LED Calculators... do you collect them?

[xevious]

I've heard that there are a few really rare LED calculators from the distant past fetching some handsome prices these days. I think a couple models of Texas Instruments and Hewlett Packard make up a portion of the "most wanted" list. Unfortunately, the source I read was a while back and I can't remember where I saw it on-line.

Anyway, I don't collect them but I do know that I've got a couple of LED calculators packed away in a storage box deep in the attic... one great old Casio with bright blue LED's and a very nifty HP with RPN notation. The Casio works only on the AC adapter--haven't figured out yet why not on the batteries. The HP batteries long ago disintegrated. I'm going to have to hunt down some modern day replacements. I'll have to do some digging around and see if I can locate them, take some photos, post 'em up for show, etc.

Anyone here have some cool LED calculators still serviceable?

[rewolf]

... Unfortunately, the source I read was a while back and I can't remember where I saw it on-line....

Could it have been here: http://www.vintagecalculators.com/? Very nice site to browse
As for your "blue" Casio: it's quite probably a VFD (Vacuum Flourescent Display). Vintagecalculators also gives a nice overview of display technology IIRC.
I hope you can reanimate your old calculators.

I don't actually collect calculators, but have some memories:

My first pocket calculator (1980) was a Privileg 585-DE. It had a green VFD and ran only 4 hrs on 2 AA batteries, so I had to pay 50% of the calculator's price for an AC adapter. I loved that green glow at night.
The next calculator was the Casio fx-100 we used at school. I "tuned" it to run 3 times faster (simply replace oscillator resistor). But that made it shut down after 1.5 minutes (instead of 5), so I had to add a little circuit (4 CMOS-ICs 40xx) to "press" an unused key shortly before it would shut down to defeat the auto-power-off feature. The circuit was in the 2xAA battery case, so I replaced the battery with 1xCR2032. I still have it.
Then came others:
Casio fx-501P (my first programmable, I always loved that yellowish LCD)
Casio fx-451 (hexadecimal and binary logic functions, unit conversion)
Casio fx-7000G (my first graphics LCD)
Casio fx-8000G (doesn't work any more).
Currently I'm using a Casio fx-3650P.

[Diginut]

Me !

I have maybe 700+ digital watches, about 30 of which are seriously unusual LED and LCD calculator watches with only one particular rarity missing.

Plus I have maybe 45/50 calculators from 1973 onwards, mostly LED, some DSM, and a few LCD. But none much later than about 1978. And maybe 6 or 7 Nixie tube 16 digit calcs.

My very first ever calculator was given to me by my dad in 1973. It was a Sharp Elsimate EL122. Had 4 simple functions, green VFD display, and glowed in the dark nicely. But whilst it displayed 6 digits at a time, you realy had 12, and toggled the display with the <--> key (see image). Another unusual thing was that the digits were justified to the left, moving across to the right as you entered more. Weird.

My 2nd calculator was a TI SR 56 programmable in 1976. This single event shaped my career as a computer hardware/software person later in life. I got it in Hong Kong, and used it in my 1978 high school exams as calcs were allowed that year. But no school examiner noticed it had more than 4 functions or even suspected a kid would have a thing called a "programmable calc" ...

And the best bit is ... I still own both of them and they still work. In fact the 1973 Sharp is sitting in my desk as I type. It freaks everybody out when I tell them I had it at school 35 years ago !!!!!! (before most of my colleagues were born ...)

"Xevious" ... I know all about this game, becuase ... I used to work at Atari in 1983/4 !

Anyway, heres a pic to prove my point !!!

[rewolf]

I'm more and more attracted by these LED calculators. Have to start looking for a nice TI calc (the HPs are also nice, but I'm too stupid for RPN ). The more digits the better
Can anybody tell how much current they consume (in mA) so I can estimate battery life?

[Diginut]

I've never actually measured the current drain on the TI.

It had a rechargable battery pack, Nicads etc, and I can remember it running down in a couple of hours of continuous use. But if you turned it off, you lost your program, and I do remember always being paranoid about the battering blinking out. In school exams we couldnt use a mains socket to plug the charger into.

Later TI's, like the amazing TI 59 had a magnetic strip reader / writer, and you could save things in/out quickly, as well as tiny ROM packs with major function libraries, and various alpha numeric printers, and I think also I/O boxes to control stuff. Its hard to beleive today that back in 1977 you could feed a small strip of magentic card (1cm x 5cm) into the calc, and it would draw it in and read off the program, like some james bond gadget making all sorts of tiny whirrs and buzzes.

One thing to be wary of if you are buying one off ebay, is that the old Nicads will commit suicide after so many years, and when they blow their brains out all over the inside you will have one dead calculator. So be wary about buying one thats says 'used to work, but needs a new battery' and all that bollox.

I've replaced my nicads with an ordinary AA battery pack and it still works fine in 2008.


As per usual with the interweb, theres stacks of info, and even dedicated websites, just for the TI59.

http://www.ti59.com/history.htm

http://www.ti59.com/gallery.htm

[rewolf]

Ok, it has started )
I want lots of digits, scientific functions, a simple clean look, some historic relevance. Programmability no required (have other calculators for that).
The TI SR-50 has it all (first TI with trigonometric functions, last with clean front panel).

So I shot 2 SR-50 on ebay last night, "untested" and no AC adaptor (couldn't use an US adaptor anyway) but in good cosmetic condition.
Let's see what I will receive for altogether 20$...

I plan to make this my desktop calculator, supplied via USB (I hope my PC delivers more than 100mA to a non-configured device...) and primary AAs as backup. Will quite probably need a little circuit modification, but not more than 2 or 3 diodes

[xevious]

Congrats on the score, Rewolf. Your USB powered calculator project sounds quite interesting--I'll be eagerly watching for progress reports!

[TheFordGuy]

I really don't have a collection, but I have one LED calculator that I use at work every day. It's a Texas Instruments TI-1250, just a basic 8-digit calculator that gets the job done. Runs on one 9-volt battery or an AC adaptor. It's much better quality than the cheap LCD calculators and adds a bit of a "retro" look to my desk.

My mom bought it brand new back in about 1975 or so, and it sat in the drawer for probably about 20 of those years. Her eyesight was getting bad enough that she couldn't see the small digits well anymore, so she got a big-digit LCD and has been using that ever since. Since it wasn't dong anything, I asked if I could have it. It now has a new home on my desk at work.

[redled]

I do. I have probably 400 calculators and 100 LED watches. Basically the same technology in a different application. Both fun to collect and a part of the same era.

Hewlett Packard is like the Pulsar of calculators. The situation is almost identical. though I think with calculators the market was bigger and the market forces were even more intense. The HP35 was as much a revolution as was the first Pulsar,and just like Pulsar HP set the standard of quality and reputation, and today HP and Pulsar are both at the top as far as collectors go. [/i]

[rewolf]

Ok some time has passed since my last posting in this thread, and many calculators have reached my home

Here's the story:

The SR-50 did no meet my needs. Lack of paranetheses and only one memory: try (a+b) / (c+d) without using the memory.
So I headed for the SR-56 - now I've got a super nice one for everyday use at work

Then of course I needed the calculators "between" the SR-56 and the SR-50, namely the SR-51, SR-50A, SR-51A
Next, the SR-50A and SR-51A exist in 2 internally totally different versions - and as a serious collector you oviously need both
The SR-50 also exists with 2 different ROM versions, as well as the SR-56 (its first version has a bug).
Last but not least, you need the link between the LED and LCD calculators, the TI-66.
And as we all know, it often takes several examples of an item until to get a perfect one (or make it out of the others).
And sometimes calculators come in lots and you get more than you actually want (for less money, surprisingly).
Not to forget the accessories: pouch, charger, box, manuals, battery packs....

Luckily, TI calculators are very cheap and quite easy to obtain
Except for this one:


IMHO, the 2nd generation (SR-50A/51A/56) is the best. Well constructed and solid. They can cope with HPs in this regard.
The 1st generation (SR-50/51) suffers mainly from its poor on/off and D/R switches, and the case is not as solid (the case halves are not directly screwed together).
BTW I have not experienced any bouncing keys so far any any of them.
The last LED generation (TI-30 etc, "Majestic Line") is poorly made - I guess these are the ones that ruined TI's reputation among collectors.

Here's a quick shot of 3 calculators side by side:

BTW: The HP 35s was a big disappointment (no, RPN is NOT the problem ). It looks beautiful, but has enough annoying "features" to put me off - e.g. look closely at the display: it's trying to show "-1.234567898E-12", and you have to scroll (!!) to see the full exponent - EVERY 30 year old scientific calculator can do this better.
Programs run terribly slow - my 20 year old Casio fx-8000 (resurrected) runs 10 times faster, doesn't consume more current and has a graphic LCD.
The base-n (hex/oct) etc modes are practically unusable.
So the HP-35s is merely collecting dust. From time to time I take a sad look at it and think what a beautiful machine it almost is .

[Diginut]

Wow - rewolf - someone else likes the SR-56 32 yrs on ! How cool is that ?!

I have a number of really ancient 70's calculators on my desk, and use them variously throughout the day. Plus I wear a classic LED watch most of the time.

But I employ many people who'd now be called 'geek' programmers who are typically dead confident with themselves etc etc but are often only 25 yrs old. These calculators are often 10 yrs OLDER than them and they just cant get their head around the fact a LED calculator existed that far ago before they were a twinkle in their dads eye ...

... and a solid gold pulsar calculator watch is all it needs to finish them off completely !

[rewolf]

Recently I took the SR-56 to the EMC lab. The guy that runs the lab (age ~45) spotted it and called out "hey, coll, you have an SR-56 - I used to have an SR-50A". We talked a bit about these calculators. His assistant (~30) looked like he wasn't quite sure what to think about it

I even use the SR-56 with in technical meetings with customers. Of course I always take care the batteries are fully charged... 4-5hrs operation time with a 3,6V 750mAh NiCd pack :|.

A 2100mAh LiIon battery pack is already built, but not yet the charging and protection circuit (inside the calculator), so I don't dare use it because once I forget to switch the calculator off it will deep-discharge and ruin the battery. Charging source will be USB compatible (5V, max. 500mA), so it will operate and charge on a USB port or any cheap "USB charger" (5.0V wall adaptor).

[Diginut]

Recently I took the SR-56 to the EMC lab. The guy that runs the lab (age ~45) spotted it and called out "hey, coll, you have an SR-56 - I used to have an SR-50A". We talked a bit about these calculators. His assistant (~30) looked like he wasn't quite sure what to think about it

I even use the SR-56 with in technical meetings with customers. Of course I always take care the batteries are fully charged... 4-5hrs operation time with a 3,6V 750mAh NiCd pack :|.

A 2100mAh LiIon battery pack is already built, but not yet the charging and protection circuit (inside the calculator), so I don't dare use it because once I forget to switch the calculator off it will deep-discharge and ruin the battery. Charging source will be USB compatible (5V, max. 500mA), so it will operate and charge on a USB port or any cheap "USB charger" (5.0V wall adaptor).

Just curious - did you ever build in Lithium Ion battery / USB charge/prot circuit ?

Id be very keen to know the schematics if you did, as I'd have a ball using my SR-56 again, at work, running off the PC when needed ...

some of the younger crew dont know what to make of it. Some think its like a really advanced modern retro tech geek gadget from T3 magazine, others just think its an old calculator with "red LCD lights" (!!!!) made before they were born .....

sheesh ... I'm begining to sound old. Maybe I should grow a beard and start smoking backy in a fat pipe or sumthin.

[635 nm.]

I collect a few, one of my favorites is a LLoyds that uses the first LCD display for a consumer device. The big drawback is it is big and heavy because it used 4 "D" size cells to run one 6 volt filiment type lamp. I went through 3 of them before I found one that had all segments working. Collectingcalculators.com has the info. Another one is the first one to sell for less than $100.00 US. called the RapidMan, it too still works, but sucks 9 volt batteries dry. Another nice one is by Canon, 10 digits, battery level meter. Called the Palmtronic LE-10.
All The Best!
Richard

[rewolf]

Just curious - did you ever build in Lithium Ion battery / USB charge/prot circuit ?
Id be very keen to know the schematics if you did, as I'd have a ball using my SR-56 again, at work, running off the PC when needed ...

No, been much too busy at work in the last months to do a little private side-project...
Though I'm using the SR-56 as every-day calculator at work, with a NiCd battery pack (not the LiIon pack), I need to charge it only every 3-4 weeks
So there isn't much pressure to finish the project...
I have a hand-drawn draft of the circuit. It uses a MAX8606 charger IC and a MAX6430 voltage supervisor with external FET to prevent deep-discharge (important because the calculator keeps sucking high current even at less than 1V battery voltage though it stops working below 2.4V). And a "prototype" cardboard "PCB" to see how it fits into the calculator.

[Snetzka]

Here's an Texas Instruments SR-11 I have sat on my work bench. It uses descret LED displays as used in the early Synchronar models..

[Steamerpoint]

I used to also own a TI SR-56 during my secondary school education, but I guess it must have died as I havent seen it since I left home.

Just spotted Rewolf's Casio Super FX. I have A Super-FX 85v, which lives on my desk and I use daily. Inside the box, under the calculator lives the original guarantee and the argos receipt when I bought it in 1992. Okay, not exactly an antique, but give it another 14 years and it will be, so worth while keeping it all together!

[rewolf]

Here's an Texas Instruments SR-11 I have sat on my work bench. It uses descret LED displays as used in the early Synchronar models..

Like these?

SR-10 LED display with lens:


SR-10 LED super hires picture, you can see the LED chip structures - note the differently angled decimal dots!


SR-10 LED display rear side - neat solderwork


SR-51 (sorry for the blur...)



SR-56, the last TI LED calculator to use a 14-digit LED module



Enjoy

[rewolf]

...I have A Super-FX 85v, which lives on my desk and I use daily. Inside the box, under the calculator lives the original guarantee and the argos receipt when I bought it in 1992

IMO, the calculator series your super FX belongs to was the best-looking Casio ever made. I like the clean body shape and aluminium keyplate.


Talking about aluminium - my favourite TI LCD calculator, the wonderful TI-66 PROGRAMMBLE:

BTW this one runs 2.5 times faster than normal (=just as "fast" as an SR-56) due to this little modification:

Current consumption and auto-off-time remain unaffected by the modification
I have 2 and would part with the pictured one

And talking about programmables - the TI-74 BASICALC is a very nice machine too (it features an an aluminium display frame)

[bucko170]

I just have this Texas Instrument calculator.

I am practicing different methods of uploading and posting pictures, thought I may as well post the picture.

[Steamerpoint]

IMO, the calculator series your super FX belongs to was the best-looking Casio ever made. I like the clean body shape and aluminium keyplate.

That's nice of you to say. I nearly never took a photo of it thinking that a 16 year old calculator is not old enough to grace the pages of this site, but hey I'm just glad someone appreciated it.
At thie time I just needed a decent quality scientific calculator. It has been a great little workhorse, but I am embarrased to say that half the functions have never been tried and tested because I have no idea what half of them do or mean!

[rewolf]

I just have this Texas Instrument calculator.

Nice - TI didn't make many VFD models. And it has an aluminium keyplate
I'm currently trying hard to keep to DSM-LCD, 14-digit LED and early FE-LCD programmble calculators. I fear if I start with VFD, things will get out of control...