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Full Name (family, given): Rasmussen, Johnny Bjoern
Location: Denmark
Entered: 27 Apr 2004, 2:56 a.m.

My calculator nerdiness

About 1978:

Pocket calculators have always appealed to my curiosity. The first pocket calculator that i remember, was a Texas Instruments TI-1200, that my father bought in Lemvig some time around 1976. [Picture of TI-1200] (ask if you may use the picture with permission) It had the four basic functions (+ - × ÷) and equipped with a 8-digit 7-segment red LED-display. We all experimented with the calculator to see what it could do. Being only about 10 years, I was most amazed by the flashing "88888888" when the calculator showed overflow. The keyboard was rather hard and made a loud audible "click" when pushed. Shotly here after my uncle Erik bought a pocket calculator in black finish with green floucent display.

Around 1983

At this time the keyboard on the TI-1200 had been bouncing for a while. When pressing a key, you often got two or three times the pressed function. My father who was the most frequent user of the TI-1200 got tiered of it, and I inherited the calculator for scrap, and didn't hesitate to use a screwdriver on it, wanting to have a look inside it.

I expected to find a lot of electronics inside, but as far as I remember, there was only one IC, a few resistors, capacitors and the display panel, and the battery connector. The display was the most interesting part to me. Each segment in the 8 digits was constructed by a number of tiny LEDs, placed directly on the circuit board.

Each segment (3-4 LEDs) had a common resistor and was connected to the main (and only) IC via golden web-thin wires. Being a complete rookie in electronics at the time, I had fun sliding a metal object from one end to the other of the golden threads, watching the fireworks on the display "Hmmm - interesting" I thought... I was also surprised I was to find some "hidden" keys under the metal font. I could only figure the function of one of these buttons, namely the [+/-]. I didn't know until lately, what the other three buttons was for; M+, M÷, MRC. Hmmm - no wonder that I couldn't se any changes in the display, pressing these buttons. I remember that I wondered why these keys were not in use, but thought that it probably was for a more expensive calculator. This assumption was right, as I learned much later, in a description of old Texas Calculators.

I dissoldered the IC, hoping that I could use it later in a home-made project. Showing him the IC from the TI-1200, my teacher, Joern Hanghoej, in the electronics class in my school Thyboroen Skole, said that it could be used for calculations (In Danish: "Den her, den kan regn', Johnny... Den ka'... Den ka'... Den ka'...").

Today I know that Texas Instruments used the same IC in several calculator models. The TI-1200 was the basic calculator in the 1200-series.

Around 1983

I am 15 years old: I buy my first programmable calculator: a Texas Instruments TI Programmable 57. I was in the main town of the area, called Lemvig, travelling by bus. My little brother Allan and my mother were also on the trip. I bought it at Lemvig Papirforretning and paid kr. 795,- for it (about $ 68). The store also had a more expensive model, the TI-59. I don't remember the price of this calculator, but I seem to recall that it was about $35 more than the TI-57. Not having the extra money for the TI-59, I still was fascinated by the "Solid State Memory" pressed on the front, bragging that it had constant memory. The store also had the printer for the TI-59. Being many years ago now, I was surprised to know that the salesman who sold me the TI-57 in 1983 still remembered me, buying the calculator, as I today regulary talk to him.

Of cause the TI-57 I had was the first generation with red LED display. Having spent all my savings, I already had entered the first program, from the manual, in a nearby Café, before catching the bus home.

I was still in the eighth grade in Thyboroen Skole, and I guess, considered as some kind of nerd, spending the money on a electronic calculator, that my class mated spent on clothes and music records. About the same time I bought my Sinclair ZX-81 at Lemvig Foto. The price was kr. 1195,- (some $90). I had been looking at it a number of times, and have had it demonstrated by the salesman in the store. The morning I went by bus to Lemvig to buy it, the female salesperson from the store also was on the bus from Thyboroen - apparently she was the girlfriend of a technician working at Thyborøn Skibsradio.

That day the male salesman was not in the store, so the female salesperson asked with a kind of worried voice, if I was completely sure of what I was buying, as if she felt a kind of responsibillity for me spending all my savings on this so called 'datamat'. I answered, that I had read a lot about the computer and already knew quite a lot about it's Basic language. Also I remember, that some strange looking new computer was appearing on the shelf in the store that day. Later on I learned that it was the Oric-1 - another Basic language computer of many that almost invaded the stores at the time.

When I got home, "The Television War" started. I guess this "war" was played many places, besides at our home. For me, the thing was to convince my mother, that there was absolutly nothing on the television each night. Then I could use the television, a Salora 26", as monitor for my Zx-81.

Well - soon I got fet up, sitting on the floor 1½ meters in front of the television, wich, not by coincidence, responds to the exact length of signal cable connecting the computer and TV. BC Electronic had a nice yellow finished Sanyo 12" black and white TV for about $90 (kr. 1700,-) that I really wanted. Not having all the money, my brother Rudi borrowed me the missing amount, so the day of the delivery was a happy day. But before that, I made a 5 meter RF-extension cable, so I could sit at the coffey table typing along on the membrane keybard.

One day my electronics class teacher Joern Hanghoej persuaded me into bringing this 'State Of The Art' new piece of high technology to the school, so all interested could se what all the fuzz was about. We set it up in a special room next to the gym. I don't remember how big the showup was, but it ended in talk about the ZX-81 and the new computers in miscellanious magazines eg. NewBrain, ZX-Spectrum, MiroBee, Lynx, etc, etc... If I remember correct, we held a couple of this sessions. One could call it computer parties...

I sold the TI-57 to Svend, an older school mate from my electronics class (Resently my parents picked the very same calculator up in a secondhand store back home in Thyboroen!).

I spent the money as a part of the amount of my new calculator; a Casio PB-100 Personal Computer. This was while I worked at Kristians Radio after school. I think the price were around $85 (kr. 1000,-).

About 1984

I made a lot of small programmes on my PB-100, and also used it as calculator. One of my colleges at Kristians Radio had a Casio FX-602P Programmable Calculator that I thought was interesting. We traded mashines. I keept it and had a FP-10 printer and a FA-2 tapeinterface along with it.

Then it happened:

I got hit by the HP-calculator fever: I talked to my brother Rudi on the phone. He told me that he had bought a Hewlett-Packard HP-41C. He told me a lot about it, and that made me rush to the library to search for information about it. I only found one article about the HP-41 in a Danish magazine called "HI-FI & Elektronik". Further on Rudi also bought some HP-IL equipment. I made a few programmes on it, but it was almost always occupied by my brother using it.

Around 1985:

I sold my Sinclair ZX-81 to my teacher at the electronics class Joern Hanghoej, at Thyboroen Skole. He must have had some considerations about buying the computer from me, appearantly meaning that I sold it too cheap to him, because he asked me several times, if I was sure about the price. In danish he said; "Det er sgi' billigt Johnny. Det er... Det er... Det er..."

Some weeks later I visit him and his family, and saw that he had made a external keyboard for it, and a lot of programmes.

To replace the ZX-81, I bought a Commodore VIC-20 at Lemvig Foto, and continued programming Basic, with a lot of new features in Commodore Basic. Having sold the Sanyo black and white television, the Television war started again. It was great to have colors on the programmes of the VIC-20. By this time, my little brother Allan also started to pay interest in computers, and we spent a lot of time entering programmes from magazines as the danish "Ny Elektronik", UK "Your Computer" and others. It was very exiting to spend a couple of hours entering, as Allan read up from the program listings, finaly typing "run" and, as in most of the times, watching the VIC-20 crash or just perform a cold reset. Swell!

Later I got some modules for the expansion port; games like Poker, action game "Mole Attack"

After a while, I got to know the VIC-20 real well, and I was able to write programmes that could plot graphics, pay music and make sounds like explotions.

Around 1986

Rudi sells his HP-41, and buys a HP-75C. The HP-IL is usable with this too, and he buys a HP-IL Video Interface too, wich I was very impressed by.  

Around 1988

Rudi gives me his HP-75C. I make a few Basic programmes for it, and uses it for a couple times as alarm clock, during my time in the army.

Around 1990

Im starting on my elektronics study class in Struer Tekniske Skole (Technical College in Struer Denmark). I have just a couple of months before recieved my brother's HP-42S, as he had bought a HP-48SX himselves. Also I bought a Epson HX-20 at this time. It was a great computer. Also at this time, I made the first of my great errors, as a future HP-collector: I sold my HP-75C (doh!).

About 1991

Working along the school, I bought a HP-48SX. This is surely the calculator that I have worked most on. I write many programmes, and saves it on diskettes, uploads, downloads files constantly...

About 1997

Im selling the HP-48SX (the second of my great errors, as a future HP-collector) to afford a new piece of technology; the US Robotics Palm Pilot Personal.

December 2000

I start collecting HP-calculators. My brother Rudi has wrapped his HP-48SX as my christmas present. This gets me started collecting. Today I have about 28 different HP-calculators in my collection, still getting new calculators once in a while.

Edited: 27 Apr 2004, 2:59 a.m.


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