Test Equipment Anonymous (TEA) group therapy thread

[tggzzz]

What do you guys reckon you can expect when people use the word "mint" to describe the condition of a device? What does it denote in your book?

Good question. Since there are some many possible definitions, it can mean all sorts of things. Foe example: https://en.wikipedia.org/wiki/Mint_condition notes that the definition depends on the item!

However, mint coins have never been circulated and special precautions have been taken to ensure there are absolutely no blemishes.

[Specmaster]

Agreed, mint means no real signs of ever having been used so in other words, it has the appearance of just being taken out of the box for the first time.

[Mr. Scram]

I've always taken it to mean that the device looks like it's brand new or as the definition states "unmarred as if fresh from a mint". No dings, marks, scratches, blemishes or other marks of use can be seen and there's no yellowing or other signs of age. As bd139 says the device may have been used, but that should not be noticeable in any way.

I've noticed that some sellers seem to have definitions of what it means that can vary rather wildly, although we seem to be pretty much agreeing here.

[mnementh]

Voltnuttery with a 3.75 digit handheld? Not even close. Hell, that's neither sufficient to use a saturated Weston standard cell as a thermometer, nor to have to worry about draughts!

Start with 7 digits, and work upwards.

Well I thought that the 87V was a 4.5 digit meter? while not quite a 7 digit granted but there are different grades of voltnuttery and if you have 7 digits or more that i'm  certainly jealous, not that as I've said before, I need that level of accuracy, just love loads of digits  I doubt that real voltnutters dived straight in at a minimum of 7 digits but gradually worked their way upwards as I'm doing, started with 3.5 and in the space of 18 months upto 5.5, who knows what I'll have another 18 months, a empty bank account I reckon

Well, it might depend on why one is buying a 87V multimeter.   

It doesn't give you a high resolution because it has 3,5 digit in normal mode and 4,5 digits in high res mode.
What it does give you on that level is more accuracy than average handheld multimeters and therefore a higher level of confidence in what it displays.

If that is what one is buying it for, than it's likely that there's voltnuttery ahead..   

In my part -started right away with 6,5 digit benchtop multimeters made by Philips (PM2534/PM3535). Having realised that they had the resolution but not the accuracy I wanted I went further down that rabbit hole ending up with three HP 3456A. Bought a 87V as a side effect in that time..   

There are some LTZ1000 I bought over ebay from a guy in the USA that are still waiting to be checked and verified. And -if checked ok might pimp one of my 3456A.

Bid for a Prema 8017 7,5 digit bench multimeter yesterday but was outbid saved from going further down that rabbit hole.   

For my part, the interest in an 87x was did be to fill the void left when my first-run 87 was stolen during a move. I amended that desire to include one more digit, and thus zeroed in on the 189 as my target.

I am actually quite impressed with this meter; while it still only offers 2 DP in lowest resistance range, in Δ mode it can very repeatably tell the difference between 000, 1R0,  three or  four 1R0 in parallel, or one or two R200, to within .01-.02ohm. If I zero out with both probes jabbed in the the same solder fillet for each reading, it comes up dead on every time. Considering that it's a ruggedized meter intended for automation and process control, that is pretty effing amazing. Added to that the 1mS latching continuity tester that just does NOT miss, and it's an awesome useful piece of diag gear.

But here's something Fluke doesn't tell you in the manual: The junction test function has an open circuit voltage of 5.2V, current limited to exactly 1000uA. This higher open circuit voltage (most are right around 3.3v and varying current of ~1.5mA) makes it possible to turn on multiple LEDs in series and parallel (including high-wattage emitters that consist of 2 or 3 emitters in series or parallel), and it makes it useful as a handy current reference.

The only annoyance is that it only measures up to ~3.28V forward voltage (IRL); even though the scale says 5V, the specs say 3.1V full range.

mnem
Giggity.

[bd139]

I'm going to review it next to the BM867s and the U1241C so will see who gets beaten. It's going to be a tough match

Bored so browsing aliexpress. These look like a cheap bit of time nuttery fun .... https://www.aliexpress.com/item/Constant-temperature-crystal-OCXO-ENE3311B-ENE3311A-10MHZ-5V-square-wave/32829489181.html

[Mr. Scram]

The 87V is ideal for the regular poky proddy work. It's very quick and though there aren't many features, those features work well.

[Specmaster]

I'm going to review it next to the BM867s and the U1241C so will see who gets beaten. It's going to be a tough match

Bored so browsing aliexpress. These look like a cheap bit of time nuttery fun .... https://www.aliexpress.com/item/Constant-temperature-crystal-OCXO-ENE3311B-ENE3311A-10MHZ-5V-square-wave/32829489181.html

ditto I'm bored at the moment too. Yep that sounds like a interesting 3 way fight and any predictions on who gets beaten? My money is going on U1241C to be bottom of the pile, it might be a very close thing between the 87V and 867s, but I reckon the 867s will creep ahead. even with that slight bug you found, I reckon it will still pack the biggest punch of the three and even more so if the true retail prices are taken into account, you will get more "bang per buck" out of the 867s 

[Specmaster]

The 87V is ideal for the regular poky proddy work. It's very quick and though there aren't many features, those features work well.

The 867s is no slouch either and it scores double because it can do 2 items at once, i.e., Vac and also the frequency.

[med6753]

Brings back sad memories of losing in the final round of my 6th grade spelling bee on the word knaw gnaw.

Ah yes, the spelling bee, a peculiarly American way of torturing schoolkids. The British school equivalent is assuming that cross country running is a winter activity.

I loved cross country running in the winter! The enforced shower afterwards though; fuck that.

Running only occurred when there was an ankle deep puddle formed from melting slush. (Or where teachers might be lurking)

Teacher! Leave those kids alone! 

That's all I got. Going back to bed. Tired. Work was absolute lunacy last night. 

[Specmaster]

Another brick in the wall reference then, how many of us like Pink Floyd?

[med6753]

My favorite band.

BTW.....post 1000. I'm with the big boys now. 


Edit....now lemme go back to bed and be Comfortably Numb.

[Mr. Scram]

My favorite band.

BTW.....post 1000. I'm with the big boys now. 


Edit....now lemme go back to bed and be Comfortably Numb.

You're more of a 90s kid?

[med6753]

My favorite band.

BTW.....post 1000. I'm with the big boys now. 


Edit....now lemme go back to bed and be Comfortably Numb.

You're more of a 90s kid?

Hardly. Baby boomer here. Born in 1953. I'm an old fart.

[Specmaster]

My favorite band.

BTW.....post 1000. I'm with the big boys now. 


Edit....now lemme go back to bed and be Comfortably Numb.

You're more of a 90s kid?

Hardly. Baby boomer here. Born in 1953. I'm an old fart.

Ok then of you go its Time

[bd139]

One day closer to death ... 

Edit: purely by chance I realise I'm sitting here in a Wish You Were Here t shirt 

[mnementh]

Alternately, we could design a simple 4-wire PCB that plugs straight into the slot on the DE-5000; FUCK the wires entirely!

I'm up for something you can just ram in the front of it. HP did it with their high end LCR meters. Less wires and less contacts means less problems.

You think just the 4 wires, or shield as well on the back side?

I like that PCB fixture that plugs directly into the DE-5000 slots. I'm not sure if you need the shield. Any reason not to have it?

If you're measuring sub-20pF or sub-20uH or so values then stray inductance and capacitance is a major issue so you would need it then for sure. I'm not too sure about the implementation of the DE-5000 though; it purports to be a 4-wire measurement tool but the lead head is only 3 wire. There are two functions of 4-wire measurements here: elimination of common mode noise and acting as a guard against stray capacitance. Not sure how you can do both of those with 3 wire termination. I haven't looked deeply into it yet and not sure I can afford a proper 4-wire E4980A

                  


It actually IS true 4-wire AT THE PANEL. Each blade is 2-sided; giving 2 contacts for shield/guard, and 1 each for signal/sense on each probe. It is ONLY the termination at the end of the wires that makes it not true 4-wire; the alligators and tweezers are where the signal/sense are tied together. It actually is a pretty clever design; the blade contacts automatically short for calibration when there's no component plugged in.

This is why I was asking.

If we design a plugin breakout board, we can make it so it ONLY uses the 4 signal/sense wires, OR we can design it so the back of the thing is a solid fill connected to the GUARD/SHIELD.

Considerations are: Common mode noise created by that large fill, random stray inductance/capacitance created in reference to the signal/sense fills, and inductance introduced by the use of vias to bring the connections from one side of the board to the other.

If we design it with ONLY the 4-wire, we can design so that there is as little covalent area between the 4 pads as possible; we can make it so that they're all on the same plane with traces to the blades as far apart as possible, and as little overlap as possible between the two sides. This will be much more difficult if we have a GUARD/SHIELD on the back side.

Each approach has pros & cons; that's why I was asking your opinion. YOU know the way you'd want to use it.

Here's a quick sketch of what I was thinking for just a 4-wire board.

mnem
*Thinking too much*

[tggzzz]

One day closer to death ... 

Edit: purely by chance I realise I'm sitting here in a Wish You Were Here t shirt 

I am here. Where else could I possibly be?

[Specmaster]

The great gig in the sky?

[mnementh]

My favorite band.

BTW.....post 1000. I'm with the big boys now. 


Edit....now lemme go back to bed and be Comfortably Numb.

Yes, you too have proven that you have entirely too much free time on your hands.    Welcome to the club!   

One day closer to death ... 

Edit: purely by chance I realise I'm sitting here in a Wish You Were Here t shirt 

I am here. Where else could I possibly be?

Welcome to wherever you are.

mnem
"Tongue-tied and twisted, just an earth-bound misfit, I..."

[Specmaster]

Replacement knob for my TDS210 which has one missing from the trigger level control has been ordered, interestingly the https://www.3dhubs.com/3dprint site only lists basic colours but the centre in my city has some off white filament which looking at it, looks almost the same colour, certainly far closer than either light grey or white would have been anyway. It is supposed to be ready for me to collect in 2 working days, so Wednesday or Thursday I shall be seeing just good a match it really is. Being printed in PLA at 50 microns thickness for a even higher resolution all for a total £4.25, possibility cost less then the correct replacement (if they were available) from Tektronix.

[mnementh]

3DHubs has all kinds of service providers; many are local hackspaces, which is what it sounds like your center is, many are just hobbyists like me with a single printer on their back bench.  I don't know what their vetting process is; I haven't gotten to a point in my knowledge of 3DP where I'd be comfortable printing for profit.

But yeah, that's why I recommended you go to the service provider in person. Number one, you get to pick your color, and B) they get to see what they're promising to make so a lot likelier you are going to get what you want. 

mnem
Alternately, rutabagas.

[Johnny10]

Just finished cloning hard drive and cleaning up my 2nd Tektronix TDS7104 !!

Got this one missing hard drive.

Definitely a case of TEA, one is just never enough.

Still need buttons for front panel.

[med6753]

Today I was going to re-cap and install the power supply board for the RCA scope. Didn't happen. Normally when I get home from work in the AM I'm up until mid-day before going to bed. This morning I got home and fixed a meal. Then I did my weekly chores of sweeping, dusting, vacuuming (or as you Brits are fond of saying, “hoovering”) and then for some reason I crashed. Slept for several hours until waking up for few, took a piss, posted in here, then went back to sleep. That's highly unusual for me. So I'll do the supply tomorrow and show the results. Hopefully there will be an improvement of CRT trace quality and sharpness. Then onward to the vertical and horizontal boards.




…...thump, thump......thump, thump......There is no dark side of the moon. Matter of fact it's all dark......thump, thump......thump, thump.......thump, thump....... 

[bd139]

It actually IS true 4-wire AT THE PANEL. Each blade is 2-sided; giving 2 contacts for shield/guard, and 1 each for signal/sense on each probe. It is ONLY the termination at the end of the wires that makes it not true 4-wire; the alligators and tweezers are where the signal/sense are tied together. It actually is a pretty clever design; the blade contacts automatically short for calibration when there's no component plugged in.

This is why I was asking.

If we design a plugin breakout board, we can make it so it ONLY uses the 4 signal/sense wires, OR we can design it so the back of the thing is a solid fill connected to the GUARD/SHIELD.

Considerations are: Common mode noise created by that large fill, random stray inductance/capacitance created in reference to the signal/sense fills, and inductance introduced by the use of vias to bring the connections from one side of the board to the other.

If we design it with ONLY the 4-wire, we can design so that there is as little covalent area between the 4 pads as possible; we can make it so that they're all on the same plane with traces to the blades as far apart as possible, and as little overlap as possible between the two sides. This will be much more difficult if we have a GUARD/SHIELD on the back side.

Each approach has pros & cons; that's why I was asking your opinion. YOU know the way you'd want to use it.

Here's a quick sketch of what I was thinking for just a 4-wire board.

mnem
*Thinking too much*

That all makes sense now. Thanks for the time to explain it

TBH on that basis I'm happy with an out of the box fixture. The little crocodile clips are bi-wired and 4-wire so that's good enough. Rigid fixture is less important then. Probably fine above a couple of pF and a few tens of nH.

Added to the "to buy list". TBH I'd buy one now but I think I'd get shot.

[Specmaster]

It actually IS true 4-wire AT THE PANEL. Each blade is 2-sided; giving 2 contacts for shield/guard, and 1 each for signal/sense on each probe. It is ONLY the termination at the end of the wires that makes it not true 4-wire; the alligators and tweezers are where the signal/sense are tied together. It actually is a pretty clever design; the blade contacts automatically short for calibration when there's no component plugged in.

This is why I was asking.

If we design a plugin breakout board, we can make it so it ONLY uses the 4 signal/sense wires, OR we can design it so the back of the thing is a solid fill connected to the GUARD/SHIELD.

Considerations are: Common mode noise created by that large fill, random stray inductance/capacitance created in reference to the signal/sense fills, and inductance introduced by the use of vias to bring the connections from one side of the board to the other.

If we design it with ONLY the 4-wire, we can design so that there is as little covalent area between the 4 pads as possible; we can make it so that they're all on the same plane with traces to the blades as far apart as possible, and as little overlap as possible between the two sides. This will be much more difficult if we have a GUARD/SHIELD on the back side.

Each approach has pros & cons; that's why I was asking your opinion. YOU know the way you'd want to use it.

Here's a quick sketch of what I was thinking for just a 4-wire board.

mnem
*Thinking too much*

That all makes sense now. Thanks for the time to explain it

TBH on that basis I'm happy with an out of the box fixture. The little crocodile clips are bi-wired and 4-wire so that's good enough. Rigid fixture is less important then. Probably fine above a couple of pF and a few tens of nH.

Added to the "to buy list". TBH I'd buy one now but I think I'd get shot.

I'm still sitting on the fence, waiting for the actual test results against the Atlas and the Chinese tester. I'm not convinced that it's going to be better then the XJW01 other than it does have higher frequencies if you need them which to be honest you RF guys need more than I do..... but you never know.