Posts Tagged ‘legacy technology’

Legacy Pan-Tilt for Video Camera

22 April 2017

pan-tilt for video camera

pan-tilt side cover removed

This piece of “legacy” tech isn’t much to look at. It was the first item I photographed but the last I am making a post about.

I got it from my brother when his company upgraded all their video equipment to more modern stuff.

This was possibly made to sit on a pole and hold one of those large surveillance cameras that you still see some places. But this unit was being used inside to hold a camera much smaller than it is (though heavier than modern cameras that are fully electronic).

pan-tilt with main cover removed

It originally had a long control cable so it could be moved around from a remote location. The controller (shown underneath) simply switched the motor drive voltage (about 24 volts AC) between four different drive windings on two different motors – forward and reverse for each motor. There are little switches installed in the housing to turn the motor off if it tries to move beyond the mechanical limits of the housing. And that’s all there is to it.

With the advent of much smaller cameras, pan-tilt units no longer need to be this large and heavy.

Voltage Divider Assembly

10 April 2017

voltage divider assembly inside
A few years ago I purchased a pair of differential voltmeters because I was looking for aluminum equipment cabinets and thought these might work. The front panels were actually a full 1/4-inch think, which was a little more than I bargained for. These were military-grade equipment, and I think both of these items had been in use by the Army.

I got them from Fair Radio Sales “as-is.” The shipping cost almost as much as the equipment did. These meters were made by John Fluke Mfg Co, Inc, of Seattle in the early 1960s. They used mostly vacuum tubes and various other technologies now considered Legacy. The idea behind a differential voltmeter is that you compare a known voltage with an unknown one, and use a meter to tell when they are equal. The settings you used to get the known voltage are then equal to the voltage you wanted to measure. Ponderous. Today’s digital voltmeters do the same thing, except they “turn the dials” for you and present the result on a readout screen.

voltage selection dials

Marked dials function as an old-school digital readout.

This assembly is just the voltage divider for the known voltage. It consists of a set of switches and precision resistors arranged so that when you put in a reference voltage, the output equals the voltage you dial in. For accuracy, the resistors used have to be high-precision. These ones have a tolerance of +/- .02% which these days is unheard of. I saw a refurbished working version of this equipment for sale for over $1,000. It’s considered an ultra-precise laboratory-grade device.

inside the voltage divider

From what I can tell this equipment was entirely hand-assembled. That was how it was done in the “old days” of electronics. The colors involved are kind of pretty but they also served to help the assembler be sure he or she had the right part or was sticking the right wire in the right place. All the resistors were made of lengths of fine wire wound onto forms then glued in place with clear paint. Fluke may have constructed the rectangular ones themselves. The yellow cylindrical ones were made by an outside firm.

voltage divider back side

I couldn’t get over the workmanship put into these components, so I kept one of them. But this one is now extra and is destined for the recycling center.

High Voltage Divider

8 April 2017

100KV high voltage divider

Here’s another piece of “legacy” technology. However, in this case the manufacturer, Spellman High Voltage Electronics Corp in New York, still offers this device as the HVD100. This is the smallest model, for up to 100K volts. That’s 100,000 volts. The input voltage can be monitored at a ratio of 1,000 to one, or 100V full scale, or at 10,000 to one, for 10V full scale. The total resistance of the column is 1,000 Meg ohms or 1 Gig ohm.

I bought this unit on eBay as basically a piece of junk. I was curious what it was, as the description wasn’t clear. It arrived slightly damaged. I disassembled it and altered it a bit to strengthen it and make it easier to take the top and bottom electrodes off. All the rounded parts are for the purpose of reducing arcing. Arcing will interfere with measurements, creating momentary lower-resistance paths across the device. However, the top and bottom electrodes make it really clumsy and difficult to transport. It is designed for laboratory use, and includes a sparse but descriptive label and BNC connectors to attach measuring equipment.

high voltage divider detail

As with many of the items I have kept around, this one has a certain aesthetic value, but I never use it. Though I find high voltages exciting, they are difficult to produce and dangerous to handle, and really beyond by current experimental capabilities.

Depth Sounder

3 April 2017

Here’s another piece of equipment destined for the dustbin (or in this case, electronics disposal center). I found this a few years ago at the Goodwill Outlet in Seattle. As far as I know, it is totally functional.
It does, however, lack the transducer needed to make it work on a boat.

legacy depth sounder

Location by Echo

Radar, Sonar and related distance-finding technologies all operate on the basis of echo-location. It’s a clever system, because you can measure both distance and direction from just one point. With visual methods you need two or more points to view from so you can triangulate.

In the case of this device, the transducer is fixed to the bottom of the boat, so it only points down. Thus, “depth and fish.”

Whereas cheaper versions are geared only to tell you how much water you have under your keel, this one is rigged to display multiple echos from different depths. Judging from the difficulty I had in finding the user’s manual for this instrument, I would guess it was built and sold before internet shopping became popular. Modern versions still operate on the same principle, but are computer-based.

Here’s the electronics:

depth sounder electronics

Relatively simple. It operates on the boat’s battery, 12 volts. There’s a connection for the transducer (I moved it from the back). There’s a motor to spin the lighted indicator, and some logic circuits. If you’re into electronics, you’ll also notice some RF (radio frequency) parts on the board. Per the manual, the transducer operates at 200KHz. That’s RF, and as sound, classifies as ultrasound. It’s ten times higher frequency than what we can hear with our ears. I don’t know about fish.

Toroid Transformer

26 March 2017

This is the first of a short series devoted to items of technology I have run across in my pursuit of my electronics hobby that were once “cool” but are now seldom used. Most of the things I will show here are destined to be thrown away or otherwise disposed of, as I have found no use for them, either.

The Toroid

The toroid is a big deal in some branches of New Age Physics and is a significant concept in regular physics as well.

Technically, “toroid” describes the shape of a torus or similar geometric object. It is, however, used as a noun. The shape is, colloquially, a “doughnut.”

Coils wound on toroid cores have been around for a long time, as they have certain advantages to cylindrical coils or square transformer forms. The magnetic field they generate tends to stay inside the core, so they emit less electromagnetic interference.

Toroidal parts are a little tricky to manufacture, but the need for them has become so great that they are now commonplace. However, 60Hz (or 50Hz) power transformers are a rarity in electronic equipment nowadays, having been replaced by high-frequency transformers. They are still used in electric power systems.

My Transformer


This transformer came in a video distribution rack made by a company called Sigma, probably around 1995. The primary takes line voltage (120VAC) and the secondary outputs about 30VAC with a center tap. It was used to make a +/- 15V power supply. That power was fed to amplifier modules that created +/- 12V rails using on-card linear regulators. The amplifiers were high-power op amps connected in current mode. They only needed a voltage gain of 2. Each card had two. This was for old composite video. Composite video is out of style now, so all the equipment that was made for it (and there was a LOT!) is now just this side of junk.

The future of legacy technology

Does old technology have a future? SciFi writers have speculated about this. What if this planet gets downgraded and we can’t make modern technology any more? Would older “junk” technology help us recover? And what if we travel to a distant planet that turns out to be less advanced than ours? Would it help to have an older technology available that would be usable there? These are actually ancient questions, but not even LRH ever really goes there. It gets mentioned in accounts of ET history every now and then. If the true data about Antarctica ever gets released, it would be quite a revelation, and this question comes into play in those ancient events.

But I must say, this thing weighs about 5 pounds and is now replaced by technologies weighing less than 1 pound. You could never take it into space using our rockets. But should I keep it as a novel paperweight?

toroidal power transformer upright

It is somewhat interesting to look at.