Scientific Calculator

Speaking of HP calculators, this month's Circuit Cellar has a project in which somebody re-implemented the guts of an HP41 with FPGAs.

I have both, also. The 15C was going to get scrapped at work, the 16C I forked out Big Bucks for back in '82 when it first came out. I was working with a 36-bit mainframe, so the TI "programmers" calculator didn't cut it. Needed up to 72 bits for double register ops and converting EBCDIC to EBCD characters. Not a whole lot of messing with paper dumps and machine language going on now, so there's probably not a lot of call for a 16C on the market. Except for programability, I've also got a $6 Sharp that does just about everything that the 15C does except it doesn't use RPN. The rechargeable batteries seem to be the weak spot on those old calculators, those HP "business-card" sized ones use button cells so will probably keep chugging along as long as the battery compartment doesn't get leakers.

Stan

When I was in highschool, my Physics teacher spent a good portion of his yearly budget on a Heathkit calculator because it did square roots and basic trig functions. About the time we finished soldering it together, HP came out their programmable pocket model (with the magnetic cards) and the prices fell on all the other calculators. I he had waited a year he could have bought a fully assembled calculator with a lot more functions for less than the Heathkit.

Paul K. Dickman

I had a SR-51II that was stolen while I was stationed at MCAS Beaufort, it was replaced with a SR-56 that was a lot of fun to play with back then. Hey at least I had something I could program. Sucked having the program go away when you turned it off.

Ah the days of red leds.

Now I use easycalc on my Palm T|E. It isn't programable but you can create your own functions.

I just wonder how much longer I can stay on a palm platform. I guess my replacements will be from ebay.

Wes

I graduated College Physics / Mathematics with a K&E log log duplex Decitrig and a Vector log log by Dietzgen.

That was in 1969.

Our finals were all day tests in Physics. Typically 4 questions. We brought lunch and drinks unless we drank coffee. And lots of pencils and a sharpener and drafting eraser.

Mart> When I was in highschool, my Physics teacher spent a good portion of his

I still remember lubricating the K&E with Talcum Powder. Of course, I used too much!!!

Martin Eastburn wrote: .

At least from when I started looking at them, "saving money" didn't seem to be a feature of a Heathkit product. Given the amount of work involved, the savings would be negligible. Seems like they were at least 70% of a retail product, if not more than one.

Bill

They weren't in the 40's, at least for things like a VTVM. ...lew...

This was in the early '70s. If I remember correctly, the Heathkit cost around $150 and the similar HP cost over $300. That was a boatload of dough back then.

Paul K. Dickman

That happened in the 1960s or 1970s (I was building Heathkits around

1970 or so, when you might still come out ahead if you valued your time at $0.00/hr) when automatic assembly really took over in electronics manufacture. In the 1950s and before, *somebody* had to do all that assembly work. With a Heathkit, you didn't pay somebody at the factory to do it.

Thank you for the history lesson. It puts everything into perspective. Bill

Or the '70s. I paid less than 25% the cost of a commercial VTVM and built it in about an hour. Maybe it takes Bill several days to assemble a simple kit?

BTW, I saw a decent looking heathkit VTVM for $2 at a fleamarket Saturday afternoon, but the owner wasn't around. When I came back a little later he had covered everything and left.

I saw my first catalog in the mid-80s. I think they stopped making the kits in 1991. I never had a chance to do one of their kits, though that didn't keep me from making things. It's true that I'm not real quick..I'm more the careful type. I'd probably spend the first day reading the directions.

Bill

I am careful as well, but I never took more than 25% of the suggested construction time. There isn't much in a Heathkit assemly maual other than pictures of where each part goes, and checklists of each part used on that page. It took longer to inventory the parts than to build a kit. I built several of the VTVMs. The last one took a little over 15 minutes from the time I cut the packing tape. That was for one of my uncles. I also finished building kits for people who gave up. I always gave a high quote becasue I hated cleaning up someone's mess. :(

I built a fair number of Heathkits in my day. The most complex was the AM/FM/Stereo receiver and preamp. I forget how long it took me, but it was significant. It worked from the start. I still have the VTVM.

As for the time estimates, Heathkit used to boast that they tested their kits and instructions by giving one to a housewife. If she could put it together, it was hers to keep. Most succeeded.

Joe Gwinn

Hmm, I had a Heathkit VTVM (I may still have it, but I'd have to dig through the garage to find it). I remember it as being fairly easy to assemble, but nowhere near just one hour... don't remember the price comparison.

My dad and I peaked on a black and white TV (note -- he was color-blind, so I had an important role!). Unfortunately it never worked right... they gave us our money back, and I noticed the next year's catalog didn't have that particular TV in it any more (though it still had the color TVs).

I remember the legend (everybody knows this is true, but I don't remember ever seeing an actual statement from Heathkit about it) that they tested their instructions by giving a kit to a secretary or somebody on the loading dock. Whenever the tester had a question, an instruction got clarified. Repeat until no questions.

What I found both sad and amusing was the most screwed up Heathkits were built by Hams & CBers. Wrong parts, bad or missing solder, and 'customized by morons'. :(

The kit was something like $18, and a RCA 'Senior Voltohmist' was about $100. If you went to HP or GR, it was several hundred dollars.

As far as working quickly, I was able to work a lot faster than any tech in the shop. Until the Carpal Tunnel set in. Now I have trouble not dropping small tools.