EEVblog #1334 - Mystery Dumpster Teardown

Mystery dumpster teardown time!
With the most amazing mechanical mains power switch you'll ever see!

00:00 - Playing Around
10:00 - Teardown
14:00 - OMG that power switch!
20:40 - PCB Lesson for noobs

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[abhijithanilkumar]

For every electronic hobbyist, throwing away such a beauty is a sin

[dent]

We used those in pharma research lab where we might have 20-30 environmental chambers that we needed to track and have permanent record of their temp and humidity for drug approval submissions. The dot matrix allowed you to print the drug number beside the trace and they typically recorded every minute or so. Folded chart paper was preferred because it stored in the paper file folders easier!

[rubusroo]

we used something similar in the 90's when we reconditioned & rebuilt diesel marine engines for winches/pumps/generators etc. They were used in gas & oil rig offshore installations & the criteria for acceptance was very tight & we had to produce evidence of temp monitoring for practically every component during the run in process. The units would have to run for in excess of 100 hours at set RPM & every facet of the unit performance had to be demonstrated else it was rejected & rebuilt even if it was brand new. This was a company called ARS limited Loddon, Norfolk UK.

I should add that the unit we used monitored & recorded vibration too & was part of the engines "passport".

[impalatube]

These are still very popular in the pharma manufacturing industry for recording multiple temperature probes during steam sterilisation cycles of sterile filling machines.

Pharma manufacturers are audited annually by government regulators. And those auditors love their paper records.

I can 99% guarantee that if it came from a pharma site it will have been replaced with another newer dot matrix printer.

[knutstitan]

Fun fact: you can average the signal (assuming it's not AC) by cutting it out and weighing it and dividing by the weight of a whole (full scale) piece of the same length. This is how they used to take the mean in the "old days".

[nagisaayanami]

I remember this thing.. Used to have one for petroleum cracking. Each lead could tell you the internal temperature of the product at various stages (channels) of the process and it would plot each channel over time.

[derkeksinator]

I haven't seen this mechanical solution on a simple power switch yet. However I do have an old Technics amplifier that uses the same type of ribbon for the input and recording selectors, which makes sense in order to keep cables short and thus noise out.

[martinda]

That was great...Just listened to your interview with Louis Rossmann, oh man, he really has become such a wonderful character - Just like our Dave!
I say that because I've watched him since he started and sort of feel proud for him, watching him grow into the person he is. Very gratifying to see.
We could tell you thought he was a good chap to have on. Was a great Amp Hour.

[electronash]

14:48 I don't remember what they are called, but I've seen almost the same type of transfer belt switch in certain HiFi units / radio tuners.

They used to use them for the multi-pole switches on the front panel, to reduce the amount of wiring around the chassis, and supposedly reduce the noise.

[Havensal]

I believe the two "B" terminals are for 3-wire RTD's. They have two wires going to one side of the sensor element so the machine can measure the resistance in the lead wires and subtract that from the total resistance. This gives the actual resistance of the sensing element for a more accurate reading.

[GiddeonFox]

Leave it to Dave to see this wonderful electromechanical marvel and go "Ok that's cool and all, but wait 'till you get a look at the power switch!" :)

[AnalogThinker]

Those steel belts are fairly common in older receivers or audio equipment (input selector, speaker A/B selection...) but don’t know what it’s called

[Zardox-The-Heretic-Slayer]

back when I was a (late) teenager, I worked in a steelworks (although it dealt with other metals) briefly and we had versions of these things. I used to take the broken ones home to salvage parts from

[Gameboygenius]

I read the video description before watching the video: "With the most amazing mechanical mains power switch you'll ever see!" and I thought at first that it was just a very snarky reference to the fact that the power switch was inside the front panel. I was not disappointed when I saw what it was actually referring to though.

[josephmazzeo]

I wish I had a dumpster like yours...the only items in my dumpster look like bio-hazard waste.

[Namirred]

The roller appears to be the door catch.

[kevincozens]

Who else thought Dave should have turned the LCD Adjust knob the moment he commented on how hard it was to read the LCD screen? At 21:22 there is indication that the encased inductor had its designator on the PCB but the board designer didn't take the packaging in to account and ensure the label would not get hidden under the part.

[rfmerrill]

You read "TC" as "temperature compensation", it's probably "Thermocouple" since it says "KIND" next to it and "K" on the other side.

[KaizerPowerElectronicsDk]

18:36 that was nice, just pulled a card from a analog x-ray image processor and it has these LC filters near the DC-DC converter, at first glance I just wondered why the SMD capacitor was elevated. That card also has some really interesting input noise counter-measures, I will make a video about that.

[mauriziomiserere]

The mechanical linkage to the power switch is very common in Japanese hifi components for switching inputs, filters, speakers, and more. Luxman really liked to use those linkages in their products.