Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 14548721 times)

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Online tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88325 on: April 16, 2021, 03:00:42 pm »
In the early '50s, I was given Phenobarb, which may have worked, but gave me heart palpitations.

I think you've misremembered. That would have been ephedrine and phenobarbitol in combination. Ephedrine to treat the asthma, phenobarbitol to counter the methamphetamine like effects of the ephedrine, but only on the behavioural side of things and then only poorly; you still get all the somatic bad side effects of the ephedrine (high blood pressure, palpitations, sweating, insomnia, trembling and many more). I too was fed that evil combination in my youth.

The modern replacement for ephedrine, given when other things aren't working, is aminophylline (theophylline) and they hook you up to a cardiac monitor while they are giving you the loading dose and for a day or so until they are sure they have got the dose right. The therapeutic index (the difference between and effective dose and a dangerous dose: LD50/ED50) of aminophyline is about 3, one of the lowest of any drug in use (For cocaine it's 15, for morphine 70). i.e. Take three pills instead of the one you're supposed to and it'll probably kill you. That this has replaced ephedrine tells you all you need to know about the safety of ephedrine.

Not quite LD50, but paracetamol max allowed has been reduced to 65mg/kg/day. That's uncomfortably low for my (small) daughter.

IIRC if you exceed one (very safe) metabolic pathway removing the paracetamol, a different one becomes active and deposits formaldehyde in the liver. Oops.
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Offline Kosmic

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88326 on: April 16, 2021, 03:13:32 pm »

I suspect what he meant was a LCR/ESR meter; as in a single device which combines the two functions. These are common nowadays, they weren't always.

When ESR meters as commonly used in electronics repair were first devised, they showed two parameters: Capacitance and ESR. They worked on capacitors, period.

Some LCR Meters, particularly older laboratory units, use a substitution bridge to determine the value of the DUT and don't actually offer ESR or Tan δ parameters.

It is only later models which can use the magic of cheap microprocessors and multiple ADCs which can offer all the above in a single device, even giving all these parameters in one test.

Or is that not the question you were asking...?

mnem
 :popcorn:

It would be really surprising to find a LCR meter that is not able to measure Rs. Even if they have different name, ESR is equal to Rs. All LCR meters can measure Rs. Even the old one.

Personally, I think ESR meters are useless when you have a good LCR meter. Maybe ESR meters have better range ?

I'm not sure why people tend to believe ESR meters actually measure something that LCR meters can't. The LCR meter is the superior instrument, ESR meter only measure a subset (Rs and if you are lucky Cs) of what a LCR meter can do.

I think it's the test parameters, and the inconvenience. ESR meters typically operate at one of several... well, I can't even call it a standard, as there really is no such thing... lets call it "commonly used" frequencies dependent upon capacitance range, such that results from one design of ESR meter are comparable to another.

Calculating it from Rs means knowing what frequency the LCR meter is running at right now, with this DUT, and it means that while you're diag-ing a PCB, every time you have to stop probing, pick up a pencil, and do some math to determine whether the cap is healthy or not.

What do you want to calculate here ? ESR == Rs. ESR is also dependent on frequency.

ESR as it is used on a repair bench boils all that down to a simpler, more repeatable result of ESR vs Capacitance which you can just eyeball, gauge whether it's reasonable, and move on to the next suspect component. Having used the DE-5000 for a couple years now, and being able to compare results from both test functions, I find that the Tan δ function is much more reliable as far as giving a definitive Yes/No answer, simply because if you aren't sure based on the internal "chart" one develops when using any such device, you can usually find this parameter in a MFR's datasheet.

I'm not questioning the use of ESR (Rs) here. And as you said, Tan δ (or D for Dissipation Factor) is most of the time more revealing.

The entire table of "acceptable ESR values" that people refer to is based on a chart created by Dick Smith decades ago, which unfortunately didn't include a LOT of today's Low and Ultra-Low ESR capacitor product lines. So what has evolved since is kindof a mishmash of both. That in and of itself is the main reason ESR as measured by an ESR meter is pretty useless from an enginerding standpoint.

That is also, I think, part of the reason Robert and I butted heads on this so hard (and keep doing so)... he's a hardcore engineer who has kept up with his professional development, so has a lot invested in knowing what he's doing, while I'm a retired engineer who was (a) never really that good at any of it except keeping several hundred circuits from a design in my head and (2) had to fall back on service & repair for my livelihood because I couldn't hack the modern corporate crazy-factory that is commercial/industrial engineering.  :-//

Sure ESR has been used in the industry for a long time and most components are not specified for  Tan δ (Dissipation Factor). Not sure why this is a justification for measuring ESR with a ESR meters when a LCR meter can do the same measurement  :-//

I'm just saying you don't need both. If you are only interested in ESR, get a ESR meter. They are normally cheaper than full blown LCR meter. If you want more measurements (Cp, D, I, etc ..), you probably want a LCR meter.

But I'm forgetting where i'm posting right now. A normal person should have at least 4 LCR meters and 4 ESR meters, just to be sure.  ;D
« Last Edit: April 16, 2021, 03:38:58 pm by Kosmic »
 
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Offline Saskia

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88327 on: April 16, 2021, 03:31:14 pm »
ok, nasty funngames ...

another RTX2070 blew up. Will crash after a couple of minutes, artifacts on the screen, after reboot it falls back to VGA.
Well, Zotac has 5 years warranty, does it not ...
Called Zotac: hey, my graphics card is misbehaving
ok, it is still under vendor warranty, contact mindfactory.
but they will only give me a refund, and I want the card repaired or swapped out ?
Well, their choice.
But I do have this extended warranty ?
Yes, but only after the normal warranty expires. We cannot accept the card right now.
but, if I RMA it via mindfactory, I don't get the card back, I'd rather have a working card instead of the purchase price in 2019 ...
Prices have tripled since then ...
weeeeeellll, you could put the card aside and wait for the vendor warranty to expire and then make use of the extended warranty. Once the vendor warranty is over, your extended warranty kicks in and we can exchange the card ...  |O |O |O |O
You are welcome to open an RMA case in January next year and we will happily swap out the card. So sorry, there is nothing we can do, our chinese bosses dictate us how to go ahead. Many apologies, but we can confirm your card is under warranty until December 2024.

D'oh.
The card is now on the to be returned stack ... FFS ... argl ...
which means: do not break a Zotac card while it is under vendor warranty and make sure you register it for extended warranty, because that's the only way you can get it replaced.

« Last Edit: April 16, 2021, 03:40:48 pm by Saskia »
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88328 on: April 16, 2021, 03:34:43 pm »
Liking my shitty Intel GFX suddenly  :-DD
 

Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88329 on: April 16, 2021, 03:40:57 pm »
I mentioned previously that I noticed that nuvistors need a lot of burn-in time to become stable. So I wanted to conduct a quick experiment with the 2 supposedly tested 7586 nuvistors I received last week. I don't know how they were tested or how long ago. And I suspect if they were tested it was nothing more than a quick emission test. So let's see what happens when plugged in the Type 321A.

Baseline measurement: The current 7586 installed as it warms up comes from off screen at the bottom and after about 5 or 10 minutes settles and stabilizes on center line.

Spare nuvistor number 1:  After 10 minutes was still off screen at the bottom. Had to adjust vertical position off center to get it on screen. And could not adjust it off screen at the top. But square wave trace looked good. So in order the center this for equal deflection would require fiddling with the DC balance and possibly the gain.


Spare nuvistor number 2:  Warmed up and trace went from bottom all the way off screen at the top. Could not get it on screen with the vertical position. This nuvistor has a large DC offset and in fact may be defective. I think it would take considerable fiddling with the DC balance to get it on screen.     


So, quick conclusion. These nuvistors are flaky as hell and anytime one is replaced considerable adjustment is going to be required. I'm glad FET's replaced them. 


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Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88330 on: April 16, 2021, 04:01:23 pm »
FETs aren't any better to be honest. Possibly even worse.

Fine example is the good old Radio Shack supplied MPF102 which makes its way into a bunch of ham projects. The Idss is specified at between 2mA and 20mA. Basically whatever FET came off the line gets that labelled on it. The result of this is lots of projects which don't work well and angry hams. The authors never explain that they actually had to buy a few and sub them before one actually worked in circuit well enough, because that doesn't sell magazines and books.

If you want a better range then you have to use the 2N5484/5/6 which is still specified at between 1-5, 4-10, 8-20mA respectively.

This is why you see "HP selected" and "Tek selected" FETs a lot in their early designs which are even tighter specified. They buy 10,000 better specified ones and then grade them separately and give them a vendor specific number. Still at the end of the day it's same silicon as a shitty MPF102 from Rat shack.

The HP427A is even nastier because to offset the gate leakage on the impedance converter FET they have a diode which is matched with it and temperature. Fortunately they don't ever seem to go wonky  :scared:

On the nuvistors I'd leave them in there for a couple of hours then check the voltage at the cathode and see if it has settled or not. Then frig the DC bal until it's fine. Tek used to cook their tubes for ages in racks before installing them in kit.
« Last Edit: April 16, 2021, 04:08:22 pm by bd139 »
 
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Offline SilverSolder

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88331 on: April 16, 2021, 04:04:01 pm »
ok, nasty funngames ...

another RTX2070 blew up. Will crash after a couple of minutes, artifacts on the screen, after reboot it falls back to VGA.
Well, Zotac has 5 years warranty, does it not ...
Called Zotac: hey, my graphics card is misbehaving
ok, it is still under vendor warranty, contact mindfactory.
but they will only give me a refund, and I want the card repaired or swapped out ?
Well, their choice.
But I do have this extended warranty ?
Yes, but only after the normal warranty expires. We cannot accept the card right now.
but, if I RMA it via mindfactory, I don't get the card back, I'd rather have a working card instead of the purchase price in 2019 ...
Prices have tripled since then ...
weeeeeellll, you could put the card aside and wait for the vendor warranty to expire and then make use of the extended warranty. Once the vendor warranty is over, your extended warranty kicks in and we can exchange the card ...  |O |O |O |O
You are welcome to open an RMA case in January next year and we will happily swap out the card. So sorry, there is nothing we can do, our chinese bosses dictate us how to go ahead. Many apologies, but we can confirm your card is under warranty until December 2024.

D'oh.
The card is now on the to be returned stack ... FFS ... argl ...
which means: do not break a Zotac card while it is under vendor warranty and make sure you register it for extended warranty, because that's the only way you can get it replaced.

Wow, what a way to impress your customers! :)
 

Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88332 on: April 16, 2021, 04:08:07 pm »
FETs aren't any better to be honest. Possibly even worse.

Fine example is the good old Radio Shack supplied MPF102 which makes its way into a bunch of ham projects. The Idss is specified at between 2mA and 20mA. Basically whatever FET came off the line gets that labelled on it. The result of this is lots of projects which don't work well and angry hams. The authors never explain that they actually had to buy a few and sub them before one actually worked in circuit well enough, because that doesn't sell magazines and books.

If you want a better range then you have to use the 2N5484/5/6 which is still specified at between 1-5, 4-10, 8-20mA respectively.

This is why you see "HP selected" and "Tek selected" FETs a lot in their early designs which are even tighter specified. They buy 10,000 better specified ones and then grade them separately and give them a vendor specific number. Still at the end of the day it's same silicon as a shitty MPF102 from Rat shack.

The HP427A is even nastier because to offset the gate leakage on the impedance converter FET they have a diode which is matched with it and temperature. Fortunately they don't ever seem to go wonky  :scared:

You're probably right but FET's do hold one significant advantage. They warm up and stabilize within a few minutes and don't require a burn-in. So once stabilized and adjusted you don't have to keep fiddling with them.
An old gray beard with an attitude.
 

Online Ice-Tea

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88333 on: April 16, 2021, 04:08:45 pm »
ok, nasty funngames ...

another RTX2070 blew up. Will crash after a couple of minutes, artifacts on the screen, after reboot it falls back to VGA.
Well, Zotac has 5 years warranty, does it not ...
Called Zotac: hey, my graphics card is misbehaving
ok, it is still under vendor warranty, contact mindfactory.
but they will only give me a refund, and I want the card repaired or swapped out ?
Well, their choice.
But I do have this extended warranty ?
Yes, but only after the normal warranty expires. We cannot accept the card right now.
but, if I RMA it via mindfactory, I don't get the card back, I'd rather have a working card instead of the purchase price in 2019 ...
Prices have tripled since then ...
weeeeeellll, you could put the card aside and wait for the vendor warranty to expire and then make use of the extended warranty. Once the vendor warranty is over, your extended warranty kicks in and we can exchange the card ...  |O |O |O |O
You are welcome to open an RMA case in January next year and we will happily swap out the card. So sorry, there is nothing we can do, our chinese bosses dictate us how to go ahead. Many apologies, but we can confirm your card is under warranty until December 2024.

D'oh.
The card is now on the to be returned stack ... FFS ... argl ...
which means: do not break a Zotac card while it is under vendor warranty and make sure you register it for extended warranty, because that's the only way you can get it replaced.

I can sell you my RX480 8GB if you wish. 500€ and it's yours! It's not like I have it mine at night recently on the free electricity in the building I rent. Promise.

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88334 on: April 16, 2021, 04:11:26 pm »
You're probably right but FET's do hold one significant advantage. They warm up and stabilize within a few minutes and don't require a burn-in. So once stabilized and adjusted you don't have to keep fiddling with them.

Yes that's true. But they don't keep you warm in winter. Well J310's do if you bias 'em wrong  :-DD
 

Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88335 on: April 16, 2021, 04:14:55 pm »
You're probably right but FET's do hold one significant advantage. They warm up and stabilize within a few minutes and don't require a burn-in. So once stabilized and adjusted you don't have to keep fiddling with them.

Yes that's true. But they don't keep you warm in winter. Well J310's do if you bias 'em wrong  :-DD

I hardly think that a nuvistor would keep a flea warm in the winter.  :P :-DD
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88336 on: April 16, 2021, 04:35:53 pm »
Urrrrk. Power just went oot. Utility's website sez "whole block is down, we don't know why, we don't know when it'll be back up."

Moo.

mnem
*toddles off to do something... outside*
« Last Edit: April 16, 2021, 04:57:13 pm by mnementh »
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Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88337 on: April 16, 2021, 04:53:00 pm »
Liking my shitty Intel GFX suddenly  :-DD
Yep, I've never ever thought that it was a wise thing to do, go for the cutting edge product, I always aim to be a few rungs down from that level so that they have had enough time to resolve any issues with it. I think I'll be hanging onto my card a bit longer.
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Offline Saskia

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88338 on: April 16, 2021, 05:15:14 pm »
I can sell you my RX480 8GB if you wish. 500€ and it's yours! It's not like I have it mine at night recently on the free electricity in the building I rent. Promise.

naah. I'll pass on this unless you throw in a 34401A. 500 for both would be ok and I would actually consider it.
 

Online Ice-Tea

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88339 on: April 16, 2021, 05:19:50 pm »
I could totally fake language confusion and charge you 500€ for both. Twice.  :-DD
 
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Offline Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88340 on: April 16, 2021, 05:32:17 pm »
In the early '50s, I was given Phenobarb, which may have worked, but gave me heart palpitations.

I think you've misremembered. That would have been ephedrine and phenobarbitol in combination. Ephedrine to treat the asthma, phenobarbitol to counter the methamphetamine like effects of the ephedrine, but only on the behavioural side of things and then only poorly; you still get all the somatic bad side effects of the ephedrine (high blood pressure, palpitations, sweating, insomnia, trembling and many more). I too was fed that evil combination in my youth.

The modern replacement for ephedrine, given when other things aren't working, is aminophylline (theophylline) and they hook you up to a cardiac monitor while they are giving you the loading dose and for a day or so until they are sure they have got the dose right. The therapeutic index (the difference between and effective dose and a dangerous dose: LD50/ED50) of aminophyline is about 3, one of the lowest of any drug in use (For cocaine it's 15, for morphine 70). i.e. Take three pills instead of the one you're supposed to and it'll probably kill you. That this has replaced ephedrine tells you all you need to know about the safety of ephedrine.

Not quite LD50, but paracetamol max allowed has been reduced to 65mg/kg/day. That's uncomfortably low for my (small) daughter.

IIRC if you exceed one (very safe) metabolic pathway removing the paracetamol, a different one becomes active and deposits formaldehyde in the liver. Oops.

The therapeutic index for paracetamol is 30 from memory. Paracetamol does indeed have several metabolic pathways through the liver. Metabolising paracetamol on one of those pathways depletes the liver's supply of glutathione  and it's when that's gone that it causes problems. The intermediate from before the step that uses up glutathione is what cause the problems producing  N-acetyl-p-benzoquinone imine. It's highly toxic to cell membranes and that's what does the damage. Paracetamol can be made much safer by administering a source of glutathione at the same time as the paracetamol, one commercial formulation was available (probably still is) which included enough methionine to provide sufficient glutathione to ensure that all the paracetamol could be metabolised safely. There have been calls for all paracetamol formulations to include methionine but so far they have fallen on deaf ears.

I think the formaldehyde thing you're thinking of is to do with the metabolism of ethanol versus methanol. Ethanol (C2H5OH) -> (alcohol dehydrogenase) -> acetaldehyde (CH3CHO). Methanol ((CH3OH))-> (alcohol dehydrogenase) -> formaldehyde (H-CHO). There's a pathway to detoxify acetaldehyde (-> (aldehyde dehydrogenase) -> acetate), there isn't one for formaldehyde.
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88341 on: April 16, 2021, 05:49:23 pm »
Metabolic side effects of paracetamol are easily sidestepped by popping a couple of 30mg codeine phosphate’s instead  :-DD.

Got given a box of them for my rib. Haven’t taken any yet as ibuprofen appears to be working fine. Will save them for when I’m bored  :-DD
 

Offline Saskia

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88342 on: April 16, 2021, 06:11:01 pm »
I could totally fake language confusion and charge you 500€ for both. Twice.  :-DD

umm, no ....
 

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88343 on: April 16, 2021, 06:15:16 pm »


Hmmmm...




Figures... just as I swap over all the power cables, and I'm reaching down to press the power button... the lights come back on.  :-DD

I have this little UPS I picked up my last thrifting venture just because it was $8 and it powered up immediately off the shelf; just hadn't gotten around to deploying, as I wanted to do some load-testing first. But after aboot an hour on my tablet, I decided to give it some live-fire testing. Of course, wasted effort...

mnem
Law of Irony, you win this round...  :o
« Last Edit: April 16, 2021, 06:18:04 pm by mnementh »
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88344 on: April 16, 2021, 06:22:19 pm »

I suspect what he meant was a LCR/ESR meter; as in a single device which combines the two functions. These are common nowadays, they weren't always.

When ESR meters as commonly used in electronics repair were first devised, they showed two parameters: Capacitance and ESR. They worked on capacitors, period.

Some LCR Meters, particularly older laboratory units, use a substitution bridge to determine the value of the DUT and don't actually offer ESR or Tan δ parameters.

It is only later models which can use the magic of cheap microprocessors and multiple ADCs which can offer all the above in a single device, even giving all these parameters in one test.

Or is that not the question you were asking...?

mnem
 :popcorn:

It would be really surprising to find a LCR meter that is not able to measure Rs. Even if they have different name, ESR is equal to Rs. All LCR meters can measure Rs. Even the old one.

Personally, I think ESR meters are useless when you have a good LCR meter. Maybe ESR meters have better range ?

I'm not sure why people tend to believe ESR meters actually measure something that LCR meters can't. The LCR meter is the superior instrument, ESR meter only measure a subset (Rs and if you are lucky Cs) of what a LCR meter can do.

I think it's the test parameters, and the inconvenience. ESR meters typically operate at one of several... well, I can't even call it a standard, as there really is no such thing... lets call it "commonly used" frequencies dependent upon capacitance range, such that results from one design of ESR meter are comparable to another.

Calculating it from Rs means knowing what frequency the LCR meter is running at right now, with this DUT, and it means that while you're diag-ing a PCB, every time you have to stop probing, pick up a pencil, and do some math to determine whether the cap is healthy or not.

What do you want to calculate here ? ESR == Rs. ESR is also dependent on frequency.

ESR as it is used on a repair bench boils all that down to a simpler, more repeatable result of ESR vs Capacitance which you can just eyeball, gauge whether it's reasonable, and move on to the next suspect component. Having used the DE-5000 for a couple years now, and being able to compare results from both test functions, I find that the Tan δ function is much more reliable as far as giving a definitive Yes/No answer, simply because if you aren't sure based on the internal "chart" one develops when using any such device, you can usually find this parameter in a MFR's datasheet.

I'm not questioning the use of ESR (Rs) here. And as you said, Tan δ (or D for Dissipation Factor) is most of the time more revealing.

The entire table of "acceptable ESR values" that people refer to is based on a chart created by Dick Smith decades ago, which unfortunately didn't include a LOT of today's Low and Ultra-Low ESR capacitor product lines. So what has evolved since is kindof a mishmash of both. That in and of itself is the main reason ESR as measured by an ESR meter is pretty useless from an enginerding standpoint.

That is also, I think, part of the reason Robert and I butted heads on this so hard (and keep doing so)... he's a hardcore engineer who has kept up with his professional development, so has a lot invested in knowing what he's doing, while I'm a retired engineer who was (a) never really that good at any of it except keeping several hundred circuits from a design in my head and (2) had to fall back on service & repair for my livelihood because I couldn't hack the modern corporate crazy-factory that is commercial/industrial engineering.  :-//

Sure ESR has been used in the industry for a long time and most components are not specified for  Tan δ (Dissipation Factor). Not sure why this is a justification for measuring ESR with a ESR meters when a LCR meter can do the same measurement  :-//

I'm just saying you don't need both. If you are only interested in ESR, get a ESR meter. They are normally cheaper than full blown LCR meter. If you want more measurements (Cp, D, I, etc ..), you probably want a LCR meter.

But I'm forgetting where i'm posting right now. A normal person should have at least 4 LCR meters and 4 ESR meters, just to be sure.  ;D

I think we're coming at the same point from different angles. Most modern LCR meters do, in fact, calculate it all for you at the same time. Then, the deciding factor becomes one of price vs intended use. What I've been arguing is not the value of ESR as a measurement; it has its place in on a repair bench for sure.

All I'm arguing is that the DE-5000 is a lot easier to use as an ESR meter in that scenario than the ESR70 for a host of reasons; as I own both and have a lot of experience with exactly that usage, I feel more qualified than most to answer that question. Added to that is the DE-5000 is one of the least expensive such meters, has a large user base with oodles of empirical evidence that it does exactly as claimed, and also that is it a more-than-serviceable entry level home-lab LCR meter.

I felt the DE-5000 was a particularly good choice in Iced-Tea's case, as the ESR function is well-documented as very good and it is not a chore to use like the ESR-70; which you have to place your probes, press a test button, wait for it to boot, do the test cycle, then scroll through a page or two for complete results every. single. time. you. test. a component. And often, all you get is "Invalid device or device not connected..." then you have to do the whole routine of power off, reposition probes, press button, wait... etc... again... Meanwhile, with the DE-5000, you set it to AUTO mode or select ESR, DCR, C, or L mode and just use the damned thing and it gives you results automatically, like a proper DMM.

He has access to numerous lab-quality LCR meters and can do a apples-apples comparison to decide for himself whether the accuracy of the DE-5000 as a entry-level lab LCR meter is adequate or suspect. If he can compare the results against one of those LCR meters, as a great many other users have done and claim it is more than good enough, then I believe that is far more telling than any opinions we can offer here.

One thing to note... which I feel is important evidence to the MFR's attention to detail... is that the DE-5000 does ESR as a separate test function from the usual capacitance/phase angle/loss/Tan δ; that is because it uses industry-standard test parameters for the former, while the "commonly-used frequencies" that are "standard" with ESR meters have little in common with those parameters.

As for the argument of what is a real DE-5000... so far I have yet to see anything that looks like real documented evidence that one or another is a "fake". I've seen some very minor changes that I feel are completely in line with usual product revision cycle for cost-cutting, parts availability and production; nothing more. Maybe Robert & bd139 have seen some discussion on that which I haven't; I'll admit I haven't frequented those threads much since I bought mine.  :-//

Honestly... most of the arguments I saw against the DE-5000 were little more than armchair QB-ing; people who had never even laid hands on one, so had no way of knowing whether they work or not, only that there was no traceable calibration and that they couldn't easily reverse-engineer it looking at pictures on the internet. I tend to take that kind of argument with a grain of salt, even when it comes from someone whose opinion I respect, like bd or Robert. I'm sure they have a whole slew of well-researched reasons why they don't want one; they've both touched on a few, but their angle is, IMO, more lab-oriented than mine. I think that's an important distinction here.

"I don't own one and I won't own one because..." is not valid empirical evidence. It is opinion based on guesswork. I do my own research, I decide, then I compare what I've found myself in my own use case against what others say. I found the evidence compelling enough to spend the pittance a DE-5000 costs, and made up my own mind.

I work very hard to avoid the whole "group-think" mess; it offends me on a visceral level. My complete aboot-face on the MS8911 is one such case in point; I was prepared to hate the thing after my experience with the MS8910. Similarly, I have considerably  reversed my opinion of the Cheap & Cheerful Chinese Hot Air Rework Stations... having used one of the cheapest 858D clones you can get, and found it more than serviceable for occasional use, I must admit I can't in good conscience recommend one of the better ones unless someone is using it for professional repair. :-//

At this point it really doesn't matter, as Iced-Tea has already ordered a DE-5000, hopefully from one of the "known-reputable" vendors out there. I personally welcome his feedback on it, and hope he decides to get a ESR70 on the way as well so he can offer feedback on that unit too. I've worn out my anvil beating on this one, so I intend to give it a rest. ;)

Cheers,

mnem
 :popcorn:
« Last Edit: April 16, 2021, 06:33:14 pm by mnementh »
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Online Ice-Tea

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88345 on: April 16, 2021, 06:26:50 pm »
I could totally fake language confusion and charge you 500€ for both. Twice.  :-DD

umm, no ....

Argh, Germans and humor  :-//

At some point in the past, I had several boxes of MXM laptop graphics cards in stock. Around 500 pieces or so in total. I suppose I had a better chance of seducing you at that time ;)

Or, if I understand correctly, with a sufficiently low priced 34401 ;)

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88346 on: April 16, 2021, 06:30:32 pm »
Yes that's an explanation reserved for wives  :popcorn:
I want to be a fly on the wall when the explanation is attempted and how well it is received.  I suspect it will go over like a fart in church.   :-DD



Easy-peasy... >:D

mnem
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Online tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88347 on: April 16, 2021, 06:41:21 pm »
Metabolic side effects of paracetamol are easily sidestepped by popping a couple of 30mg codeine phosphate’s instead  :-DD.

Got given a box of them for my rib. Haven’t taken any yet as ibuprofen appears to be working fine. Will save them for when I’m bored  :-DD

Somebody I knew at school got hooked on codeine and had difficulties getting off it!

I've got several strong-ish painkillers that I was given after various operations. I think I took some on one occasion.
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Offline Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88348 on: April 16, 2021, 06:42:59 pm »


I think the  Necromancer's Creed applies: "Do not call up that which you cannot also put down."

Anybody got a syringe I can use to squeeze the magic smoke back into this?
 
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Offline 25 CPS

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #88349 on: April 16, 2021, 06:46:04 pm »
I mentioned previously that I noticed that nuvistors need a lot of burn-in time to become stable. So I wanted to conduct a quick experiment with the 2 supposedly tested 7586 nuvistors I received last week. I don't know how they were tested or how long ago. And I suspect if they were tested it was nothing more than a quick emission test. So let's see what happens when plugged in the Type 321A.

Baseline measurement: The current 7586 installed as it warms up comes from off screen at the bottom and after about 5 or 10 minutes settles and stabilizes on center line.

Spare nuvistor number 1:  After 10 minutes was still off screen at the bottom. Had to adjust vertical position off center to get it on screen. And could not adjust it off screen at the top. But square wave trace looked good. So in order the center this for equal deflection would require fiddling with the DC balance and possibly the gain.


Spare nuvistor number 2:  Warmed up and trace went from bottom all the way off screen at the top. Could not get it on screen with the vertical position. This nuvistor has a large DC offset and in fact may be defective. I think it would take considerable fiddling with the DC balance to get it on screen.     


So, quick conclusion. These nuvistors are flaky as hell and anytime one is replaced considerable adjustment is going to be required. I'm glad FET's replaced them. 




Yikes, the four channel amplifier that came with the 564B uses eight of the the bloody things in the font end.

I still need to haul that stuff in from the car but I need to shuffle things around downstairs to make space first.  Then they're going to go on the bench one at a time to see what the score is with each one.  The upshot is it is Friday which means weekend and right now that's very important.
 
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