Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 2259327 times)

Ingeniq, Sam Spastic, morris6, URI, neo and 38 Guests are viewing this topic.

Online tautech

  • Super Contributor
  • ***
  • Posts: 16713
  • Country: nz
  • Taupaki Technologies Ltd. NZ Siglent Distributor
    • Taupaki Technologies Ltd.
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32600 on: June 04, 2019, 10:10:49 pm »
A siglent scope out in the field, way to go!  :clap:



:)
Not a scope actually but the SVA1015X, a combo SA/VNA showing a 315 MHz center frequency Smith chart.
Used there to confirm the newly made and installed RF antenna still performed OK despite possible proximity effects from the tin roof on shed, nearby concrete pole and the poles galv steel wire back stay.
Search for my Antenna Project Log for the full story.  ;)

Much easier to lug to a remote location than some fine old   :phew:
Avid Rabid Hobbyist
 
The following users thanked this post: xrunner

Offline 0culus

  • Super Contributor
  • ***
  • Posts: 1808
  • Country: us
  • Electronics, RF, and TEA Hobbyist
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32601 on: June 04, 2019, 11:29:42 pm »
Pretty much like some students in my computer science program way back in one of the basic programming classes, who copied code from the internet for the lab final...and didn't even get the right programming language!!  :-DD (we were supposed to only use ANSI C)

That's poor attention to detail, isn't it?   :palm:
But there were similar "experts" in my EE class, too. The Prof. made a sarcastic joke one time after returning a test that next time* the cheaters should please try to hide their cheating attempts..   :-DD

*- to my and the satisfaction of the other non-cheaters "next time" meant the cheaters had to repeat and write another test..

Hahaha, perfect. I forget what happened to the students I was referring to. Given the strict academic honesty policy, they may or may not have gotten an F in the class depending on past incidents.
 

Offline Specmaster

  • Super Contributor
  • ***
  • Posts: 7835
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32602 on: June 04, 2019, 11:42:20 pm »
@Kosmic I'm not sure that it really is a cheap 34401A even for lucky fellows in North America time you've paid your shipping, given the state of it and the scant info by way of decent photos, it could still pose a significant risk of needing quite a bit of remedial work needing to done. When I think I only paid £133 for 2 x Solartron 7150 Plus meters, OK, they need the mains filter replacing which did add about £80 to the cost but even so they cost a lot less, but that said, I know I'm a cheapskate  :-DD :-DD :-DD

They sell at around 400 - 500$ here. So below 300$ is the lowest I seen for a while. Also the 34401a is a hell of a meter. Really like mine.

They seem like great DMMs - but I have a personal prejudice against the VFD in a lot of modern TE.  My experience with them (in a dozen or so pieces of audio/video gear in the house) is that they fade, and fade, and fade; my Sony receiver is almost impossible to read if the lights in the room are on, and the VCRs, DVDs and misc stuff is nearly as bad.  It's great if you love them, but I just can't.  I passed on a 34401 at a flea market a couple of weeks ago based on that, and the fact that $350 seemed a lot for something that was untested and appeared to have been rained on that morning.

It's worth a little less accuracy for me to have my Fluke/HP LED displays that I can read 20 feet away in full daylight.  They're also still easy to source replacements for.  Ultimately, it's what you're willing to accept and what suits your preferences.


This is so true, I currently have 2 Flukes, but I did for a while have 3, the first 8840A I acquired had a weak display and I flipped it when I acquired the other 2 because I was certain that their displays were in fine condition. I was working on the theory that as they were sold as parts only that I'd be able to make at least 1 good meter from the 3. The first was missing the AC option but both the other 2 came with that fitted and as they were working fine, flipped the 1st meter on Ebay. All of my other meters bar the 3466A have LCD displays, the HP ones are unlit and the Solartrons are edge lit and currently the only ones that are readable from a distance are the 2 unlit LCD's (3468A and 3478A). I think that the only one of those that would be fairly easy to obtain new displays for would the LED's for the 3466A as it is just a standard 7 segment and DP variety, all of the others have special custom displays.  :-DMM
« Last Edit: June 05, 2019, 12:09:24 am by Specmaster »
Who let Murphy in?
 

Offline mnementh

  • Super Contributor
  • ***
  • Posts: 5663
  • Country: ca
  • *Escaping The Suck*
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32603 on: June 04, 2019, 11:49:29 pm »
I recall bean warning to make the cross-section of the vane on that switch small enough not to give too much leverage so the switch didn't get broken; how did you resolve that?

Myself, I'd print a box to go over that board. If dirt and rust can get in there where it's mounted (as seen in the photo), bugs and moisture can too.

mnem
"You are in a maze of twisty little passages, all alike..."
The flow switch came with a selection of various length SS vanes and I trimmed one to the longest that would fit.
The arm it mounts on hit the side of the pipework and that provided a movement limit.

Timer lives in this green steel cabinet that while not entirely waterproof gives good enough protection against pump shed leaks and floods.....well it has thus far. A couple of times we've had a full tank of 15k litres from a 55m head dropped into the pump house with no ill effects on the electrics.  :phew:

So yeah I should put a little plastic condom hat over the timer PCB or at least give it a coat of PCB lacquer. Thanks.  :)

Yeah, that's all I was thinking... even if you just cover it with a duct tape prophylactic and drop the lid back on; SOMETHING to discourage Murphy's footsoldiers.  :-+ Hard learned lessons, "An ounce of prevention..." etc. ;)

mnem
"The devil, she never sleeps." ~ Old man Belmore >:D
 

Offline Specmaster

  • Super Contributor
  • ***
  • Posts: 7835
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32604 on: June 05, 2019, 12:06:25 am »
My day has gone to shit. Took my '04 Honda Civic in for annual inspection. Turns out the tires are dry rotted and cracked. Won't pass. I only drive that car a few thousand miles per year and the thread isn't even half worn. But they have a date code of 2013 and the rubber is drying out. Gonna take about $500 USD went all is said and done to bail it out of jail.  :palm:

Oh well.  :-//
A good buddy is real anal about his vehicles and every couple of weeks rubs some of that tire black on the sidewalls and never has issues with cracking.


I use a tire dressing on the sidewalls every time I wash the car.....which is often. I hate a dirty car. The cracking and dry rot was in the thread. There is nothing you can do about it.
Oh hell, that’s enough to make you go  :rant:
Yep, sure is but there's still yet another factor in tyre life and that is the dealer might have had them in stock a few years before you brought them.
Who let Murphy in?
 

Offline GregDunn

  • Frequent Contributor
  • **
  • Posts: 728
  • Country: us
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32605 on: June 05, 2019, 12:15:16 am »
This is so true, I currently have 2 Flukes, but I did for a while have 3, the first 8840A I acquired had a weak display and I flipped it when I acquired the other 2 because I was certain that their displays were in fine condition. I was working on the theory that as they were sold as parts only that I'd be able to make at least 1 good meter from the 3. The first was missing the AC option but both the other 2 came with that fitted and as they were working fine, flipped the 1st meter on Ebay. All of my other meters bar the 3466A have LCD displays, the HP ones are unlit and the Solartrons are edge lit and currently the only ones that are readable from a distance are the 2 unlit LCD's (3468A and 3478A). I think that the only one of those that would be fairly easy to obtain new displays for would the LED's for the 3466A as it is just a standard 7 segment and DP variety, all of the others have special custom displays.  :-DMM

That's what I love about my 8600A and 8800A meters - the displays are standard 7-segment LED units and they're still being made in one variety or another.  While I do love the 3478A display which announces "mVDC" or "OHMS" I can read the LED flags just as easily and I don't have to worry about having one die on me.
 

Offline VK5RC

  • Supporter
  • ****
  • Posts: 2339
  • Country: au
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32606 on: June 05, 2019, 12:25:08 am »
I am also a bit of fan of plain 7 segment LED provided they get the filter correct, fluorescent displays lose oomph, lcd - I have had quite a few go bad. With LED the only problem has been bad driver ICs. While the rap for OLED has not been good - my personal fav HH DMM (HP-A-K-U1253B) is because of the great contrast and viewing angles. Mine has been going well for about 5 years.
Whoah! Watch where that landed we might need it later.
 

Offline bitseeker

  • Super Contributor
  • ***
  • Posts: 8121
  • Country: us
  • Lots of engineer-tweakable parts inside!
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32607 on: June 05, 2019, 01:03:23 am »
Pretty much like some students in my computer science program way back in one of the basic programming classes, who copied code from the internet for the lab final...and didn't even get the right programming language!!  :-DD (we were supposed to only use ANSI C)

Talk about missing it by a mile! :-DD
I TEA.
 

Offline bitseeker

  • Super Contributor
  • ***
  • Posts: 8121
  • Country: us
  • Lots of engineer-tweakable parts inside!
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32608 on: June 05, 2019, 01:17:09 am »
@Kosmic I'm not sure that it really is a cheap 34401A even for lucky fellows in North America time you've paid your shipping, given the state of it and the scant info by way of decent photos, it could still pose a significant risk of needing quite a bit of remedial work needing to done.

They sell at around 400 - 500$ here. So below 300$ is the lowest I seen for a while. Also the 34401a is a hell of a meter. Really like mine.

Yeah, the prices have been going up since I bought mine several years ago. I paid even less for my 34410A than for my 34401A. Bizarre.

My only concern about that vintage of 34401A is the unobtanium display controller/VFD driver. But, then again, this is TEA, so just buy an extra. ;D
I TEA.
 

Offline GregDunn

  • Frequent Contributor
  • **
  • Posts: 728
  • Country: us
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32609 on: June 05, 2019, 01:52:06 am »
I am also a bit of fan of plain 7 segment LED provided they get the filter correct, fluorescent displays lose oomph, lcd - I have had quite a few go bad. With LED the only problem has been bad driver ICs. While the rap for OLED has not been good - my personal fav HH DMM (HP-A-K-U1253B) is because of the great contrast and viewing angles. Mine has been going well for about 5 years.

Yes, my HP3490 had a bad chip in the display circuit causing extra DPs and segments to light up - just a flaky 7404.  Happily, no other LED display issues except a couple of Flukes with dying PSU caps which caused the display to dim and flicker.  I have an old Fluke 8020A whose LCD died, but was able to hack one of the modern displays in to replace it.  So far I haven't had to retire a meter due to a broken display.
 

Offline worsthorse

  • Frequent Contributor
  • **
  • Posts: 881
  • Country: us
  • aina varma, usein väärin
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32610 on: June 05, 2019, 02:36:46 am »

I'm considering a TDR myself now. I spent half the evening trying to work out which bit of coax is the good one. That would have an answer to me pretty quickly as one of them has a broken middle somewhere :(

Here's a quick-and-dirty DIY setup:

https://www.allaboutcircuits.com/projects/build-your-own-time-domain-reflectometer/

I think W2AEW did a video on a signal generator and oscilloscope. The first "TDR" I built used a pretty simple pulse generator circuit, an oscilloscope, and pen/paper.
specialization is for insects.
 

Offline bitseeker

  • Super Contributor
  • ***
  • Posts: 8121
  • Country: us
  • Lots of engineer-tweakable parts inside!
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32611 on: June 05, 2019, 03:23:03 am »


I TEA.
 
The following users thanked this post: URI

Offline 0culus

  • Super Contributor
  • ***
  • Posts: 1808
  • Country: us
  • Electronics, RF, and TEA Hobbyist
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32612 on: June 05, 2019, 03:53:45 am »
Man, I looked at the prices for the new Tek 3 and 4 series once you start adding options...  :o

Suffice to say, if I buy a new digital 'scope rather than something a bit older and used, I may be looking hard at that promotion that R&S is running this year.
 

Offline tggzzz

  • Super Contributor
  • ***
  • Posts: 10463
  • Country: gb
    • Having fun doing more, with less
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32613 on: June 05, 2019, 04:15:51 am »
As I said, with TDR if all you want to do is see open/short and lengths of a few yards, you can get away with murder - as shown in those videos.

But the key features of a TDR are bandwidth (i.e. step risetime and scope input) and good signal integrity. In those respects those two videos show suboptimum results, especially the risetime and signal integrity of the step generator.

With care and a little effort, even a homebrew board and jellybean components can generate a much better step, e.g.



But even then, little beats the pretty and seductive twinkle of an old analogue diode sampler and CRT :) Ought to try to make a video sometime; that ought to be better than a static photo.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline salvagedcircuitry

  • Regular Contributor
  • *
  • Posts: 81
  • Country: us
  • Electrical Engineer | Hobbyist | Camera Enthusiast
    • salvagedcircuitry
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32614 on: June 05, 2019, 06:02:26 am »
New score for the lab :D
Good ol thurbly!
will need some repair love, but well worth it  8)





SalvagedCircuitry
www.salvagedcircuitry.com
 
The following users thanked this post: bd139

Offline bitseeker

  • Super Contributor
  • ***
  • Posts: 8121
  • Country: us
  • Lots of engineer-tweakable parts inside!
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32615 on: June 05, 2019, 06:11:05 am »
Nice one. Hopefully, it isn't anything too hairy to get up and running again.

It always makes me laugh the way eBay continues to lie about how much something sold for when an offer is accepted. Anything to make people believe they should list or bid higher on the next one.
I TEA.
 
The following users thanked this post: salvagedcircuitry

Offline salvagedcircuitry

  • Regular Contributor
  • *
  • Posts: 81
  • Country: us
  • Electrical Engineer | Hobbyist | Camera Enthusiast
    • salvagedcircuitry
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32616 on: June 05, 2019, 06:18:24 am »
Yeah. I think the repair should be ok. the unit is not too old so parts should still be attainable. I may be taking a break from higher priced items on ebay though, now that it has become tax-a-chusetts:
https://www.ebay.com/help/buying/paying-items/paying-tax-ebay-purchases?id=4771&amp
https://esellercafe.com/on-july-1-ebay-will-collect-sales-tax-for-four-more-states/

The dog days are over, that's for sure.  :-\
I'm glad I snagged my higher end test gear when i did....
SalvagedCircuitry
www.salvagedcircuitry.com
 

Offline bd139

  • Super Contributor
  • ***
  • Posts: 12551
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32617 on: June 05, 2019, 07:20:03 am »
I'm considering a TDR myself now. I spent half the evening trying to work out which bit of coax is the good one. That would have an answer to me pretty quickly as one of them has a broken middle somewhere :(

If you are only interested in clean breaks in the middle of a long cable, you can probably get away with a homebrew sharp-edged step generator and scope. Or possibly a noise generator, SDR and inverse FFT.

If you want to find more subtle problems near connectors, then you need a Tek 1502 :) plus they are fun to use at a hamfest to find a cable's actual impedance, cf nominal impedance.

Yeah I’ve got a Jim Williams pulse generator I built somewhere and a 74LVC14 one. Need to find them though first. I think I stole the boost converter for something else as well.

As always, as this is the TEA thread, it’s also an excuse to buy another shiny box of goodness to play with.


I'm considering a TDR myself now. I spent half the evening trying to work out which bit of coax is the good one. That would have an answer to me pretty quickly as one of them has a broken middle somewhere :(

Here's a quick-and-dirty DIY setup:

https://www.allaboutcircuits.com/projects/build-your-own-time-domain-reflectometer/

I think W2AEW did a video on a signal generator and oscilloscope. The first "TDR" I built used a pretty simple pulse generator circuit, an oscilloscope, and pen/paper.

Thanks for this. I’ve seen the w2aew video and actually built a couple of pulse generators. This is merely an excuse to obtain another toy to play with  :-DD
 

Offline bd139

  • Super Contributor
  • ***
  • Posts: 12551
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32618 on: June 05, 2019, 07:22:38 am »
New score for the lab :D
Good ol thurbly!
will need some repair love, but well worth it  8)



I nearly fell off my chair until I saw the $42 offer accepted  :-DD

That’ll work again. I’ve only ever had to scrap one Thurlby item ever and that was because the batteries had eaten it completely. Everything else has come up perfect. I have three of their supplies, albeit older PL ones, and use them more than the HP ones. They are excellent.
 
The following users thanked this post: salvagedcircuitry

Offline bd139

  • Super Contributor
  • ***
  • Posts: 12551
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32619 on: June 05, 2019, 07:25:01 am »
As I said, with TDR if all you want to do is see open/short and lengths of a few yards, you can get away with murder - as shown in those videos.

But the key features of a TDR are bandwidth (i.e. step risetime and scope input) and good signal integrity. In those respects those two videos show suboptimum results, especially the risetime and signal integrity of the step generator.

With care and a little effort, even a homebrew board and jellybean components can generate a much better step, e.g.



But even then, little beats the pretty and seductive twinkle of an old analogue diode sampler and CRT :) Ought to try to make a video sometime; that ought to be better than a static photo.

I did actually consider that 7623 with sampling head on eBay a few days ago for this very reason  :-DD

Then I unconsidered it in the effort to tidy this place up.
 

Offline tggzzz

  • Super Contributor
  • ***
  • Posts: 10463
  • Country: gb
    • Having fun doing more, with less
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32620 on: June 05, 2019, 07:37:32 am »
The latest acquisition is slightly strange... Three of us have chipped in to buy a scanning tunnelling microscope, a.k.a. an atomic force microscope. Hopefully the main challenge will be working out what the interface to the computer is. At least there will be three sets of eyes on the problem.

So the next task is to to make the unpleasant long journey to a hell-hole of a holiday resort, and hopefully retrieve my leopard on the way back.

And news just in...

Since I didn't win my third luggable spectrum analyser, the auction house intermediary thoughtfully suggested things to assuage my sorrow: some "palisade gates" and "Starbay Shagreen and Acacia Walnut 2 door 3 drawer cabinet functional with boundless character". Thank god I haven't got enough money in the bank, otherwise I would have been sorely tempted. Not.
« Last Edit: June 05, 2019, 07:45:37 am by tggzzz »
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline Brumby

  • Supporter
  • ****
  • Posts: 9480
  • Country: au
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32621 on: June 05, 2019, 07:47:54 am »
Since I didn't win my third luggable spectrum analyser, the auction house intermediary thoughtfully suggested things to assuage my sorrow: some "palisade gates" and "Starbay Shagreen and Acacia Walnut 2 door 3 drawer cabinet functional with boundless character". Thank god I haven't got enough money in the bank, otherwise I would have been sorely tempted. Not.

Don't you just love that?!!

I get some of my best laughs when that sort of thing happens.
 

Offline med6753

  • Super Contributor
  • ***
  • Posts: 4742
  • Country: us
  • Tek nut
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32622 on: June 05, 2019, 07:48:52 am »
Yeah. I think the repair should be ok. the unit is not too old so parts should still be attainable. I may be taking a break from higher priced items on ebay though, now that it has become tax-a-chusetts:
https://www.ebay.com/help/buying/paying-items/paying-tax-ebay-purchases?id=4771&amp
https://esellercafe.com/on-july-1-ebay-will-collect-sales-tax-for-four-more-states/

The dog days are over, that's for sure.  :-\
I'm glad I snagged my higher end test gear when i did....

I'm very surprised that New York State isn't on that list. In fact I would have expected NY to be the first to demand that Ebay collect sales tax. They don't call NY "Land of Taxes" for nothing and I'm sure sooner or later they will be added.  :--
An old gray beard with an attitude.
 

Offline bd139

  • Super Contributor
  • ***
  • Posts: 12551
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32623 on: June 05, 2019, 08:31:26 am »
The latest acquisition is slightly strange... Three of us have chipped in to buy a scanning tunnelling microscope, a.k.a. an atomic force microscope. Hopefully the main challenge will be working out what the interface to the computer is. At least there will be three sets of eyes on the problem.

So the next task is to to make the unpleasant long journey to a hell-hole of a holiday resort, and hopefully retrieve my leopard on the way back.

And news just in...

Since I didn't win my third luggable spectrum analyser, the auction house intermediary thoughtfully suggested things to assuage my sorrow: some "palisade gates" and "Starbay Shagreen and Acacia Walnut 2 door 3 drawer cabinet functional with boundless character". Thank god I haven't got enough money in the bank, otherwise I would have been sorely tempted. Not.

Having just had a report of one of the aforementioned holiday resorts, get tooled up  :-DD

I have seen a couple of electron microscopes on ebay but never an STM. Didn't think they were in the remotely affordable territory on the second hand market yet.  I've seen a couple of attempts to build them though at home. From my bookmarks... http://www.angelfire.com/electronic2/spm/index.html . Either way, enjoy that as it will be a blast playing with it. I got to spend half a day as a muggle at Glaxo once in the distant past watching them play with one and an NMR machine used to test my illicit home brew drugs.

If the leopard is convincingly well stuffed it should live on the passenger seat. Then you can pretend you're a Saudi Prince  :-DD
« Last Edit: June 05, 2019, 08:35:43 am by bd139 »
 

Offline Specmaster

  • Super Contributor
  • ***
  • Posts: 7835
  • Country: gb
Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #32624 on: June 05, 2019, 08:39:28 am »
Just been advised that my latest purchase, the Hacker Herald RP37A for restoration is going to be delivered within the next hour. I finally get to see just how much of a challenge its going to be.  :clap:
Who let Murphy in?
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf