MILSPEC TEARDOWN: CP-142 RANGE COMPUTER

As some of my preceding paintings at Hackaday will attest to, I’m a large fan of the World War II generation. Something approximately going in with wooden airplanes and leaving with jet combatants and area-capable rockets have usually captivated me. So whilst one in all my lovingly crafted eBay alerts changed into precipitated by using something claiming to be a “Navy WWII Range Computer”, it’s safe to mention I changed into interested.

Not to say I had any concept of what the component became, mind you. I only knew it looked vintage, and I had to have it. While I eagerly awaited the tool to reach my doorstep, I attempted to perform a little research on it and got here up pretty a great deal empty-surpassed. As you may think, a whole lot of the technical facts for hardware that changed into developed in the 1940’s hasn’t pretty made it to the Internet. Somebody become selling a technical guide that potentially might have blanketed the feature of this device for $one hundred on another site, but I concept that is probably a chunk immoderate. Besides, where’s a laugh in that?

I decided to attempt to decipher what this device does through a careful exam of the hardware, consultation of what little technical records I could pull up on its personal components, and some modern gear. In the cease I suppose I actually have an awesome idea of how it works, but I’d actually like to pay attention if there’s all of us available who might have in reality labored with hardware like this and could fill in any blanks.

 

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OVERVIEW

The first thing I changed into struck with turned into how large and heavy this aspect is. Compared to modern hardware, the CP-142 is constructed like a literal tank. It’s built of thick folded sheet metal with a captivating crinkle coating of a few kinds that simply screams “Old School Military”. It’s roughly the scale and form of a toolbox, with a gap on the bottom that makes me assume it was at the start meant to straddle some different piece of hardware. Controls are very minimum: there’s an energy switch and “Intensity” dial on the left, and a window to view a mechanical readout on the right which reads “Miles”.

On the side of the tool, there’s a 70mm graduated dial which actions the counter when it’s turned around. It’s straightaway clean that rotating the dial is supposed to set a selected distance, but more on that later. After loosening two thumbscrews on the lowest, the CP-142 may be opened up on a hinge to view the internal components. Two truly categorized first-rate adjustment knobs close to the number one manipulate seem to indicate that starting up the hardware to fiddle with the internals was not unusual. There’s even a little hex key stressed to the body of the tool which can be used to loosen or dispose of the control dial, possibly so the operator may want to align the marked graduations with the pointer on the front of the case.

ELECTRONICS SECTION

The left-hand aspect of the CP-142 is dedicated to electronics, which consists of 4 12UA7 tubes, a 6AK5, a 6AL5, and a Raytheon UX-7350 transformer. There’s no PCB in this tool, all the wiring is executed factor to a point, with a few tough metallic “rails”.

WIRING

A thick package deal of wires comes out of the electronics phase into a bus bar that’s placed right below the lid hinge. There’s also a transfer here that cuts electricity to the device when the lid is opened. Clearly, the device would be opened sufficient that a safety interlock and methods to save you twine fatigue from repeated commencing and remaining become deemed necessary.

The bundle of wire is wrapped up with loops of black thread every 10mm or so, which was achieved via hand. It’s first-rate to feel the connection to the producing staff of the time. In all likelihood, a woman who was a part of the exertions force who stepped as much as help the battle effort turned into tasked with tying those little thread loops round bundles of wires for 8 hours a day along the one’s employees routing the wires and doing the point-to-factor soldering.

Above the bus bar, the wiring goes to the power switch, depth dial, and a bulb which lights the mechanical show. The construction of the transfer is something I’ve by no means visible earlier than, as in place of having a Bakelite body as you’d normally anticipate from the technology (and that’s present in different areas of the CP-142), it’s fabricated from sandwiched pieces of some fiberboard.

Explorer. Beer trailblazer. Zombie expert. Internet lover. Unapologetic introvert. Alcohol fanatic. Tv ninja.Once had a dream of buying and selling sauerkraut in Ohio. Practiced in the art of building crickets in Nigeria. Gifted in donating wooden tops in Fort Walton Beach, FL. Spent 2001-2007 testing the market for corncob pipes for no pay. A real dynamo when it comes to managing catfish in Jacksonville, FL. Spent a year investing in yard waste for farmers.

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