I liked this story about the Rockwell 63R calculator – it’s about 2/3rds of the way down on this web page. I still have the one I bought with the help of a Rockwell employee who got me a very good discount. I also have another one that I picked up later. I used mine for a few years during my college classes, then bought the TI SR-56 which I still have, but it now has one bad LED digit (see photo). I really liked it. I remember that it didn’t have the quirk (I don’t think it was an error) that the 63R had, but I can’t remember what that was.
My SR-56 was a great calculator; it could be programmed with simple key stroke sequences and pauses to input the data. But the display used power hungry red LEDs, and I had to sit next to a wall outlet in class in case the batteries ran down in the middle of a test or whatever. When the fourth digit went dead (see photo), I started multiplying the result by ten to shift everything to the left one digit, so I could read that value. I have opened up the TI SR-56 to see if there was a way to repair the bad digit, but it seems that the problem is inside of the display. That’s not possible to fix, so I can just use it for a cool looking display, since it’s really a lame calculator.
By that time, the prices of calculators were dropping and they came out with the LCD liquid crystal display. The batteries would literally last forever. I went to Sav-On to buy a Sharp scientific calculator and I noticed that it said 3V, 0.0002 W on the back. That’s 2/10 of a milliwatt, or 200 microwatts! A very tiny amount of power for the calculator’s two AA cells. I went up to the cashier to pay for it, and she said that she would sell me two alkaline batteries to replace those cheap batteries included in the package. I said NO firmly. knowing that there was absolutely no reason for them to be better than the ones already in the package. They had the Sharp name on them, and I used the calculator with those Sharp batteries for many years with no problems.
I bought the HP 20S calculator, which is not RPN, just a regular algebraic calculator. Then I liked it so much I bought another one, even though they were twice the price of other comparable calculators, I have had other calculators but they seemed to go bad a few years after I bought them. Usually the problem was the keys would give double or triple digits when pressed. Sometimes the LCD display would fail on one or more segments or digits. The typical calculators were made with a case that snaps together, no screws. Obviously they didn’t design them to be repairable. I’ve taken a few apart, and found little or nothing inside other than the keyboard, the display, the batteries and a black blob on the circuit board, which is called COB, or chip on board. Everything is made so cheaply that there is no way to repair it.
Later I got another TI calculator, the TI 30 Solar. I still use it, actually them, because I bought several. They have a solar cell and don’t need batteries. I’ve noticed that almost all of the scientific calculators have binary to hexadecimal conversion that gives errors or the wrong answer. The TI and most of the other brands have this issue. There are a very few that do not, including the HP 20S. I set the HP 20S to BIN and enter 1011001100, then convert it to HEX, and it says 2CC, which is correct. Then I convert it back to BIN and it again correctly says 1011001100. But I try that on another calculator such as the Sharp EL-501V. I set it to BIN and enter 1011001100, then convert it to HEX, and it incorrectly displays FFFFFFFECC. Then I enter 2CC in hexadecimal and convert it to BIN and it gives E for error. Most calculators have this issue, and it’s fortunate that very few people use binary to hexadecimal conversion, This is why I like the TI 30xa Solar, because it simply doesn’t have binary or hex.
I’m back with a new calculator,. the HP 50G graphing calculator. It’s programmable and even has an SD card slot. I have a lot to learn before I’ ll be proficient with it.