had long gone – fashioned the plug and USB power supply, cleaned the on-off switch and powered it up.
It was donated to the school in 2012. Peter currently has three HP calculators in daily use – one of which is a 35s.

Edited: 21 Oct 2012, 2:40 a.m.


#19

If I may... I added some bold markings to call your attention to what I am not sure about, but it does not mean it should be changed.

Quote:
--- The Hewlett Packard Pocket Scientific Calculator History The Hewlett Packard Pocket Calculator was one (...) The HP35 displayed numbers as a signed 10 digit mantissa and a signed two-digit exponent giving a 200 decade range on a 15 digit display. (...) To compute:- √((Sin⁡(34*1.25)+Cos⁡(54))/(e^3.2+Ln⁡(45) )) = 0.21 Keystrokes:- 34 [Enter]1.25 [x][sin] 54 [cos][+] 3.2 [ex] 45 [ln][+][÷][√x](there are some extra codes added after copy and paste, I guess.)

In 2007, to mark the 35th anniversary of the HP35, Hewlett Packard introduced the HP 35s. This Calculator This HP (does it refer to the HP35 or the HP35S?) was bought for Peter Charter (Baines ’69) (...) Peter found it (what about 'its old HP35'?) in an old box in 2012 (...) Peter currently has three HP calculators in daily use – one of which is a 35s.


Hope it has been of any help.

Luiz (Brazil)


Edited: 21 Oct 2012, 4:51 a.m.


#20

Good points - noted.

Muito obregado O Senhor

#21

Quote:
... used 7-figure log books, slide rules and later bulky desktop calculators to get answers to their complex calculations

Slide rules and 7-figure log tables are in a much different league!

This, of course, refers to either quick calculations or when you were away from your main frame computer - which was where you really did your "complex calculations" in 1972.


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