Test Equipment Anonymous (TEA) group therapy thread

[mansaxel]

So the takeaway here is... it isn't just the USA suffering a hostile corporate takeover of their central and regional governments...?   

I sortakinda expected that from you

It's not a takeover, it is the legislator keeping an arms length to agreements between businesses. If you do that, they'll congregate and bully.

[Robert763]

Tracked it down to Tektronix part number 131-4619-00, 3M part number 91100-1201BP.
I found this service manual that has the info, page 110, Part A10J100

http://www.ko4bb.com/manuals/126.43.229.62/TDS520B_Mod_CM_Digitizing_Oscilloscope_Component_Service_Manual_070-9710-03.pdf

https://www.mouser.jp/ProductDetail/3M-Electronic-Solutions-Division/91100-1201BP?qs=pxWKQutMSmprHMNm7tgF9Q%3D%3D

Now to find somewhere to buy a handful without having to buy a box of 1000, if they aren't obsolete..........

Octopart lists only one distributor:

https://octopart.com/91100-1201bp-3m-12605618

Smells expensive ...

Yeah, I got an otherwise good TDS754D processor board (pending tests) that just needs one connector, and I've seen a HDD option board for sale that needs one too.

If I could just buy like 10, and the same for the mating connector (131–4618–00 / 91100–22010AR), I would be so happy...

Try asking 3M for samples. No harm in trying....

[AVGresponding]

Well now here's the thing, all the electrical contractors that I know, and over the years that number was huge, before I retired, all have to have their work inspected by an inspector who will pick out contractors to inspect at random. That inspection (Anders over to you on this, as I'm going from memory here, but you are living this shit every day), does not look at the company records but at an actual installation that either has been completed or is in the process of being carried. If that inspector finds out that it is not up to the current edition (unless its in the transitional stages between old and new editions of the IEE Wiring Regs., then there are some serious repercussions for the contractor. In a similar vein to that of a discredited doctor of medicine, who can be struck off the medical register, is there something along similar lines for the electrical contractor?

Also am I not correct in assuming that you cannot get a new supply to a new installation connected by the supply authorities if that installation does not meet the latest wiring standards, i.e., wiring regs?

The contractor would be told by the Electrical Clerk of Works to follow the guidelines as set out in the 18th edition of the BS7671 wiring code, or the work would not get signed off.

As to whether the likes of Northern Powergrid or whomever your local supplier is would refuse connection, I don't know, I don't deal direct with them. I suspect they wouldn't ask about such matters, the only thing they seem to care about is whether there's a meter installed...

[GreyWoolfe]

Nowadays it has apparently been decided that it's too difficult/expensive to educate people properly, and so make every situation as completely idiot-proof as possible. We all know where that leads...[/color][/size][/b]

It had been proven time and time again that the Universe is quite adroit at building better idiots and the Universe is improving daily.

[dl6lr]

Go add a 47uF, 80V (or more) LOW-ESR cap you your next parts order, along with 4x 1000pF (10mm pitch) X-class capacitors to replace the Rifas (double check if yours has them first, I believe the 544A PSU does...).

Replace C13 on the power supply board ASAP, it's a ticking timebomb and will take out a bunch of parts when it decides to go off.
It's a weak point and will kill your standby power, meaning a dead scope until you replace a handful of parts.

Can you elaborate on where that cap is located? I just had a glance at the PSU diagrams of the 540 and 544A and could only find a C17 47µF with low voltage in the standby PSU.

Ah, my bad. It is C17 that you want to replace, as you highlighted in the schematic.

Ah, OK, I see. Why should it be a high voltage type? In normal operations, the voltage will be low and only may rise to a higher level if any of the diodes above are open (I assume the cap failing will be a minor problem then).

[Vince]

Varta battery :

Waiting 'til tomorrow to measure battery voltage again, following Rob's instructions, but that does not mean I am inactive ! 

I am so upset about my lab power supply that's not up to the job, can't set current limit low enough for the task at hand, and can't even monitor current,  not enough resolution on the display.

I want a better supply !!! One day.....

In the mean time I thought hey ! Why not use that as an excuse to make my own little constant current charge/discharge circuit ?!
Like.. using a Wilson current source, say ?! That would be fun !

So I looked at the trannies I had in stock, found some TO-39 2N2905A, checked the datasheet, looks plenty capable enough for my modest need here.

So picked 3 of these and wired everything up on my breadboard. Current can be set with a pot from 3.7mA to 13,5mA.  Battery is 110mAh so C/10 is 11mA. So I wanted to be able to adjust it around 10mA.

First time I make a Wilson mirror I think, was excited to see if that would work, it's quite magical... and it does work   
It's so cool, just turn the pot and hey presto you can control the output current.

I used my brand new Metrix MX554 bench meter to monitor output current, of course 

So tomorrow, once I have measured the battery voltage, I will be able to discharge it in a controlled manner... then charge it again in total control... how cool is that ?

Only thing I am not too sure about, is the current "mirror" is a twisted mirror.... output current is a bit higher than asked. Like, to get about 10mA or so at the output IIRC, I had to set the input current lower than that, 8.75mA.... is that "normal" / expected with that kind of circuit ? Or is just that my trannies are so old that one is very low on Beta, and/or there is a big Beta mismatch between the 3 trannies and that screws things up ?



It's so cool what you can do with just a handful of components !

[xrunner]

It's so cool what you can do with just a handful of components !

Vince that's really cool. Someday you'll be restoring oscilloscopes, I sure of it. 

Over here I received the book covering film and 67 lb gray paper. I did a little more fine-tuning of the document, and printed a test on the paper going with bold text (after that pic). Looks good to go so I'll proceed to trimming and final attachment with the film. I'm going to put it right over the top of the original sticker preserving it underneath. 

[BU508A]

Vince that's really cool. Someday you'll be restoring oscilloscopes, I sure of it. 

Or a 576 curve tracer from Tektronix.

[factory]

Test. Can everyone see this? 

Thankfully I can't on the phone, linked eBay pictures haven't worked on mobile version of Firefox for a long time too.
I suspect it's because of uBlock, ADP got borked by a major Firefox addon code change years ago and I never went back.

The PC is still running Firefox & ADP though, might have to add a custom block for papasmurfs unwanted image.

David

[factory]

Go add a 47uF, 80V (or more) LOW-ESR cap you your next parts order, along with 4x 1000pF (10mm pitch) X-class capacitors to replace the Rifas (double check if yours has them first, I believe the 544A PSU does...).

Replace C13 on the power supply board ASAP, it's a ticking timebomb and will take out a bunch of parts when it decides to go off.
It's a weak point and will kill your standby power, meaning a dead scope until you replace a handful of parts.

Can you elaborate on where that cap is located? I just had a glance at the PSU diagrams of the 540 and 544A and could only find a C17 47µF with low voltage in the standby PSU.

Ah, my bad. It is C17 that you want to replace, as you highlighted in the schematic.

Ah, OK, I see. Why should it be a high voltage type? In normal operations, the voltage will be low and only may rise to a higher level if any of the diodes above are open (I assume the cap failing will be a minor problem then).

Maybe to get a similar size can to the old capacitor? Definitely had problems at work with SMPS & tiny modern caps, someone specced one the same voltage as the original, but the tiny cap overheated & blew rather quickly on test.

David

[Vince]

Carlson just released yet another video on another cool super old nixie HP counter, looks nice !

[cyclin_al]

Test. Can everyone see this? 
.. [snipped for everyone's sanity

No !  No ! No !

However, I just knew it was coming.  I was certain that our fate was sealed as soon as I read this:

[lots of snipping] even the ones I don't want to see!

A sign of true TEA membership is the ability to predict when *that* is going to show up...
 

[mnementh]

So the takeaway here is... it isn't just the USA suffering a hostile corporate takeover of their central and regional governments...?   

I sortakinda expected that from you

It's not a takeover, it is the legislator keeping an arms length to agreements between businesses. If you do that, they'll congregate and bully.

Well... it sortof sounded more like the usual "business as usual". Whenever there's a question of actual human safety, eventually the corporate drones make the process such an unmitigated fustercluck that there's no option but to turn it into something that gets outsourced to another corporate entity.

And now, where we once had actual regulation and inspections from some government authority that at least in principle is there to protect the public, we have a world full of corporations being "watched" by other corporations, and the regulators are being told by the corporations how they are going to be regulated.

mnem
This will end well.

[DH7DN]

Carlson just released yet another video on another cool super old nixie HP counter, looks nice !

Mixed feelings about this. On the one hand, it's Test Equipment in perfection... 70 year old and still working, highly repairable and it will probably survive me and few others 
On the other hand... bulky design, very fragile, consumes a lot of power, limited measurement capabilities compared to modern standards...

I enjoyed this video  But it's not my rabbit hole 

[mnementh]

Nowadays it has apparently been decided that it's too difficult/expensive to educate people properly, and so make every situation as completely idiot-proof as possible. We all know where that leads...[/color][/size][/b]

It had been proven time and time again that the Universe is quite adroit at building better idiots and the Universe is improving daily.

The Universe is about building galaxies and nebulas and stellar nurseries and shit. Idiots are a "humanity" product, through and through. The universe couldn't care less about any of us; any more than we care about the 11,387,429th cell in our big toe.

mnem
*toddles off to do.... something.*

[Vince]

It's so cool what you can do with just a handful of components !

Vince that's really cool. Someday you'll be restoring oscilloscopes, I sure of it. 

Are you talking about the 502A ?! 

Sorry, other priorities ! 

I want to keep digging out and sorting and organizing all my electronics stuff first, because it takes a lot of time to go through all these boxes of stuff, most being very hard to get to, because no space. Work on my bedroom has now be resumed, as yesterday I finally received my parquet. So now I need to install that. Then the plinths. Then I can switch from sleeping in the living room / lab, to sleeping in an actual bedroom. Once that's done the lab will be able to expand a bit and I will at last have space to organize the lab properly, for active operation... not just a huge storage area full of boxes full of random stuff.
Sorting all the stuff takes time.. so I want to do that now, so that once the bedroom is finished, the lab can be operational quickly. Don't to finish the bedroom then spend a month prepping the lab.

So, once the bedroom is finished and the lab operational.. then yes I will happily resume work on the 502A ! 

Over here I received the book covering film and 67 lb gray paper. I did a little more fine-tuning of the document, and printed a test on the paper going with bold text (after that pic). Looks good to go so I'll proceed to trimming and final attachment with the film. I'm going to put it right over the top of the original sticker preserving it underneath. 

No not good to go !!  You forgot the fine tuning :

For starters you forgot to insert a blank line between the Title at the top, and " STEP " .  Also not enough spacing above and below the ruler at the bottom.
Fonts for the button caption is a tad too small as well, especially the " dBm".

But the print as such does look nice on that paper... looks better than the original silver metallized plastic film... have never been a fan of these things...

[Vince]

Vince that's really cool. Someday you'll be restoring oscilloscopes, I sure of it. 

Or a 576 curve tracer from Tektronix.

No no no, you meant 575 for sure ! 

It's a 575 I got.... no 576 here, and no plan on getting one either.

[xrunner]

No not good to go !!  You forgot the fine tuning :

I want all the guests out there to now realize: This is what I have to deal with here!  Come on in the water is fine. 

For starters you forgot to insert a blank line between the Title at the top, and " STEP " .  Also not enough spacing above and below the ruler at the bottom.

That was a compromise on the spacing of the entire sheet, but sure if you think it's better I'll insert space.

Fonts for the button caption is a tad too small as well, especially the " dBm".

No not this time Vince - it is the exact same font size. It's an illusion because the "d" and the "m" are the only lower case letters used in the annotation of any of the buttons and it makes this one look wrong, but it isn't! 

But the print as such does look nice on that paper... looks better than the original silver metallized plastic film... have never been a fan of these things...

Whew!!! 

[tggzzz]

Nowadays it has apparently been decided that it's too difficult/expensive to educate people properly, and so make every situation as completely idiot-proof as possible. We all know where that leads...[/color][/size][/b]

It had been proven time and time again that the Universe is quite adroit at building better idiots and the Universe is improving daily.

Old engineering adage: you can't make something foolproof because fools are so damn ingenious. I'm sure we all have anecdotes in that vein.

[Vince]

No not good to go !!  You forgot the fine tuning :

I want all the guests out there to now realize: This is what I have to deal with here!  Come on in the water is fine. 

For starters you forgot to insert a blank line between the Title at the top, and " STEP " .  Also not enough spacing above and below the ruler at the bottom.

That was a compromise on the spacing of the entire sheet, but sure if you think it's better I'll insert space.

Ah, you mean you were trying to make your reproduction exactly the same height as the original ?!
How cares if it's half an inch longer !    I find it more important to make it look good, more than it is to make it 100.0000% the same size.... but that's just me ! 
And it's not MY meter it's yours ! 

Also, depends on your particular word processor but normally one can adjust the line interval. Maybe this feature might give you enough fine control, pixel by pixel. That would help you keep teh overall height of the document under control, while still adding space where discussed earlier ?!

[tggzzz]

Go add a 47uF, 80V (or more) LOW-ESR cap you your next parts order, along with 4x 1000pF (10mm pitch) X-class capacitors to replace the Rifas (double check if yours has them first, I believe the 544A PSU does...).

Replace C13 on the power supply board ASAP, it's a ticking timebomb and will take out a bunch of parts when it decides to go off.
It's a weak point and will kill your standby power, meaning a dead scope until you replace a handful of parts.

Can you elaborate on where that cap is located? I just had a glance at the PSU diagrams of the 540 and 544A and could only find a C17 47µF with low voltage in the standby PSU.

Ah, my bad. It is C17 that you want to replace, as you highlighted in the schematic.

Ah, OK, I see. Why should it be a high voltage type? In normal operations, the voltage will be low and only may rise to a higher level if any of the diodes above are open (I assume the cap failing will be a minor problem then).

Maybe to get a similar size can to the old capacitor? Definitely had problems at work with SMPS & tiny modern caps, someone specced one the same voltage as the original, but the tiny cap overheated & blew rather quickly on test.

Need to check the ripple current at the operating frequency. Something aimed at audio decoupling might not work for mains smoothing, something rated at 50Hz may not work at 20kHz.

[Vince]

Carlson just released yet another video on another cool super old nixie HP counter, looks nice !

Mixed feelings about this. On the one hand, it's Test Equipment in perfection... 70 year old and still working, highly repairable and it will probably survive me and few others 
On the other hand... bulky design, very fragile, consumes a lot of power, limited measurement capabilities compared to modern standards...

I enjoyed this video  But it's not my rabbit hole 

I never said it was high spec nor practical by modern standards (which is a totally unfair and irrelevant comparison anyway !  )... I only said it was cool and beautiful !! 

[DH7DN]

Carlson just released yet another video on another cool super old nixie HP counter, looks nice !

Mixed feelings about this. On the one hand, it's Test Equipment in perfection... 70 year old and still working, highly repairable and it will probably survive me and few others 
On the other hand... bulky design, very fragile, consumes a lot of power, limited measurement capabilities compared to modern standards...

I enjoyed this video  But it's not my rabbit hole 

I never said it was high spec nor practical by modern standards (which is a totally unfair and irrelevant comparison anyway !  )... I only said it was cool and beautiful !! 

That's true, the comparison is a bit unfair   Let's just appreciate its beauty, elegance and 1950's engineering perfection! 

[Cubdriver]

Carlson just released yet another video on another cool super old nixie HP counter, looks nice !

A 521D has been in my search list for a long time - never knew it came in a rack mount version, too, but I suppose that should be no surprise...

On another note, the 5340A is now apparently BACK in North Billerica, MA as of 6:15 PM today; this after being 'in transit' from Billerica from around quarter after five this morning.  They now say it will be delivered tomorrow, but after promised deliveries on Wednesday, Thursday and today I'm not giving that prognostication very much weight.  Apparently the three stooges have taken over FedEx.  I'm praying that it was packaged well...

-Pat

[mnementh]

   And So... It Begins.   Pressed the eldest into service today; we did a little clearcutting in preparation for trying to build my workbench space in the dwagon-cave.

   First step once the clutter was hauled off is to get power situated with a GFCI outlet for my TE. 30 seconds into that and...    "Oh cheet, mang..."   A few more minutes of investigation revealed that the top outlet of the duplex is broken out and evidently switched from Ifni knows where the fuck all...

   ...and the lack of ground is evidently widespread and systemic (I can see at least 3 distinct "layers" of electrical work from different eras here), as pretty much every junction block in the basement with the same type of ROMEX run to it as that outlet looks like this.

FML.

mnem

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. Originally I thought from the way the Duplex was wired that one outlet was switched from some effing place else in the house I just couldn't find. But after triple-checking the wiring to the side that did light up, I decided to pull these      grounding horrors apart and after testing with my trusty FieldPiece  HVAC DMM, I twisted all 4 grounds together to see if it resolved the open GND, which it did.

That immediately brought another head-scratcher; the other outlet now lights up but shows OPEN NEUTRAL. 

After easily 30 minutes tracing out the other circuit, it finally dawns on me to test the effing outlet with my meter instead of just trusting my Noid-lights. Sure enough, damaged contact in the duplex. Please forgive the ridiculous suicide-cord test leads; they were the only thing I could get to clip on there for the pic.

So... remember kids; any time your handy-dandy xyz tester has you scratching your head... GET THE FUCKING METER!!! There is still no substitute for a good DMM and your brain!

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.

I think I've had enough joy for one night; I'm going to bed.

mnem