No you don’t

Previously—-

No, wait. Not you again.

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Not on my watch.

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Say “Magic Smoke release” again. I dare you. Feeling lucky, punk?!

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Dip packaged op amps on this one. Curious.

I caught this one JUST STARTING to smell like hot plastic and having blown the fuse for one side of the bipolar supply…. Luckily the equipment it took audio from seems to be long gone, as is whatever it supplied.

A tale of amplifiers.

Here’s a story I’ve been meaning to tell for a while.

Once upon a time, there was a wonderful isle of dreams, and a television station built upon it. To carry the sounds to accompany its magically delivered pictures, there was a set of audio distribution amplifiers.

And oh baby what amplifiers they are….

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The guys on the right. Ignore the dark power lights, they're soldered in incandescent...

And their, uh, not the best side

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The company stuck around until 1985

And now the heart:

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Those of you who are like me will also notice, this is six individually transformer isolated outputs and one transformer isolated input.

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Fairly simple amp stages.

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The dual power supply. One regulator on each end. This is the older design; the newer one has two separate regulator cards.

These lived happily until one day, one regulator card let out a biiiiiig fart.

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For comparison, this is what the other end looked like:

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Oh how it stank that morning on the wonderful isle of dreams!

The finest nose on the isle located the stench and an engineer set to restoring the precious music of the angels to flow beyond it. Fortunately he found only two channels still in use, each feeding one output… Thus:

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Emergency passive near unity gain audio distribution system.

This engineer was haunted from that day by the knowledge that some very mission critical audio still runs through that stack and the amps aren’t getting any younger.

However, they are, at least, better than the modern equivalent.

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I'll just take my chances with the old Ramko Research shit boxes, thanks

ESP Surge Protectors

I’ve used these for years whenever I find them on the surplus market. These are really good surge protectors. They often have a label saying not to remove them — they are usually deployed on installation of fancy leased office copy/scan/print/fax machines costing kilobucks and are required as part of the service agreement.

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The green LED on this one is just a power on light. Note that some units have a safety relay inside and will not power on unless a good ground is present. They’re idiot proof. You’ll see momentarily why the ground is very important.

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All of them can be opened without damage. On this one you pry from the back and carefully release locking tabs.

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That… Uhh… That’s a static sensitive warning. I’m guessing that was some engineer’s joke as there are no static sensitive parts in this unit at all.

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Here’s the good part. Surge protection on the inlet – line and neutral first meet these MOVs and gas tubes. Now this unit is kinda interesting in that it’s wired like this:

Line in —-{two MOVs in parallel}—[gas tube]—ground—[gas tube]—neutral

Normally I see the gas tubes and MOVs in parallel.

Not gonna question it; it works.

Now those are just the castle gates. There are more defenses beyond…

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L network filters in line and neutral. Each must flow through an inductor on its way to the equipment. Once it passes the inductor which will resist the passage of both high frequency gibberish and spikes with fast rise times, a capacitor damps out the high frequency components. If you’re curious as to how this works, go deeper down the rabbit hole and research basic filter design. It starts to get quite fascinating.

One cap goes from line to neutral, two go between L/G and N/G. One resistor up before the inductors will bleed residual charge off these upon unplugging for safety.

This is a feature not present in most AC powered smoke alarms. Don’t touch their pins after disconnecting them. They bite.

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Additional MOVs are provided here and are behind 2 amp pico fuses. Not sure why the fuses are used, but for a surge to hit these, it would have had to get through the primary defenses.

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Telco protection stage; this uses poly switch fuses for current limiting (self resetting) and MOVs to limit voltage.

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The MOVs can even be replaced if they pop.
Cool, right? I’ve never had any gear get damaged plugged into one of these. They Just Work.

How to best enjoy “The Real”

Just sit back, relax, and light off a bad CPU fan.

This CPU fan is off a $LOLWTF robotic broadcast camera control system. “Enter Bearing”? Sleeve bearing. They cheaped out on the fan!! Why?! When you pay THAT MUCH for a product, is it wrong to expect it to be built to last?

Well then. This is more enjoyable than a badly done demonstration of how to give yourself waves by braiding your hair and baking it to death with a flat iron.

I may just be the new guy buuuut…

Why? Why does a burned out Evertz VIP multi-viewer card smell like sightly burnt pancake syrup?! The card won’t show any signs of life upon receiving +12vdc power from the Evertz Multiframe. It’s gonna go back for some tender loving care at the factory.

We’ve had a rash of failures on these boards as of late and that makes life interesting when there are a LOT of them in service throughout the facility.

The soundtrack for pondering this nonsense is below.

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One horribly expensive short stack.
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Audio input section. The card can take audio from all the incoming sources.
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Something down in this area smells like pancakes. This is between two of the three cards.
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Strangest. Flapjack. Ever.

Thanks to Shane Toven for revealing the likely underlying cause of all the failsauce: cooling!

Evertz 7700 frame: cooling is via two small fans on the back.
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Newer 7800FR-QT frame: this is apparently the low noise version. The 7800FR has the same design as above but the -QT gives you this wonderful front panel:

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It's like a gust front in your rack.

Guess which one I like better? 😉

My pokemans, let me show u them

Preparing for renovations of the engineering office here at work. I just got my bench and organized it aaaaand it’s gone– gone to get bigger and better. Oh well. Here, have some random nonsense.

I want to make a little collage of any ICs I find that were made the same week I was born. Some of the Z80 peripheral chips below are close but no cigar. They’re the right quarter, but a few weeks off.

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Wild 741 appeared
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Z80 peripherals
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SGS fabbed in Italy???
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RCA amplifiers still in service, using germanium transistors
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Spaghetti Junction
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I heard those things are awfully loud...
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The sunset in North Bay Village
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Frank and beans.

Your guess is as good as mine (random tech shitpost)

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No clue what this supplied power to, it’s above the telco room door. Curious ballast resistor on right. Cap is rated 200vdc. Rectifier tube is, uhh— a rectifier tube— I didn’t look
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Blowdown controller for HVAC water system, I guess. (Prevents excessive buildup of minerals in water from evaporation)
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Twinax. TWINAX.
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Old Western Electric gear
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The creme de la WTF? Barber Colman Micro 8000 automation system…. SPEAKER WIRE ran from it to each HVAC thermostat and— I’m… not sure I even want to know…
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Line printer. lp0 is thankfully not on fire
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I wonder what the print mechanism looks like?
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I have no idea other than… this… is the most ratchet looking piece of HVAC gear I’ve ever seen. I think it’s used for heating via hot water? The blower was running.
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Tellabs program amplifier card in a really neat RF shielding enclosure… that someone forgot to slap the lid on…
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Would you like to play a game? It’s called “don’t break the ceiling tile” I probably washed five pounds of tile out of my hair that night
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This stripper works great on the jacket of cat5 cable and will only set you back $70. Wait, what?
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〜 a e s t h e t i c 〜
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𝓲𝓽 𝓼𝓸𝓾𝓷𝓭𝓼 𝓵𝓲𝓴𝓮 𝓭𝓸𝓷𝓰𝔃𝓵𝓸𝓵
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Thrift store find for $5.. It works! Batteries do not go onboard; it uses an external charging supply and household plug style sync. Gold spot on the right is a very very gold plated photodiode used for auto metering. Capacitor reformed after a few shots and annoyed the staff of the thrift store who begged me to stop testing the thing and just buy it and get out of there

Anyone know where I put my MU cables?

“All mentions of the word ‘chameleon’ should be preceded by five commas. In all other instances, they come and go.” – @FakeAPStylebook

Now this is why you don’t let me play with your model trains. They wind up with gnaw marks.

This one needed to be put on a track where it moves forward when triggered by a sensor, then moves back.

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I had two options here:
A) interface to the locomotive’s onboard controls and use extra sensors and aaaaaaaaaaaaaaaa—–
B) simple DC control using relays and diodes

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Oh my glob it’s busy in there

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The motor has a tachometer sensor – I guess you can really tell it “okay, go scale speed of 79″…

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Yaaaaccckkkk. Wire nutted leads go to chassis ground and third rail.

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One of the drive motors and the smoke machine

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Bro, do you even vape? (I opened it to see what the motor was all about. It’s a fan to propel the smoke upwards.)

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One of my favorite Arduino clones, and the relay board. This controls two identical train setups. One relay on each side starts and stops the train, the other sets the direction.

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Leftover parts. I removed the extra bits because it’s remarkably hard to get the top back onto the locomotive with all that in there– it kind of barely fit!! I’m keeping the harnesses as intact as possible in case anyone ever wants to reverse the modification.

The way it works: I have each track installed with a gap in its third rail.

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At each end of the line is an isolation block to stop the train. Its travel direction is determined by the DC power polarity. That being the case, I used a diode in line with each end section to essentially make it a one way street leading back from where the train just came in. The train will move until it loses power due to the diode being reverse biased, but flipping the polarity will give it power again to move the other way.

Originally I thought I was going to need more relays and other jank until I realized it just didn’t have to be that hard. 🙂

As for the title, no, I’m not just referencing the Principia Discordia again, it’s referring to the Multiple Unit cables used to control a locomotive from the cab of another leading or trailing locomotive, or from a cab car on the opposite end of a passenger train. Prepare to laugh about the fact that the Woodward Governor is basically a mechanical digital to analog converter with pseudo BCD inputs feeding a hydro-mechanical comparator to set the engine fuel rack for a commanded rpm… Cute, right?

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