ubikuberalles' Blog - Old Calculators

RSS Bot · October 10, 2006

I've never really set out to collect old calculators but it turns out that I do indeed have a modest collection of them. I attribute it mostly to my inability to throw things away. However, a couple of the calculators do have some sentimental value to me.

My interest in calculators started in the late 1960's when my sister and I would visit my father's office in downtown Duluth. My dad was (and still is) a CPA and the office he worked at had all sorts of office equipment: typewriters (electric and manual), check imprinters, rubber stamps and, most importantly, adding machines. Pretty much, that's all they did: add or subtract. If you wanted to multiply something in that office, you had to use a slide rule. x_x Not something an 8-year old like myself would want to learn. Nevertheless, I had fun with the adding machines (albeit briefly) partly because they would printout what you did on a strip of paper. Most of the fun was simply pushing the buttons and watching the machine make noise, spin wheels and printout what I entered (I was only 8 or 9 what do you expect? ).

My first glimpse of an electronic calculator wasn't until 1970 or 1971 when my dad bought a Craig 4 function calculator. It was about 4 inches wide, six inches long and nearly 2 inches thick. Numbers were displayed on a red LED display (7 or 8 digits, I think). The calculator buttons were few (something like 16 or 18 buttons) and therefore rather big. My dad would routinely bring it home from work and I loved playing with it. I don't think I did anything useful with it but it was cool seeing a machine silently display the results of the calculations entered into the keypad. The calculator was expensive: about $400 but my dad liked it so much that he bought a second one and used both extensively over the next five or ten years.

I know the Craig had an impression on me as a child since I clearly remember, when I was in the sixth grade, making a crayon drawing of the calculator during the arts and crafts portion of class.

I didn't get my own calculator until 1977 or 1978. Being the math and physics nerd that I was, I needed something with quite a bit of more power and much more capabilities then what my dad had (I was NOT interested in learning how to use a slide rule). After scanning the various mail order catalogs, I found what I wanted and ordered this calculator:

Click here to see my very first calculator.

As you can see, it has all sorts of buttons and a lot of functions. Many of the functions I did not understand until after I went to college. If you look a little closer at the calculator you will notice something:

Click here for a closer look at my first calculator.

It's a Commodore! Commodore made calculators in those days. Pretty good ones too.

I remember showing off my calculator to my friends as soon as I got it. I did impress them but that didn't last long. A week later one of my friends got himself a calculator that not only performed many of the same functions as mine but his calculator was also programmable. I was impressed in a big way and very jealous (however that jealousy was tempered by the fact that I had access to an Altair computer and he didn't).

Sadly, my Commodore calculator broke down about midway through my college career. Later on I took it apart so I could use the keyboard for some poorly defined project that never materialized. Here's a look of the inside of the calculator:

Click here to see the insides of my first calculator.

Really nothing more than a small PCB that connected to the LED display and keyboard via ribbon cables. Here's a closer look at the board:

Click here for a closer look at he insides of my first calculator.

Pretty much just one big chip to do it all with a couple support chips for driving the LED display and the keyboard. There's also a transistor and a diode for the battery charging circuit. Maybe someday, if the main chip still works, I could hook it up again. The LED display is missing and so I'll have to get another one.

Not long before my Commodore bit the dust, I bought a Casio calculator. Although it didn't have nearly as many features as my Commodore, the Casio had a built in clock and I used it as an alarm clock in addition to its calculator functions. It also had an LCD display and didn't need the batteries recharged constantly like my Commodore did (in fact the Casio used watch batteries which I thought was really cool). The Casio also played a lot of different musical tunes (every Christmas, or example, it would play jingle bells) and I thought that was a nice touch.

I don't have any pics of the Casio but I mention it here because it played an important role when I started working at the Signetics plant. I was hired to write a program that generated reports of integrated circuit test data. The program had to calculate the standard deviation of the data and I didn't know how to perform the calculation. I looked up my old college Calculus and engineering books but I couldn't find an algorithm or even a mathmatical formula. It was the owners manual from my Casio that saved the day: it had the formula for not only Standard Deviation but other mathmatical functions I needed at the time.

Although I loved that calculator, I didn't treat it very well. I routinely put the calculator in my back pocket (the Casio was very thin) and, over the years, the calculator bent into the shape of my rear-end and, after a while, the PCB cracked and the calculator stopped working. Fortunately, that didn't happen until after I graduated from college and I didn't rely on it on a daily basis like I used to. Even if it did fail during my college days, it wouldn't have been a disaster since I had a couple backups thanks to a lucky find one day when I was walking my parents dog.

Whenever I took my parents dog out for a walk I went out to the east mesa which was a dumping ground for a lot of cheap and lazy people. Many times this turned out good for me: I used to go to the mesa to find all sorts of electronic parts I needed for my projects. This time, however, I found something that was more than just parts for my projects: several calculators.

I discovered a discarded cloth bag and, when I looked inside, I found this:

A Novus Scientist calculator. (And you thought Novus was just for credit cards). Not a bad find but the shocker of the day was when I dug deeper in the bag and found this:

A TI 59 programmable calculator! I remember, in high school, staring greedily at the brochures for this calculator. It had everything I ever wanted in a calculator: lots of scientific functions, programmability and - coolest of all - a magnetic card reader. The TI 59 couldn't hold very many programs but that was OK because you could use the programs stored on either a magnetic strip or a ROM chip you plugged in the back. The calculator I found had a whole set of cards and a ROM chip with lots of scientific programs (including a Matrix addition and multiplication routine).

Coincidentally my dad bought a TI 59 around the same time I found mine. He also bought an external printer: you just take the battery out of the back and put the printer interface in its place. Although I didn't use my dad's printer very often, I thought it was cool that I could printout results from my calculator.

Remember that programmable calculator my friend bought that upstaged my Commodore calculator? It turns out my friend no longer needed it and he gave it me. Here it is:

Yep, you guessed it, a Commodore!

The slider switch near the top put the Calculator into programmer mode. Put the switch in the middle position and start typing in the buttons. When you wanted to run the program, just slide the switch to the right and press the R/S button below it. The great thing is that this Commodore calculator still works! The original Ni-Cad batteries are gone, of course, but I was able to hook up a 9-volt battery and the calculator worked like a charm. I can't say the same for most of my other old calculators, however.

Even though they are no longer mechanical, my dad still uses adding machines with the paper tape. Here's one he gave me a while ago when he no longer needed it:

As you can see from the dirt on the keys, my dad used this calculator a lot. I took the calculator so I could hook it up to a computer as a cheap printer. That project never materialized and so it just sits in a box with the rest of my old calculators. I recently powered it up and discovered that it doesn't work for very long - the calculator freezes up after a few operations.

Here's a picture of my current calculator:

Another Casio. It isn't much but it gets the job done. I've had it now for ten or even fifteen years. It's really reliable and I only had to replace the batteries twice. That's because it has a solar cell built in and doesn't need the batteries very often. (For some reason I'm suddenly hungry for some pie).

Remember that $400 Craig calculator my dad got back in 1970? Although I don't have that calculator, I do have one pretty much performs the same functions:

I got it free from the United Blood Services (well, I had to donate some plasma to get it). If you push the switch in the upper right, the cover slowly opens to reveal the LCD display:

Well, that's it, my small calculator collection:

Not a very big or impressive collection but it was cool how it took me down memory lane.

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