Test Equipment Anonymous (TEA) group therapy thread

[bd139]

Most sparkies I deal with are colour blind or don't give a fuck apparently anyway so I'm not sure it's going to change the status quo in any way

[tautech]

Downunder in NZ
Single phase
Phase Red
Neutral Black
Earth Green/yellow

3 Phase
Phases Blue, White, Red,
Earth Green/yellow

However Flex cables can be different with Brown and Blue for phase and neutral in single phase leadout cables.

Much better 3-phase colours than the new dull colours (black/brown/grey) we were forced to change to (though we had yellow instead of white). 
It makes you wonder how many mistakes are made (or will be in future) when cables end up dirty & illegible.

David

Yellow is sometimes used for phase in 3 ph too here. 

About the 2 pole mains Black and Blue you mentioned, obviously a UK sparky couldn't bring himself to use the Black for phase as the US do so used the Blue like you would for 3ph. 
Sorta makes sense for us that don't use Black for phase. 

[capt bullshot]

Never mind that colour coding stuff. Electrons are colour blind and won't stop electrocuting you based on the sleeve colour of a wire :-Þ

[factory]

Downunder in NZ
Single phase
Phase Red
Neutral Black
Earth Green/yellow

3 Phase
Phases Blue, White, Red,
Earth Green/yellow

However Flex cables can be different with Brown and Blue for phase and neutral in single phase leadout cables.

Much better 3-phase colours than the new dull colours (black/brown/grey) we were forced to change to (though we had yellow instead of white). 
It makes you wonder how many mistakes are made (or will be in future) when cables end up dirty & illegible.

David

Yellow is sometimes used for phase in 3 ph too here. 

About the 2 pole mains Black and Blue you mentioned, obviously a UK sparky couldn't bring himself to use the Black for phase as the US do so used the Blue like you would for 3ph. 
Sorta makes sense for us that don't use Black for phase. 

But we now do use black for a phase, makes me glad I'm not a sparkie.


David

[tautech]

    

[med6753]

Most sparkies I deal with are colour blind or don't give a fuck apparently anyway so I'm not sure it's going to change the status quo in any way

And then you have the dip shits who THINK they are sparkies. This individual decided to install the outlets with the ground prong up. That in itself is no issue and in fact in some areas is required. Now doing that you have to reverse your thinking. The "Hot" prong is now on the left rather than the right. Nope...he wired all dozen or so outlets backwards and had been that way for several years until I discovered it one day when an outlet went dead. (He used the should be illegal "push in" tabs rather than the screw terminals)   

[med6753]

   

Agreed...holy shit. 

[tautech]

   

Agreed...holy shit. 

Obviously dreamed up by some FW that only ever polished a chair with their arse !
Dumb, just plain dumb ! 

[factory]

Most sparkies I deal with are colour blind or don't give a fuck apparently anyway so I'm not sure it's going to change the status quo in any way

Yep they don't give a fuck in the north of England either, a newly trained 'passed the one day course' gas boiler service guy from a major provider kept connecting the green earth wire to live and wondering why the fuses/breakers kept blowing. 

Plus I gave up trying to explain transformer inrush current (no soft start fitted) & circuit breaker tripping to a useless contract sparkie at work, all we wanted was the transformer fed from a different breaker to the computers & server.
He also though that all the low power TE (several bench multimeters, signal gen, low voltage PSU and oscilloscope) connected to one socket (via a fused socket strip) was going to cause an overload & start a fire, if that was true the lab would have burnt down decades ago. 

David

[bd139]

LMAO that’s about right. I have a friend who is a sparky and I fixed his DMM, a big Megger tester. Battery had leaked in it about a year before and he never used it on a job. Needed to get it calibrated to tick a box ffs. I also fixed his Xbox 360 which he’d not covered up while doing major decorating work and it was crammed full of plaster dust. He was going to throw it away. All I did was dismantle it and hit it with the hoover ffs.

That’s the mindset.

Edit: and then there’s the heating engineer who nearly blew us up. Could hear clunking when he did yearly inspection. So I went and looked and he was hitting the main gas valve with a wrench because it was stuck. He was whacking it the wrong fucking way and caused a leak. I kicked him out and called the gas emergency number and they came out within the hour and replaced that and the entire meter because it was damaged where he’d missed with the wrench.

[mansaxel]

Now doing that you have to reverse your thinking. The "Hot" prong is now on the left rather than the right.

Actually, you'd have to reverse your thinking somewhere between 50 and 60 times per second.  For all single-phase + neutral work, it is much easier to just assume that any wire not green/yellow (or in US, green) is live. (In Norway, or onboard ships, this is essential, because they are live! This because they run 220/127V three-phase but without a neutral, so all loads, even your desk lamp, are Delta connected). Constructions (like live chassis) that depend on the position of phase and neutral are just death-traps anyway.

/Måns, Schutzkontakt (CEE 7/4) for ever!

[med6753]

Now doing that you have to reverse your thinking. The "Hot" prong is now on the left rather than the right.

Actually, you'd have to reverse your thinking somewhere between 50 and 60 times per second.  For all single-phase + neutral work, it is much easier to just assume that any wire not green/yellow (or in US, green) is live. (In Norway, or onboard ships, this is essential, because they are live! This because they run 220/127V three-phase but without a neutral, so all loads, even your desk lamp, are Delta connected). Constructions (like live chassis) that depend on the position of phase and neutral are just death-traps anyway.

/Måns, Schutzkontakt (CEE 7/4) for ever!

Over here you NEVER assume a white wire is neutral because in some special cases it can be hot. Sparkies who don't catch on to this fact are dead. 

[AVGresponding]

Wow, where to start lol...

Well, the confusing UK wiring colours are due to EU harmonisation rules, which raises the prospect of a return to red/yellow/blue when (if) we leave...

As for considering all conductors aside from earth as live, the current regs (IET 18th edition) do indeed do that; neutral is a live conductor, what we used to call 'live' is now called 'line'... and so we have line 1, 2, and 3  (brown, black, grey) 

@factory, the markings on the DP isolator are not reversed; the numb-nuts that installed it decided to use the colours from the 3 core armoured that supplies it thusly: blue = line, red = neutral, yellow = floating, armouring = earth.
I would have done some shouting at him. That doesn't sound too bad, until you realise I have a sar'major level voice.

@lowimpedance, sorry, mine doesn't have the RMS module fitted.


Oh, and also... please...

slap

ME

upside

THE HEAD


Repeat after me:

Thou

SHALT

measure

VOLTAGES!


After reseating the ICs in the 1905, I had no change, still glitchy af.

THEN numb-nuts here decides to measure VOLTAGES...

+15V rail was 0.05   

Pulled the 78L15 and still measured a dead (0R3) short, so set about chasing it down.

After a few minutes, found this:

Which looks like an exploded tant, but was in fact just solder splash... nevertheless, this 10uF 16V tant once removed, proved to be the short. It was one of a pair of decoupling caps for the +/-15V supply for an op-amp.
Didn't have any 10uF caps to hand, so popped in a couple of 22uF low ESR electros I had spare from a car audio amp project.

Ta-daaa!

As you can see, it's not a million miles away from my recently cal'ed 8840A, so happiness is restored.
Though I would question the usefulness of the readings on the 'secret' 6.5 digit mode... think the Fluke is likely more accurate with 5.5 digits.


Finally, an amusing mistake by Rapid Electronics:

The red shrouds are meant to be the same size as the black ones, seems they have been exposed to an embiggening field!

[med6753]

Hey dumb ass....measure the bloody voltages. 

I just needed to bust your balls.....good deal! 

[Specmaster]

   One for the UK sparkies; what's wrong with this picture?

That is made up unit from other bits and the problem there is that the breakers are being fed from a top mounted busbar which has Merlin Gerin isolock isolaters with the tabs hanging down with no safety shields in place.

So... the three conductors of unknown state just hanging outside the box... not a problem...?

mnem
*tzzzt*

No problem at all except for the totally wrong color coding for a single phase installation. 

Tautech wins the prize   

Interestingly, the numpty that installed it decided to use the red in a 3 core as the neutral, under that MC Hammer-esque baggy black sleeving, and what did they do with the yellow conductor? They cropped it at both ends of course, leaving a floating conductor in the cable.   

@Specmaster, all the parts are Merlin, none of that Schneider rubbish    and the reason there are nakey busbars showing is that it's in the process of being decommissioned. The only reason we livened the board back up was to get a temp supply to an area where we needed 240V for a tool tranny.

@mnem, the conductors in question are the temp I was putting in; don't worry, I DID sleeve them with the correct colours, and did NOT leave any floating conductors.   


@lowimpedance, thank you greatly for your post. The plot thickens!
Your processor board looks to be the same rev as mine; the one in the manual is (I believe) an earlier one, with 2x 2114 instead of 1x 6116 SRAM, and a 74LS155 instead of the 156 (although the parts list shows a 155 and not a 156, so maybe a typo? They're both multiplexers anyway).
This EEVBlog thread has a possible clue; post 3 leads me to believe that reseating the ICs is my next logical step, and not forgetting also the first commandment "Thou shalt measure voltages".

Well the colour of the cables exiting the enclosure, I discounted because they were not connected and I assumed that the board was live and the busbar was as you said, "nakey" and that is just not acceptable. the colours of the cables was not an issue because there were not connected and so was impossible to tell if they were part of a multicore and had been pulled out and not being used, pending chopping or coiling up / sleeving. There was not much of a clue as to what was going on there at all.   

[worsthorse]

well, it looks like my 8840A and 8840A/AF may be parts mules after all.  i pulled the display boards out of both of them. 

here's why the display doesn't light up on the 8840A:



I am guessing this box got dropped hard on a hard surface at some point and when the display stopped working it was scavenged for parts, which is why it is missing all the micro-controller logic ICs, an A/D IC and one of the Fluke custom ICs. 

and here's (at least one reason) why some of the buttons on the 8840A/AF don't work:



I checked the resistance across the switches and its mostly in the 20K range in the bad board and the 900 ohm range on the good one. The 8840A/AF has some problems in the current reference, too, and is consistently failing all of the DC side self tests.

Soooooo, I could assume that the 8840A actually worked until the display got busted and move parts from the flaky A/AF, along with tearing apart the two display/keypad modules and making one good one from two bad, and see what happens. Or I could buy some conductive paint and try to fix the matrix on the keypad and avoid the desolder fest. But that sounds like a lot of work when I could probably part them out (there are lots of good parts left in each), make back ten times what I paid for them, and buy a working 8840A with the VAC option.

[mnementh]

   One for the UK sparkies; what's wrong with this picture?

That is made up unit from other bits and the problem there is that the breakers are being fed from a top mounted busbar which has Merlin Gerin isolock isolaters with the tabs hanging down with no safety shields in place.

So... the three conductors of unknown state just hanging outside the box... not a problem...?

mnem
*tzzzt*

No problem at all except for the totally wrong color coding for a single phase installation. 

Hey... two (one...? Is that yellow or yellow/green?) out of three ain’t bad. 

Maybe you know somehow I don’t... are those wires actually connected to something hanging outside the box...?

Visions of THAT scenario... with the cover left off as a result... were the reason my initial reaction was more 

mnem
*zzzorch*

[mnementh]

....The only reason we livened the board back up was to get a temp supply to an area where we needed 240V for a tool tranny.

@mnem, the conductors in question are the temp I was putting in; don't worry, I DID sleeve them with the correct colours, and did NOT leave any floating conductors.   

 

Okies... temp power tap I’ll give you. I’ve had to jackleg my own fair share of short-term subpanels. 

Just so long as you put plenty of dumbass tape around the perimeter until you have everything de-energized, buttoned up & 1d10t-proof again.


mnem
3. That bodge will come back to bite you in the ass.

[tautech]

   One for the UK sparkies; what's wrong with this picture?

That is made up unit from other bits and the problem there is that the breakers are being fed from a top mounted busbar which has Merlin Gerin isolock isolaters with the tabs hanging down with no safety shields in place.

So... the three conductors of unknown state just hanging outside the box... not a problem...?

mnem
*tzzzt*

No problem at all except for the totally wrong color coding for a single phase installation. 

Hey... two (one...? Is that yellow or yellow/green?) out of three ain’t bad. 

Yellow. If you look carefully the green/yellow earth has already been terminated.

Maybe you know somehow I don’t... are those wires actually connected to something hanging outside the box...?

It just makes sense they weren't terminated off but the issue for us in NZ is why would 3ph cabling be used in a single phase board. 

Visions of THAT scenario... with the cover left off as a result... were the reason my initial reaction was more 

No worry, that was my first thought too but being a little familiar with mains wiring here you'd get shot using those cable colors here in a single phase installation so that was the clue to what was wrong.

[mnementh]

   But we now do use black for a phase, makes me glad I'm not a sparkie.

David

   

Holy Fucking ASSCRACKERS!!!  WERE THEY THINKING?!?

mnem
Probably some ignorant BS color scheme generated by some complete backbirth lobbyists because those 4 colors were somehow most profitable to some manufacturer or somesuch wank...

[mnementh]

well, it looks like my 8840A and 8840A/AF may be parts mules after all.  i pulled the display boards out of both of them. 

here's why the display doesn't light up on the 8840A:   

I am guessing this box got dropped hard on a hard surface at some point and when the display stopped working it was scavenged for parts, which is why it is missing all the micro-controller logic ICs, an A/D IC and one of the Fluke custom ICs. 

and here's (at least one reason) why some of the buttons on the 8840A/AF don't work:   

I checked the resistance across the switches and its mostly in the 20K range in the bad board and the 900 ohm range on the good one. The 8840A/AF has some problems in the current reference, too, and is consistently failing all of the DC side self tests.

Soooooo, I could assume that the 8840A actually worked until the display got busted and move parts from the flaky A/AF, along with tearing apart the two display/keypad modules and making one good one from two bad, and see what happens. Or I could buy some conductive paint and try to fix the matrix on the keypad and avoid the desolder fest. But that sounds like a lot of work when I could probably part them out (there are lots of good parts left in each), make back ten times what I paid for them, and buy a working 8840A with the VAC option.

Or you could use the money to get a nice 3478A and never worry about the display again... 

mnem
 

[worsthorse]

well, it looks like my 8840A and 8840A/AF may be parts mules after all.  i pulled the display boards out of both of them. 

here's why the display doesn't light up on the 8840A:   

I am guessing this box got dropped hard on a hard surface at some point and when the display stopped working it was scavenged for parts, which is why it is missing all the micro-controller logic ICs, an A/D IC and one of the Fluke custom ICs. 

and here's (at least one reason) why some of the buttons on the 8840A/AF don't work:   

Or you could use the money to get a nice 3478A and never worry about the display again... 

mnem
 

i could but i love these old flukes. such lovely, well-made gear.

so, about thirty minutes after i decided to part it out, i changed my mind. i figured there had to be a way to get a working DMM out of these two boxes.  so i decided to pull the ICs from the "working" Fluke into the one with busted display, install the cleaned display/keypad board, and see what happened. 

damn if it didn't work.   



maybe i will post all the intermediate photos of bench chaos later. at one point, both meters were completely torn apart and spread over the floor, so i could pick through the remains. after replacing missing parts, fixing some solder joints, and re-assembling, all the functions work, front and back connectors work and it detects that the VAC board is not installed. the display is also nice and bright. looks as good as my bench fluke. 

here it is, mostly re-assembled:



i found an option 09 board, too, which is on its way, and will bring the new meter completely up to grade.

still have to work through all the test and calibration procedures. glad i gave up on giving up on this one.   

edit: spent another thirty minutes at the bench comparing the new 8840A to the bench 8840A. from 10mV to 22V DC and from 10 to 10M ohms, it is within spitting distance. still, the self-tests indicate there's a problem in the DC section somewhere, so I will dig into that tomorrow.  but overall this looks like a win.

[AVGresponding]

Result!

Even though you had to work a bit for it, you still deserve a jammy git award   



@mnem, nope, nothing is coming back to bite me in the ass; the building is empty, the board is turned off when we aren't there, and the only people allowed in are (theoretically at least) intelligent enough not to poke their fingers into dangerous places.
I did of course replace the board cover once I'd terminated our temp.

The building is getting dropped, as soon as the (going out to tender) asbestos removal contractor has done their work.
I believe the leading bid is in the region of $500k so far, there's quite a bit of it in there as I said.

Sadly, those huge wire-wound power resistors are definitely wound onto asbestos insulated armatures, no loot for me   

[VK5RC]

@w-h, bloody brilliant, hope the dc issue isn't too much trouble

[Terry01]

well, it looks like my 8840A and 8840A/AF may be parts mules after all.  i pulled the display boards out of both of them. 

here's why the display doesn't light up on the 8840A:   

I am guessing this box got dropped hard on a hard surface at some point and when the display stopped working it was scavenged for parts, which is why it is missing all the micro-controller logic ICs, an A/D IC and one of the Fluke custom ICs. 

and here's (at least one reason) why some of the buttons on the 8840A/AF don't work:   

Or you could use the money to get a nice 3478A and never worry about the display again... 

mnem
 

i could but i love these old flukes. such lovely, well-made gear.

so, about thirty minutes after i decided to part it out, i changed my mind. i figured there had to be a way to get a working DMM out of these two boxes.  so i decided to pull the ICs from the "working" Fluke into the one with busted display, install the cleaned display/keypad board, and see what happened. 

damn if it didn't work.   



maybe i will post all the intermediate photos of bench chaos later. at one point, both meters were completely torn apart and spread over the floor, so i could pick through the remains. after replacing missing parts, fixing some solder joints, and re-assembling, all the functions work, front and back connectors work and it detects that the VAC board is not installed. the display is also nice and bright. looks as good as my bench fluke. 

here it is, mostly re-assembled:



i found an option 09 board, too, which is on its way, and will bring the new meter completely up to grade.

still have to work through all the test and calibration procedures. glad i gave up on giving up on this one.   

edit: spent another thirty minutes at the bench comparing the new 8840A to the bench 8840A. from 10mV to 22V DC and from 10 to 10M ohms, it is within spitting distance. still, the self-tests indicate there's a problem in the DC section somewhere, so I will dig into that tomorrow.  but overall this looks like a win.

That's a score for sure buddy!

Nice 1