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Test Equipment Anonymous (TEA) group therapy thread

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Vince:

--- Quote from: Brumby on January 23, 2022, 01:49:32 am ---It's amazing what you hear - even when you aren't listening.....


I was up late last night, fettling at my desk with the TV providing some noise.  There was some nondescript show on and I ignore these types of show with the appropriate amount of apathy for the "quality" of programming that they offer.  Ask me later what the show was about and I would likely respond with "What show?"

However, completely engrossed in what I was poking around, my attention was immediately grabbed by the phrase "1972 Oscilloscope" which clearly penetrated my bubble of indifference to the outside world.  I quickly hopped up to see what this device could be only to see it for less than half a second.  As I watched, they never went back to it.

Nevertheless, I just had to know what the scope was - so I tracked down the show and registered for the TV station's online service so I could see the show ... and I was able to get this shot of the scope:



I can't remember EVER seeing an oscilloscope featured on TV before - for it's own sake.  Yes, lots of times as set decoration, but never like this.

--- End quote ---

Wow cool but... do you mean you PAID to get access to that show just to see the scope ?!  :scared:
You must be rich !  ;D

So what kind of show was it then ?

The kind of show where people have to guess the price of items, and the guy that's closest to the price wins something ??
Or maybe the kind of show where people bring their old stuff and a panel of antique dealers bid on it and the guy makes some money this way ?

Do tell... you wet our appetite now... you can't let us down...

Zucca:
posted here:
https://www.eevblog.com/forum/chat/22-year-old-builds-chips-on-his-garage/

at the end nice shots of TEA.
https://youtu.be/IS5ycm7VfXg?t=303

cyclin_al:

--- Quote from: mnementh on January 22, 2022, 06:56:15 pm ---
--- Quote from: mansaxel on January 22, 2022, 11:38:11 am ---
--- Quote from: mnementh on January 22, 2022, 03:10:04 am ---And so... here I am, on the other side...   After several rounds of poking around dusty, cobweb-entangle floor joists and crawlspaces, I finally figured this crazy little bastard out. <snip> But now comes a whole new misery: Each half of this duplex is connected to a different breaker. Thankfully, both on the same rail so no 240V differential, but I don't know of any GFCI outlet that'll do 2 circuits in one duplex. :o
--- End quote ---
That would be SO "illegal" in that it violates the assumption of least surprise. Not illegal per se: I just spent some time reading the swedish law, and the by public administration released regulations, that are binding like law, just easier to change.  If you deviate from the Swedish standards (which are neither law, nor regulations) you must document how, why and when the deviation was made, and I guess you must motivate why.

A duplex outlet in Sweden, by design, never can be wired separately; there are bars connecting the two receptacles. A quadruple can, but it is frowned upon.

I would put up two quadruples (in boxes, not recessed), one per circuit, mark them as such and be done with it. That would be least surprising, which is a Good Thing. This being a rental, I'm quite aware of your hands being tied at times, but at least here, the responsibility of the contractor (by law! this is what the law mostly is concerned with) is such that they will sometimes be forced to perform corrective actions on electrical installations to be free of liability.
--- End quote ---

I know I addressed this already, but...

The odds are that the contractor who did these is long-dead, and I believe at one time it was supposedly considered acceptable to use the box to connect the ground conductors as done here. :-//

As for the outlet itself... I actually did have a wild hair notion to do something similar in a single oversized 2-gang box. But then I realized all the misery I could be in for if I made such changes, and decided it was better to limit my own personal exposure. ;)

mnem
 |O

--- End quote ---

Doing something with a 2-gang box was one of my initial thoughts as well, which I will not bother to describe now.  What I was thinking does NOT match Dwagon's scenario.

Here in the GWN, it is common to make one receptacle switched as Dwagon described. 
However, we also have another scenario called "split receptacle" to provide MOAR POWER ... !  (In a normal circuit, the total circuit can only supply 15A at 120V.)
This was used typically in kitchens or workshops/garages where high-current appliances might be used.
On the duplex receptacle, the hot bus-bar tab could be snapped off to separate the two receptacles.
Then one receptacle would be wired Live1-N and the other would be wired Live2-N.  That allows you to plug in a 15A 120V appliance in EACH receptacle, which would appear to provide 30A.
It was sold as a cheap option, as it required only 3 conductors L1, L2 & N in a single cable (rather than using 4 conductors in two separate cables for L & N and L & N).
Back at the breaker panel, a 15A at 240V breaker would be used (again, cheaper than two 15A at 120V breakers).
As Dwagon mentioned earlier on this topic, it could be possible to see 240V at the receptacle if anything went wrong.
Common ways for it to go wrong involve water (like in a kitchen) or automatic dust collectors (that sense current in another circuit that supplies the tool).
Another way is connecting something powered by one 'side' of the circuit to something else powered on the other 'side' of the circuit in an electronics lab...

As an aside, I think I just gave myself an answer to my question back when Zucca and I were discussing differences between EU and NA breaker panels...
(in NA, choose breakers carefully and choose position in the breaker panel to avoid an unexpected 240V differential in the lab!)

Nowadays, the GFCI outlets do not work with the "split receptacle" scenario.  The most powerful option is to wire the GFCI duplex receptacle to a 15A at 120V breaker.  Actually, new construction has the GFCI protection built into the breaker (or arc fault AFCI or both together DFCI), rather than built into the receptacle.
People like my parents expect the "split receptacle" scenario so they get confused when they plug in two high-current appliances into the receptacle and wonder why the breaker tripped...

TERRA Operative:

--- Quote from: xrunner on January 23, 2022, 12:24:02 am ---
--- Quote from: Specmaster on January 22, 2022, 11:51:31 pm ---
So then it just me and my apprentice had to tackle the job over the next few months between us, and we uncovered many horrors along the way, lead cables, ...

--- End quote ---

Lead cables? Well I had never heard of that before. Can you describe these a little more if you remember? So heavy - how were they encased?

--- End quote ---

In Australia you used to get lead sheathed telephone cables.
Paper wrapped conductors (IIRC) inside a lead tube. Always interesting to come across in older homes, the inner conductors were still copper so it was the usual story for terminations.

TERRA Operative:
WINNER WINNER, CHICKEN DINNER!  :clap:


I decided to call it a night at 4am after losing colour across multiple CRT's/Shutters, CRT driver boards and main processor boards.
Came back today, put it together and it works! I must have forgotten something in my bleary eyed, 4am daze, but I can't remember what....  :-DD

Now to run it through a few SPC self calibration procedures to check it doesn't fail and maybe update the firmware if the later 784D firmware will work. (It'll stay as a 754D for now, but firmware is common depending on board revisions. It's easy to flash and try and flash back if no-go, just time consuming).

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