Eldorado Electrodata Director Two Calculator Page


Director Two Calculator Small
Things I Know About This Calculator
A Little Information About Eldorado Electrodata
Company Info
Curious Things
Taking It Apart
Things I'd Like To Know...



Dave Fase sent me some wonderful information regarding Eldorado Electrodata. You can read it below, under Company Info. Many thanks for the info, Dave!


I'm not much of a calculator collector by any definition, but when I saw this calculator at a Habitat For Humanity thrift store, something about it was just too cool for me to leave it there. The $2 price tag and the fact that I was helping out a good cause didn't hurt either.

When I got home with it, I did some Googling around and found that there doesn't seem to be much information available concerning these calculators. That's why I wrote this page up--to share what I know and maybe find some answers to questions I have about this calculator. Please let me know if you have comments, information or even questions. I'd love to hear from you!

I am actively using this calculator as it is a very nice unit, and I have often found that disuse often causes far more failures than regular use when it comes to old machines.


Things I Know About This Calculator

A Little Bit About Eldorado Electrodata

(Courtesy Nigel Touts of the Vintage Calculators Musuem... Thanks!)

I don't have much information about Eldorada Electrodata. "The Collectors Guide to Pocket Calculators" says: "Eldorado Electrodata Corp. of Concord, California, was originally an electronic instrumentation company that
branched out very briefly into electronic calculators. They produced a few AC-only, desk-top models and even fewer "portable" versions." As well as the 8KB desk-top model, also mentioned are the "portable" models Mathmagic and Touchmagic B.

You can see the calculators mentioned above (including a Director Two!) at the Vintage Calculators Musuem...) And if you should happen to have any more information on Eldorado Electrodata, I'd love to hear about it!

Company Information (courtesy Dave Fase, in reponse to a post in rec.antiques.radio+phono)

Eldorado, a privately held company, went bankrupt in about mid `74.

The calculator business was a good part of the reason for the company's demise. The business also had a small line of some of the best counter-timers and "nanosecond timers" available anywhere. Much of this was sold to the government. Mini computers, (big as a washing machine), and memory systems were also developed and marketed.

The calculator business started with the model 8C which was about the size of a two high computer keyboard. Original MSRP for this 4 funtion 8 digit calc was $349.00 in the early `70's. Early 8K machines utilized an "un-buffered" TI chipset. Needless to say, some shuffling across the office or home carpet would kill the chipset. Buffered chipsets weren't employed until many thousands of the model were shipped with house and other brand names (such as Addmaster, Sears and Roebuck, Marchand, Tax Corp of America, and many others...) emblazoning that little piece of foil below the readout window.

S.S. Kresge bought a majority of the 8K's, on which we affixed their K-Mart name. K-Mart units sold like hotcakes near the end due to their $40.00 sales pricing. This price was about one half of our construction and boxing price, and about a third of our MSRP of $129.95. Needless to say, with a one year warranty, thousands of un-buffered sets were returned, lawsuits and counter-suits were initiated, and the end of a good company was on the horizon.

I was recruited from Systron-Donner across town in early `73 as Eldorado's "National Service Manager". I thought I'd been in a pressure cooker at SD, but the move was like tossing a live lobster (me) into a pot of boiling water. My department was faced with the repair and return (most often warranty) of up to 350 calculators a day. Techs numbered 18 plus a few more part-timers, plus several contract service stations world-wide. The company comptroller hated to see me come through his door, because most repairs were simply replacing the chip set or the entire mother board. My department was simply a finger in the dike, so to speak.

Near the end, a model 12K (had a few scientific type features) calculator, plus a few handhelds were developed. None of these sold very well.

Also manufactured was a neat little seventies style clock, one of which keeps time in my living room.

After I bailed out, SD re-hired me to be part of their new "Service Division", located in the then ex Eldorado facility. Man, if those walls coulda talked!

Curious Things

This calculator has a constant (K) key, but it only seems to work for multiplication and division. It has no effect on addition or subtraction operations. Also, when a calculation is performed, the display is not blanked out as with most modern calculators. This leads to some interesting display patterns when the unit is told to calculate an answer. Unfortunately, my digital camera is way too slow to capture this strange and interesting behavior.

I'm not too surprised by this, but this calculator doesn't like having the power cycled too quickly. What's interesting about this is that even 10 seconds may be too quick. At times there is also a short delay before the unit powers up. Should you cycle the power too quickly, the display will fill with errant characters. However, the characters do not change each time. There is either a long string of numbers that remain the same or a simple 0.6 notation at the extreme right of the display. In either case, pressing the clear key will bring things back to order.

Next to the power switch is a switch blank. I've seen one example of a clone of this calculator with a switch in this location as well as an "uplevel" model with the switch. The switch seems to be used for selecting from 4, floating, or 2 decimal places. Mine does not have this switch, but I would assume that the circuitry probably has all the required provisions if I were to add it.

This unit is not UL listed as far as I can tell. The only seeming safety mark on it is an "Approved For Electrical Safety - City Of Los Angeles - Department Of Buildings & Safety". I find that odd...

Taking It Apart

WARNING: Taking your calculator apart could cause severe damage to it if you are not careful while doing so. Remember that in addition to containing static sensitive parts, you will be working with assemblies that likely have not seen the light of day in 30+ years! As a result, things like soldered connections may have weakened over time. I am not responsible for the results if you take your calculator apart and damage it.

Taking this calculator apart is pretty straightforward. Four philips head screws are in the bottom of the unit. Take them all out and then the top cover will lift off of the unit. While the buttons will stay in the bottom of the unit, the power switch (and probably the decimal precision switch) is attached to the top cover. It is my personal experience that you MUST be careful with the wires leading to the switch. Otherwise one or both may be ripped off with careless handling. I had to solder one of the wires back on after it broke with only a gentle flex to set the cover aside.

Things I Would Like To Know

I am curious to know how many colors the Director Two was offered in. Searching around the web showed at least one yellow unit, a black one and a green one branded as a "Zumro 100". I'd also like to know about how many of the Director Two model were made.

Looking up Chalomar Road in Concord, California via Google Earth seems to indicate that the 600 block no longer exists. Eldorado Electrodata gave their address via the informational label on the bottom of the calculator as "601 Chalomar Road, Concord, CA 94518.


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Copyright 2004-2014 by William R. Walsh. All Rights Reserved. Permission to reproduce this page in its entirety, including this notice, is fully granted so long as no more than a reasonable fee for duplication or media cost is charged. Last updated 03/16/2014.