Test Equipment Anonymous (TEA) group therapy thread

[bitseeker]

Here's a TEA question.   Have any of you had a piece of test equipment stop working, so you think "If I had a manual maybe it would have some servicing information and I could fix this thing."  So you get on the computer and fire up your favorite search engine, and after some searching consider yourself lucky to have found a PDF of the manual online.  So you save the PDF and look at it a bit and figure that's good enough for today.  Later I'll dig into it and fix the piece of test equipment.

The next day you go back to the lab and see that you had a manual all along.  A real physical copy, sitting on the shelf a few feet from the piece of test equipment, and only a couple feet from where you were sitting while searching for the manual online...

I haven't had the pleasure of such fortune. Congrats on finding your manual. I don't have many originals. They are cool, though.

[Berni]

Here's a TEA question.   Have any of you had a piece of test equipment stop working, so you think "If I had a manual maybe it would have some servicing information and I could fix this thing."  So you get on the computer and fire up your favorite search engine, and after some searching consider yourself lucky to have found a PDF of the manual online.  So you save the PDF and look at it a bit and figure that's good enough for today.  Later I'll dig into it and fix the piece of test equipment.

The next day you go back to the lab and see that you had a manual all along.  A real physical copy, sitting on the shelf a few feet from the piece of test equipment, and only a couple feet from where you were sitting while searching for the manual online...

Not so much since i don't have much in the way of paper manuals. A few that i have are actually ones that can't be found on the internet.

Test gear has been shipping without real paper manuals for a long time now so it will soon be a thing of the past to own real dead treee manuals for gear. They rather give you a CD with the manual or just simply expect you to go download it from there website. People like Keysight are really good at keeping the old manuals available on there website, some other manufacturers not so much.

[URI]

Here's a TEA question.   Have any of you had a piece of test equipment stop working, so you think "If I had a manual maybe it would have some servicing information and I could fix this thing."  So you get on the computer and fire up your favorite search engine, and after some searching consider yourself lucky to have found a PDF of the manual online.  So you save the PDF and look at it a bit and figure that's good enough for today.  Later I'll dig into it and fix the piece of test equipment.

The next day you go back to the lab and see that you had a manual all along.  A real physical copy, sitting on the shelf a few feet from the piece of test equipment, and only a couple feet from where you were sitting while searching for the manual online...

Well, I'm a bit ashamed, but as we are all TEAs here I'll disclose one of my secrets..

This happened to me.
Yes.
But a little bit different

Once I got a manual with a TED (Test Equipment Device), put it aside on my bench and played with the new toy.
A stack of other paper grew on it.

I eventually forgot about it.

Then, one day, I wanted to use the instrument and had some issues with it, so I needed a manual.
I searched on the net (it was quiet rare) for a paper copy because of the schematics and felt lucky to find an original (no copy) I could buy from a guy in Germany.   
The manual arrived, I fixed the issues and put it on the shelf aside my other paper manuals.

Month later..  I rebuilt my bench and before that I had to tidy it up.

To my surprise at the bottom of a paper stack there was a manual that I clearly remembered I had put on the shelf month before, how could it get here on my bench again...?      

[med6753]

Tea has to be one of the best threads if not the best thread on this forum, now that we are officially 600 pages long, how does that stack against other threads? Surely there can't be another with such a meteoric rise as this one?

You can find some forum stats and top-lists at https://www.eevblog.com/forum/stats/

• This thread has been #1 in replies for a while now. Amazing level of engagement!
• By views, we're not in the top-10 yet. Current count is approximately 614K. But it's a young thread. #9 and #10 are from 2010 and 2013, respectively. TEA started last year.

Bitseeker, did you ever in your wildest dreams think that it would take of like the sky rocket it is? You have created a true monster here 

There's no way I could have known that reception would be as good as it has been. Of course, the concept was born a bit tongue-in-cheek. Little did I know it would resonate with so many, partly because of the light-hearted humor, but also because there's a bit of truth to it that folks can identify with.

Really, it's all thanks to you, the poor similarly infected souls who keep coming back for more. Also, thanks to Dave for building the overall community. Without it, it's unlikely we'd all run into one another.

I've had some successes building online communities over the years, including one that was infiltrated twice by people who either wanted to take over or sabotage what we built. You just never know what will happen.

TEA, on the other hand, just exploded. Pretty amazing.

Edit, just checked and I've been here for 517 pages and so far it's been nothing short of a hoot and pure delight, what a great of bunch girls and guys we have here. I'm proud to say that I'm a part of this wonderful group and culture we have and my TEA is not showing any signs of being cured even though I'm having a bit of a cull, just getting ready for even more items in need of some TLC and given a new lease of life.

I guess that makes you certifiable — a long term case. Glad you found a room in the TEA house that you like and a bench that fits.

And don't worry about the intermittent culling behavior. It will pass. (More accurately, it creates a void that TEA will fill.)

Thanks to you I've just about spent all my retirement. 

But I wouldn't trade it for anything! Spent it!!   

[bitseeker]

Retirement's supposed to be fun. You win, med!

[med6753]

Retirement's supposed to be fun. You win, med!

You are so right. But my friends think I'm a little strange. My family thinks I've completely lost it. And my girlfriend just shakes her head. But I can come in here everyday and talk geek and you folks get it!  So refreshing.

And of course we have to thank our benefactor, Mr David Jones, so allowing us loons to talk and trade stories of our addiction. I don't know what I'd do if the blog suddenly wasn't there. 

BTW.....I don't think Dave has ever posted in this thread. I understand he can't possibly keep up with all the activities of the blog but I'm sure he must have noticed how big the TEA thread is. 

[bd139]

Some TEA porn from w2aew...

https://youtu.be/c-y8UmoHbtw

[med6753]

Let's see if we can figure out what's wrong with the P6430 Temperature Probe that came with the 465B/DM44 purchased last week.

The manual and the probe. The probe body unscrews and the sensor assembly head is an NPN transistor encased in plastic. I found out that it's roughly equivalent to a 2N2484. So let's test the sensor head.


The test set up.


The results. It's FUBAR.  It's showing as a diode. Mouser has the 2N2484 in stock and I may order it. As far as getting the original Tek part? Yea.....right. In your dreams. 

[bd139]

Any NPN Si transistor will probably do the job to be honest. Would need recalibration for the specific sensor but it's mostly consistent across transistor types.

It's probably showing as a diode as the base/collector is shorted in this arrangement. These work on the basis that Vbe is proportional to temperature if Ic is constant.

quick LTspice simulation with 10 degree increments as an example. Vout is the voltage at the collector relative to ground:



2n3904 used because it was already in LTspice!

Edit: Ebers-Moll theoretical model used here.

[bd139]

Just did some research into this (because I'm bored) and it's slightly more complicated. It is a 3 terminal probe. The collector current is switched between two levels at around 2KHz and the difference in the Vbe is used as the readout. This results in a gain of 10mV/div. Neat-o.

Accuracy isn't that great. if probe and DM44 are calibrated together, then +/-2oC. Else +/- 8oC.

I'd just throw a 2n3904 in there and see what happens. It'll need calibration either way if you want it within a couple of degrees.

[Cerebus]

A tad clearer if plotted like this:

[bd139]

Very true 

(I'm not a regular LTspice user. Usually use pencil and paper )

[med6753]

As near as I can tell from the manual the sensor contains a discrete transistor. It does indeed have three terminals. The emitter and collector are wired to the connector and the base connects to the shell. I made sure it was wired correctly. The test of the sensor was all 3 terminals and the result was a "diode" so apparently it's no good.

You're probably right about a 2N3904 working just as well after you calibrate it.

[factory]

I think we need a test gear chiropodist. The most common problem I find with test gear is foot problems

Sheesh, the subject of feet came up only a couple of weeks back and I dropped a link to a thread then and mnem gave us more from thingyverse...or whatever.

This guy posted that he does a lot of the Tek ones and I asked him when he joined if he'd do HP and others. Yeah he will.
Here's his site:
https://www.n0dy.com/

I think there may already be a supply of suitable feet (& tilt stands) for the full size HP cases out there, it's finding where they get them from that is the problem. Have a look at the Rod-L Electronics webpage and on ebay, do the cases look familiar?

http://www.rodl.com/

The company was started by Roy Clay who had previously worked as the software development manager on the HP 2116A computer.

http://www.rodl.com/management.html

There are a couple of manuals on the web but no mention of any part numbers for the feet. So maybe something else to look out for donor feet if they are cheap, but then again the TEA could kick in & you may end up with a pile of them. 

I'd never heard of Rod-L Electronics before I found an ebay listing where someone had mentioned the HP looks in the description. Clare stuff seems to be the go-to brand where I work for high voltage insulation testers (now part of Seaward).

David

edit, found a picture of one showing the feet.

[Cerebus]

As near as I can tell from the manual the sensor contains a discrete transistor. It does indeed have three terminals. The emitter and collector are wired to the connector and the base connects to the shell. I made sure it was wired correctly. The test of the sensor was all 3 terminals and the result was a "diode" so apparently it's no good.

You're probably right about a 2N3904 working just as well after you calibrate it.

Because it uses the difference in V_BE at two different collector currents it is highly insensitive to the transistor type. Just for tits and pickles, here's the difference in V_BE at two collector currents plotted against temperature for two very different NPN transistors, the humble 2N3904 and the beastly 17 amp 2SC5200:




Note that the curves for the two different transistors essentially plot as one in the upper trace.

[bd139]

All hail physics!

I really love bipolar transistors. There I admitted it. I should have married one.

Edit: To note, this is the reason that they do the differential measurement. When you have a Y=MX+C linear transformation, the X is constant so the only calibration parameter is C.

[med6753]

If you're married to a woman you've got the bipolar part already covered


I never said that and if questioned I will deny it to my dying breath. 

[Specmaster]

If you're married to a woman you've got the bipolar part already covered


I never said that and if questioned I will deny it to my dying breath. 

Sadly you put it in writing as well [emoji16]

[neo]

Some extra SPECIAL TEA GOODNESS for you all today! Fluke 8200A, tested, guaranteed and warranted for two full years from date of purchase! I bought this meter on ebay and then i dreaded the possibilities, too good to be true, but no it is true! 150 for a working nixie meter that even comes complete with all the options and no stickers barring entry into the device. It came in a radwell international box, obviously since thats the company, double sealed in plastic and then padded, with that expanding foam stuff that conforms to the box, I even got a bag of mints and a power cord. I'd have pictures here but my camera crapped out, maybe later when its warmed up and i have the accuracy results. Whats so good and special you may ask? THEY HAVE MORE https://www.radwell.com/en-US/Buy/FLUKE/FLUKE/8200A , nixie fans rejoice!

Also back to other topics, my table or more specifically it's posts. My dryer crapped out so i had to return it to homeowner hell anyways, while there i checked their inventory of beams, lo and behold! Brand new fresh off the truck just untied 4x6 beams! Straight as an arrow because they didn't even have time to abuse them yet! Sadly since my dryer crapped out again hamfests are going to be a little tight...

Speaking of hamfest, this friday and saturday i'm going to one, should be fun to see what i drag home. I have a rather fat wad still unaffected by the dryer.

[med6753]

Stringing a clothes line in the back yard will solve your dryer problem. And then your neighbors will take pictures of your knickers like Specmaster does with his. 

[bd139]

 

[tautech]

Nickermaster and penis fingers.........sounds like a sick bunch of characters.....who else ? 

[Specmaster]

Nickermaster and penis fingers.........sounds like a sick bunch of characters.....who else ? 

Don't get us started, it could turn ugly [emoji6]

[neo]

Stringing a clothes line in the back yard will solve your dryer problem. And then your neighbors will take pictures of your knickers like Specmaster does with his. 

Good idea except for the fact i already bought a new dryer to please the powers that be. 

[Berni]

Some TEA porn from w2aew...

https://youtu.be/c-y8UmoHbtw

That thing sure beats out my HP one when it comes to the amount of boatanchory, looks like it might be getting towards the two person lift category.