The Museum of HP Calculators

HP Memories Forum

[ Return to the Index ]
[ Previous | Next ]

LEDs, TIs, and HPs.

Posted by Jeremy on 23 Mar 2003, 9:46 p.m.

I have always preferred LED displays to LCDs. They are easier to read and just have a certain charm to them that is very hard to explain. That they actually 'emit' light rather than just displaying something is just awesome to me.

It all started a couple of months ago. I spotted an old TI-1200 calculator on a shelf in my grandpa's bedroom: Jeremy: "Pop, do you still use that?" Pop: "Nope." Jeremy: "Can I have it?" Pop: "Sure. Knock yourself out. I remember paying $150 for a TI in the 70s... it was the first one with square root" (He was referring to the TI SR-10) {I don't know if that is true or not, I think the HP 35 may have predated the SR-10 but maybe it was so expensive he didn't consider it}

So I took it, put a fresh battery in it and kept it next to my computer keyboard. I used it for things like balancing the checkbook and such. Every time I turned the thing on and saw that sharp little red LED display, I smiled. I had to have more.

Off I went to eBay, where I bought the Sanyo 'Mini Calculator' which is AC-only powered and the size and shape of an old transistor radio. I've seen the inside of one of these, and the display I think is what you guys call "Pixie Tubes"? They look like little neon bulbs. This one seems to work more like an adding machine than an typical alegebraic calculator. (for example if you want to subtract 3 from 6, you would key: 3 += 6 -) Multiplication and division work normally, but if you want to subtract, you have to hit the subtract button AFTER you add it. This one has a beautiful amber display. $8 + $8 shipping.

Next, I found the coolest little Casio Personal Mini with a green LED display and the sideways format. I bid on that and won it for $12. The guy shipped me the wrong calculator, a Unisonic 888. I decided I would be open-minded and try it. Two of the keys didn't work and there was corrosion all over the terminals. So I emailed the guy and let him know. He said "Keep it and I'll refund the money. It's not worth all the shipping charges. If I find the Casio, I'll send it to you." Nice. So I took the thing apart, cleaned off the terminals and fixed the keypad. It was not the HP type of keypad. It was the mushy kind where each key had a spring, a contact, and a couple other pieces. It was an absolute nightmare getting it back together properly. It turns out that someone before me had it apart and couldn't get it back together right, and so two of the keys didn't work. So that one was free, and had a nice green tube display. (which looks like LEDs) $0)

Next, I got to thinking that although I like these LED calculators, they won't do me much good in the Advanced Communications class I'm taking. So I went back to the Datamath site and did some research. What I wanted was a classic TI scientific with enough scientific functions to be useful to me in school. I also wanted it to be not too collectible as I wanted to buy it and use it. So I got a nice first generation TI-30. (Red LED display again) I think I paid $22 for that one. It came with a vinyl case which was made to look like denim. (Did people actually wear these on their BELTS??!!) My fellow DeVry students were having a good laugh at me. My one good buddy in particular is in this phase where he's dressing as if it's 1971 outside. So I let him know that he could laugh at my calculator, but it's newer than his pants!

Then, I remembered the nice keypad my 48GX had before I sold it out of discouragement that it was so unintuitive to use. So I figured older HPs might be simpler and have the coveted LED display. I surfed over to eBay and was floored by how much they were going for. $300 for a 30 year old calculator? They must be good, or collectible, or both. I didn't buy that HP 35, way out of my budget right now. Still, I wanted an HP scientific with an LED display. The first thing I saw that fit the description that I could afford was a heavily used hp 45, which I won in the auction for.... $45. No battery, a dirty and sticky keypad with 'keys that had to be pressed hard to work', dirty keypad outside, cracked battery door. No problem, I could fix or deal with all of those things. I took 'er apart, cleaned out the keypad, built and hardwired a AAA battery holder and away I went. It wasn't quite that easy, it took an entire evening to do it. The first time, they shift key didn't work. So I took it apart, hardwired the battery holders and gently cleaned underneath the shift key with a toothbrush and some 91% alcohol. When I got it back together, the shift key worked, but the 1/X key didn't. So I took it apart again and cleaned THAT one. It worked, but now some other key didn't. So I took it apart again (thankfully this is very easy to do) and cleaned all of the keys. I replaced the plastic sheet that separated the keys from the rest of the environment. (using a wrapper from a package of Radio Shack AAA battery holders I happened to have on hand; it looked like about the same kind of plastic) Anyway, now it is very clean inside and out, and works like new. It still looks very worn; you know how they get shiny from years of use. It feels a little odd though; using something that has that worn, shiny feeling that I have only had for a few weeks.

For some reason, (cough cough, have I caught something?) that wasn't enough. I had to have more of that elusive HP quality. I discovered MoHPC and read for hours for about four nights. As nice as that hp 45 is, it doesn't do complex numbers and matrices. True, my trusty TI-85 does all that, but it is not quite the same. At this point, I was starting to really get used to RPN and develop a distaste for algebraic. (although it is very well implemented in the TI-85) I decided I should get a 15c. What?!! They're discontinued and selling for over $200 on eBay?!! Bogus. Next, I decided that a 32SII would be good. Seemingly, Amazon still had some, they they were selling for $240. :( How COULD they? A quick trip over to eBay explained it. They have been discontinued and are fetching crazy money. About $220 at that time. Then, I got to thinking, if those are selling for so much on eBay because they're collectible, does that mean that some of the newer high-powered ones are out of favor? Yes, it did. I picked up a 48G with manuals and a couple minor dents to the faceplate on eBay for $40. Even if I didn't use all the fancier functions, it was worth $40, right? That huge easy-to-read display shows four levels of the stack and probably is better on batteries than the LED display of my hp 45.

Last night is the final chapter. (hopefully) I was surfing around on eBay and out of curiosity, I wanted to see what the 32SIIs were going for. $250 apparently! Blimey. I changed the priority and had it display the newly listed items first, and someone was selling a nice condition 32SII with case for $125 with 'Buy it Now' So I jumped on that without a second thought. The interesting thing is that I can't really afford it right now, but I know that if I feel any remorse, I can get back my money and then some. For a while now, I'm going to have to stay the hell off of eBay or I will find myself in trouble. ;) I'm just going to read this forum and be a good boy. Maybe actually learn how to program the 48G and 32SII.

Side comment on my TI-85. I bought this in about 1991 in high school. It has gotten me through all of high school, and the first three years of Electronics Engineering Technology. It has had my name carved into it, the battery door, and the slide case with my Swiss Army knife. It has been dropped once or twice, but not too badly. It is shiny and worn, and has earned its retirement.


[ Return to the Message Index ]

Go back to the main exhibit hall