Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 14572529 times)

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Offline Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112200 on: January 25, 2022, 03:53:22 pm »
felt quite rotten over the week end. Headache, joint aches, slight fever, coughing, nose clogged.
C rapid test negative, boss told me to get a PCR test.
Doctor said: no positive rapid antigene test, no PCR test.

D'oh.

In other news negotiating for a PAT (made by Megger).
Is Megger a reputable company ?

Ah, sounds like you need a new doctor who understands this new-fangled rapid antigen testing. The sensitivity of one of the commonly used LFTs in the UK (Innova) is just over 75% for people with moderate viral loads and 95% for people with high viral loads. Translated into false negatives that means that a LFT will give a false negative for 25% of cases with a moderate viral load (1 in 4), and 5% for cases with a high viral load (1 in 20). The same test has a specificity of 99.68% (meaning that in only 0.32% of cases would it yield a false positive when presented with a high viral load sample of something other than SARS-Cov-2 antigens).

It's worth noting that the sensitivities quoted are for tests performed by laboratory scientists trained and experienced in doing these kind of tests. Porton Down found that a 79% sensitivity when the tests were performed by experienced lab technicians reduced to 73% when performed by trained healthcare workers and only 58% when performed by "self-trained members of the public" (i.e. those who only had the leaflet for instruction). So in practice, the false positive rates will be higher than those given in the first paragraph above which are "lab technician" figures. So probably closer to 1 in 3 false negatives for members of the public with moderate viral loads testing themselves.

And Megger are highly reputable. Sufficiently so that British elec-chickens call an insulation tester "a Megger" (cf Hoover versus vacuum cleaner). If your doctor was an insulation tester he/she would be a "Happy Lucky Factory No. 888" tester, not a "Megger".
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 
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Offline Vince

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112201 on: January 25, 2022, 03:58:45 pm »
Wow looks likze I finally found my bench DMM !

https://www.leboncoin.fr/equipements_industriels/2104828351.htm

A 34401A DMM for half price ?!  250 Euros ! Guy pretends it works... looks like new, it's a modern Agilent branded one, VFD looks even an bright... what's the catch ? These HP DMM/counter/DDS usually sell for twice that, 500 Euros..; or have prices plummeted recently and nobody told me ?

Maybe it's fucked .. but then same goes for all the other ones sold at 500 so...





i contacted the seller but after a small chat it looked like a scam to me ... be careful

More and more scam on this website regarding Lab Equipment.

Ah thanks, you got luckier than me then... guy still has not even read my message  :-\

I guess I better stop dreaming and keep my money that I don't even have then...
DC loads and bench DMM are not in short supply, I can always buy one any time later.
It's not like it was a rare vintage piece of gear that pops up once every 20 years...

You can ask Ray what he wants for Fluke 8505/6A with GPIB.


Oh I am not looking at spending "big" money on f TE right now, zero money for that.
I was contemplating that 34401 because it was a modern Agilent version of it and half price, so a super bargain.
So was willing to dig in my credit card to not let this opportunity pass... but that's all.
I am in fact quite relieved that this is a scam and now giving up on it... as it will keep me from making my already scary financial situation... any worse.

 

Offline Vince

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112202 on: January 25, 2022, 04:28:39 pm »
I don't think B/W is the problem here, plenty enough signal amplitude.. looks more like a tired trigger circuit and I have no idea how to fix / diagnose that... no schematics around for the 544A, well unless it leaked since 5 years ago when I worked on it. Think I found schematics from a 520 or something, something like that... better than nothing... but still only partial schematic, so don't don't know it they show the trigger circuitry...

Anyway regardless, would be cool upping the B/W if it's just a cap to remove on the front end.. even if in practice it's not going to make much of a difference since the sampling rate and sweep sweep won't increase accordingly to make use of the extra B/W....
But for repetitive signals I guess it could still be somewhat useful.

Bring it on, give me instructions !  >:D

SPC ? No I didn't do that... I ran it 10 times in a row 5 years ago after fixing the scope, to make sure it was working fine... but have not run it ever since... OK will try that, though from memory it has nothing to do with triggering, SPC only compensates for small temperature induced DC offsets in the signal path ?  Just from memory...
But it's free to try so will do !


FW versions ?
OK just powered them up to check... here goes :

TDS 544A:   v3.8.3e with options 13 1F M
TDS 694C:   v6.4e   with options 13 1F 2F



Would be cool to extract the FW through GPIB, never done it ! Gimme the S/W and instructions even if you are not interested in my crusty old FW !  :-DD

Here's a link to TDS554A schematics, in the sidebar on the right: :)
https://w140.com/tekwiki/wiki/TDS544A

Here's a link to some info on the TDS694C, it mentions a common issue with the triggering, maybe yours needs some love?
https://w140.com/tekwiki/wiki/TDS694

For the downloading of the firmware (and uploading of newer firmware), check this link:
https://www.eevblog.com/forum/repair/unified-tektool-released-!-(firmware-flash-tools-for-old-tds-series)/msg3758918/#msg3758918

I'll take both those firmwares if you can extract them.
The newest TDS6xx firmware I have is 4.2e, and I don't have TDS5xx 3.8.3e yet either. I've attached 3.8.4e firmware if you want to do a little upgrade too. It will take about 45 mins to upload, downloading is much faster (make sure to pull down the NVRAM as well as the firmware as in the instructions, that way it's basically impossible to brick your scope).


Also, follow this one to enable extra options:
Try the 2M option on the TDS694C, if it doesn't work, set it back to 0 and try 1M, and set 2F on the TDS544A.


Thanks a bunch for all that, you rock !  :-+

So the  544A schematics finally "leaked" then, that's fantastic ! Especially so since VintageTek museum said that despite them scanning their mega huge archive of Tek microfiches, they found no schematics for the 500/700 series, IIRC ! 

OK will play with FW and GPIB when I can... that is, not before some time... lab is no where near a state where I can clutter it with my old Pentium / GPIB PC....
When I get to that point, hopefully within 3 months, I will think of you ! If I don't... send me a PM !  ;D

OK running SPC was a good idea in fat, you were right...
Let the scope warm up for 20/25 minutes (they say 15  minutes minimum), ran SPC, got 3 errors. Let it warm up 20 more minutes, ran SPC again, got the exact same 3 errors, no more no less. The first two ones don't seem critical to me / relevant to my problem, but the last one looks like it is ! See screen capture below, it says that the trigger section failed to calibrate !!!  |O
Without a PROPER service manual, to explain how the trigger circuit works and how to check for proper operation... no hope of fixing it.
My only hope of fixing it is that there is some corrosion that slowly progressed over the years.

Being a 5XX 'A', it is plagued with the dreaded myriad of leaky SMD electrolytic caps. ShakalNokturn who sold me the scope 5 year ago did a lot of work to bring it back from the dead.. replaced all caps, washed the boards several times in the dish washer, then fixed many broken traces in the analog part of the acquisition board, with a level of craftsmanship I envy.  That got it working... but I still had weird errors, semi random, in the error log. So I looked at the corroded/reworked analog area that he fixed. I eventually found on the underside of the board, were these is nothing but a handful of discrete components IIRC... that a few SMD resistors had crappy looking/dull solder joints. Touched them up and that got rid of any and all error messages !  :D  The dodgy joints were near a via. I suspect that the electrolyte managed to seep through these tiny open via and contaminated the bottom side of the board.

So.... since the trigger circuitry on these scopes IRC is all analog not digital, it's probably located in the same area that's been reworked / fixed. So all I can do is look at that area again and search for dodgy joints, rotten traces and what not. However since 99.9999% of hte work has already been done, it probably means that whatever problem remains, is bound to be NON obvious/blatant, so will need very careful inspection. Yes, this is a job for microscope. When I first fixed that board 5 years ago II suffered so much when going over that board, that I promised to myself I would NEVER do it again, to preserve my sanity (en eye balls).
So I will only look at this board... once I can afford to buy a microscope. No please people don't tell me about optivisor or what not. I have that... rubbish. I want/need to inspect this board in great detail, at length, in comfort.  I am not looking at rushing this inspection, to the contrary I want to take my time and do properly when I am equipped to do so.  Scope works fine below 400MHz so it's not like it was bricked... plus I rarely need it anyway. 99.99% of the time I just use my Combiscope...


 
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112203 on: January 25, 2022, 04:33:09 pm »
Ah, sounds like you need a new doctor who understands this new-fangled rapid antigen testing. The sensitivity of one of the commonly used LFTs in the UK (Innova) is just over 75% for people with moderate viral loads and 95% for people with high viral loads. Translated into false negatives that means that a LFT will give a false negative for 25% of cases with a moderate viral load (1 in 4), and 5% for cases with a high viral load (1 in 20). The same test has a specificity of 99.68% (meaning that in only 0.32% of cases would it yield a false positive when presented with a high viral load sample of something other than SARS-Cov-2 antigens).

It's worth noting that the sensitivities quoted are for tests performed by laboratory scientists trained and experienced in doing these kind of tests. Porton Down found that a 79% sensitivity when the tests were performed by experienced lab technicians reduced to 73% when performed by trained healthcare workers and only 58% when performed by "self-trained members of the public" (i.e. those who only had the leaflet for instruction). So in practice, the false positive rates will be higher than those given in the first paragraph above which are "lab technician" figures. So probably closer to 1 in 3 false negatives for members of the public with moderate viral loads testing themselves...
Hmmm... how does blood contamination of the sample affect these numbers? The boi's test was positive, but he's shown no symptoms other than sniffles, and since then even that is gone. He does, however, have a history of nosebleeds, and def had one less than a day prior; while nothing visible to the eye at the time of the sample, high probability of some amounts of blood in the sample. :-//

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« Last Edit: January 25, 2022, 04:38:41 pm by mnementh »
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Offline tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112204 on: January 25, 2022, 04:39:33 pm »
felt quite rotten over the week end. Headache, joint aches, slight fever, coughing, nose clogged.
C rapid test negative, boss told me to get a PCR test.
Doctor said: no positive rapid antigene test, no PCR test.

D'oh.

In other news negotiating for a PAT (made by Megger).
Is Megger a reputable company ?

Ah, sounds like you need a new doctor who understands this new-fangled rapid antigen testing. The sensitivity of one of the commonly used LFTs in the UK (Innova) is just over 75% for people with moderate viral loads and 95% for people with high viral loads. Translated into false negatives that means that a LFT will give a false negative for 25% of cases with a moderate viral load (1 in 4), and 5% for cases with a high viral load (1 in 20). The same test has a specificity of 99.68% (meaning that in only 0.32% of cases would it yield a false positive when presented with a high viral load sample of something other than SARS-Cov-2 antigens).

It's worth noting that the sensitivities quoted are for tests performed by laboratory scientists trained and experienced in doing these kind of tests. Porton Down found that a 79% sensitivity when the tests were performed by experienced lab technicians reduced to 73% when performed by trained healthcare workers and only 58% when performed by "self-trained members of the public" (i.e. those who only had the leaflet for instruction). So in practice, the false positive rates will be higher than those given in the first paragraph above which are "lab technician" figures. So probably closer to 1 in 3 false negatives for members of the public with moderate viral loads testing themselves.

And Megger are highly reputable. Sufficiently so that British elec-chickens call an insulation tester "a Megger" (cf Hoover versus vacuum cleaner). If your doctor was an insulation tester he/she would be a "Happy Lucky Factory No. 888" tester, not a "Megger".
Hmmm... how does blood contamination of the sample affect these numbers? The boi's test was positive, but he's shown no symptoms other than sniffles, and since then even that is gone. He does, however, have a history of nosebleeds, and def had one less than a day prior; while nothing visible to the eye at the time of the sample, high probability of some amounts of blood in the sample. :-//

Daughter had a false positive due to swabbing her nose (not tonsils) and someone looking at the strip after 45 mins. The spec for the time delay is 15min is sufficient for a positive test, 30 mins for a negative, and ignore positives seen after 30 mins.
There are lies, damned lies, statistics - and ADC/DAC specs.
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Offline Vince

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112205 on: January 25, 2022, 04:43:30 pm »
VARTA battery.

AM going to try dwagon's 7805 trick to constant current discharge the battery, just for fun.

So nice to see that my big box of random salvage semi-conductors might be useful !

Let's see what I can find in there !

Emptied it all on the bench, pulled all the TO220 looking packages I could find, sorted them... hey presto, found no less than 34 78/79 regulators, of which 15 were 7805 !  8)
Surely at least one of them must be working....

As I was looking at every TO220 package to find the 78/79, every time I read "IRF" I though to myself  "fuck me, must be a MOSFET and I just killed it just by handling it ". Oh well, you gotta have casualties I guess...  :-//

No that I spent time sorting these regulators, no way i hell I am putting them back in the box ! So will put them in a separate box... I didn't plan on starting to sort my components just now, wanted to leave that 'til the end, but I guess this is the start of it ! So, at least a little bit of it has now been done...  8)

Let's go wire that up on the breadboard see if that works....
 
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Offline TERRA Operative

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112206 on: January 25, 2022, 04:43:53 pm »
I don't think B/W is the problem here, plenty enough signal amplitude.. looks more like a tired trigger circuit and I have no idea how to fix / diagnose that... no schematics around for the 544A, well unless it leaked since 5 years ago when I worked on it. Think I found schematics from a 520 or something, something like that... better than nothing... but still only partial schematic, so don't don't know it they show the trigger circuitry...

Anyway regardless, would be cool upping the B/W if it's just a cap to remove on the front end.. even if in practice it's not going to make much of a difference since the sampling rate and sweep sweep won't increase accordingly to make use of the extra B/W....
But for repetitive signals I guess it could still be somewhat useful.

Bring it on, give me instructions !  >:D

SPC ? No I didn't do that... I ran it 10 times in a row 5 years ago after fixing the scope, to make sure it was working fine... but have not run it ever since... OK will try that, though from memory it has nothing to do with triggering, SPC only compensates for small temperature induced DC offsets in the signal path ?  Just from memory...
But it's free to try so will do !


FW versions ?
OK just powered them up to check... here goes :

TDS 544A:   v3.8.3e with options 13 1F M
TDS 694C:   v6.4e   with options 13 1F 2F



Would be cool to extract the FW through GPIB, never done it ! Gimme the S/W and instructions even if you are not interested in my crusty old FW !  :-DD

Here's a link to TDS554A schematics, in the sidebar on the right: :)
https://w140.com/tekwiki/wiki/TDS544A

Here's a link to some info on the TDS694C, it mentions a common issue with the triggering, maybe yours needs some love?
https://w140.com/tekwiki/wiki/TDS694

For the downloading of the firmware (and uploading of newer firmware), check this link:
https://www.eevblog.com/forum/repair/unified-tektool-released-!-(firmware-flash-tools-for-old-tds-series)/msg3758918/#msg3758918

I'll take both those firmwares if you can extract them.
The newest TDS6xx firmware I have is 4.2e, and I don't have TDS5xx 3.8.3e yet either. I've attached 3.8.4e firmware if you want to do a little upgrade too. It will take about 45 mins to upload, downloading is much faster (make sure to pull down the NVRAM as well as the firmware as in the instructions, that way it's basically impossible to brick your scope).


Also, follow this one to enable extra options:
Try the 2M option on the TDS694C, if it doesn't work, set it back to 0 and try 1M, and set 2F on the TDS544A.


Thanks a bunch for all that, you rock !  :-+

So the  544A schematics finally "leaked" then, that's fantastic ! Especially so since VintageTek museum said that despite them scanning their mega huge archive of Tek microfiches, they found no schematics for the 500/700 series, IIRC ! 

OK will play with FW and GPIB when I can... that is, not before some time... lab is no where near a state where I can clutter it with my old Pentium / GPIB PC....
When I get to that point, hopefully within 3 months, I will think of you ! If I don't... send me a PM !  ;D

OK running SPC was a good idea in fat, you were right...
Let the scope warm up for 20/25 minutes (they say 15  minutes minimum), ran SPC, got 3 errors. Let it warm up 20 more minutes, ran SPC again, got the exact same 3 errors, no more no less. The first two ones don't seem critical to me / relevant to my problem, but the last one looks like it is ! See screen capture below, it says that the trigger section failed to calibrate !!!  |O
Without a PROPER service manual, to explain how the trigger circuit works and how to check for proper operation... no hope of fixing it.
My only hope of fixing it is that there is some corrosion that slowly progressed over the years.

Being a 5XX 'A', it is plagued with the dreaded myriad of leaky SMD electrolytic caps. ShakalNokturn who sold me the scope 5 year ago did a lot of work to bring it back from the dead.. replaced all caps, washed the boards several times in the dish washer, then fixed many broken traces in the analog part of the acquisition board, with a level of craftsmanship I envy.  That got it working... but I still had weird errors, semi random, in the error log. So I looked at the corroded/reworked analog area that he fixed. I eventually found on the underside of the board, were these is nothing but a handful of discrete components IIRC... that a few SMD resistors had crappy looking/dull solder joints. Touched them up and that got rid of any and all error messages !  :D  The dodgy joints were near a via. I suspect that the electrolyte managed to seep through these tiny open via and contaminated the bottom side of the board.

So.... since the trigger circuitry on these scopes IRC is all analog not digital, it's probably located in the same area that's been reworked / fixed. So all I can do is look at that area again and search for dodgy joints, rotten traces and what not. However since 99.9999% of hte work has already been done, it probably means that whatever problem remains, is bound to be NON obvious/blatant, so will need very careful inspection. Yes, this is a job for microscope. When I first fixed that board 5 years ago II suffered so much when going over that board, that I promised to myself I would NEVER do it again, to preserve my sanity (en eye balls).
So I will only look at this board... once I can afford to buy a microscope. No please people don't tell me about optivisor or what not. I have that... rubbish. I want/need to inspect this board in great detail, at length, in comfort.  I am not looking at rushing this inspection, to the contrary I want to take my time and do properly when I am equipped to do so.  Scope works fine below 400MHz so it's not like it was bricked... plus I rarely need it anyway. 99.99% of the time I just use my Combiscope...




That first and second error usually indicate the usual worn out relay problem on the input hybrids for the 600 and 700 series, they are still available from your favourite parts outlet and aren't toooo difficult to replace. I've done two scopes so far. Best to just replace them all while you are in the unit, to avoid disturbing the slightly delicate hybrids too much.
youtube.com/watch?v=b0P1sJBomDQ
I'd be interested to see the setup for the 500 series hybrids as it appears to be on a separate PCB to the acquisition board rather than all integrated on the one PCB like the 600 and 700 series. I assume there would be some sort of range switching in there.

Good luck with the rest of the repairs, the 500 series is rather different to the 600 and 700 series on the acquisition board, and I haven't come across one yet. I think you might be on the right track with the residual electrolyte damage though, that stuff is hard to get out once it's soaked in.

Double check my last post, I added some links since your quoted message.
Where does all this test equipment keep coming from?!?

https://www.youtube.com/NearFarMedia/
 

Offline Zucca

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112207 on: January 25, 2022, 04:46:11 pm »
What editor you like the most
  • vi
  • nano
  • emacs
?
Can't know what you don't love. St. Augustine
Can't love what you don't know. Zucca
 

Offline Vince

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112208 on: January 25, 2022, 04:49:05 pm »
What editor you like the most
  • vi
  • nano
  • emacs
?


Have no preference, I am using XFCE on Ubuntu and it comes with " Leafpad " and " Mousepad ", so I just use that !   :-DD

I know I know... I was not the target audience of your survey !  :-DD

 

Offline dl6lr

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112209 on: January 25, 2022, 04:49:29 pm »
I have seen one of these China "Keysight" USB GPIB... They are very impressive, come in a convincing cardboard box, all the paperwork is inside like expected, the device itself looks spotless.

Made in Malaysia printed on the box. You expect a "Ceryificate" inside the box, don't you?  :-DD
Don't ask how I know... Mine is still labelled Agilent.

And yes, they normally work.

 
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Offline Zucca

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112210 on: January 25, 2022, 04:52:02 pm »
oh I found already an editor battle 2000 years pages ago...

I go back to study history.
« Last Edit: January 25, 2022, 04:58:39 pm by Zucca »
Can't know what you don't love. St. Augustine
Can't love what you don't know. Zucca
 
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Offline Vince

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112211 on: January 25, 2022, 04:57:40 pm »
Thanks a bunch for all that, you rock !  :-+

OK running SPC was a good idea in fat, you were right...
Let the scope warm up for 20/25 minutes (they say 15  minutes minimum), ran SPC, got 3 errors. Let it warm up 20 more minutes, ran SPC again, got the exact same 3 errors, no more no less. The first two ones don't seem critical to me / relevant to my problem, but the last one looks like it is ! See screen capture below, it says that the trigger section failed to calibrate !!!  |O
Without a PROPER service manual, to explain how the trigger circuit works and how to check for proper operation... no hope of fixing it.
My only hope of fixing it is that there is some corrosion that slowly progressed over the years.

Being a 5XX 'A', it is plagued with the dreaded myriad of leaky SMD electrolytic caps. ShakalNokturn who sold me the scope 5 year ago did a lot of work to bring it back from the dead.. replaced all caps, washed the boards several times in the dish washer, then fixed many broken traces in the analog part of the acquisition board, with a level of craftsmanship I envy.  That got it working... but I still had weird errors, semi random, in the error log. So I looked at the corroded/reworked analog area that he fixed. I eventually found on the underside of the board, were these is nothing but a handful of discrete components IIRC... that a few SMD resistors had crappy looking/dull solder joints. Touched them up and that got rid of any and all error messages !  :D  The dodgy joints were near a via. I suspect that the electrolyte managed to seep through these tiny open via and contaminated the bottom side of the board.

So.... since the trigger circuitry on these scopes IRC is all analog not digital, it's probably located in the same area that's been reworked / fixed. So all I can do is look at that area again and search for dodgy joints, rotten traces and what not. However since 99.9999% of hte work has already been done, it probably means that whatever problem remains, is bound to be NON obvious/blatant, so will need very careful inspection. Yes, this is a job for microscope. When I first fixed that board 5 years ago II suffered so much when going over that board, that I promised to myself I would NEVER do it again, to preserve my sanity (en eye balls).
So I will only look at this board... once I can afford to buy a microscope. No please people don't tell me about optivisor or what not. I have that... rubbish. I want/need to inspect this board in great detail, at length, in comfort.  I am not looking at rushing this inspection, to the contrary I want to take my time and do properly when I am equipped to do so.  Scope works fine below 400MHz so it's not like it was bricked... plus I rarely need it anyway. 99.99% of the time I just use my Combiscope...




That first and second error usually indicate the usual worn out relay problem on the input hybrids for the 600 and 700 series, they are still available from your favourite parts outlet and aren't toooo difficult to replace. I've done two scopes so far. Best to just replace them all while you are in the unit, to avoid disturbing the slightly delicate hybrids too much.
youtube.com/watch?v=b0P1sJBomDQ
I'd be interested to see the setup for the 500 series hybrids as it appears to be on a separate PCB to the acquisition board rather than all integrated on the one PCB like the 600 and 700 series. I assume there would be some sort of range switching in there.

Good luck with the rest of the repairs, the 500 series is rather different to the 600 and 700 series on the acquisition board, and I haven't come across one yet. I think you might be on the right track with the residual electrolyte damage though, that stuff is hard to get out once it's soaked in.

Double check my last post, I added some links since your quoted message.

Thanks.

Doing the relays is quite a job and will cost money... so not sure it's worth it given long term I plan on getting rid of the scope in search of a 784D or 794D....
Will look into it anyway... because it probably will be  a few years before I can afford a 784D...

As for the hybrids I guess you are talking about the die cast box... so you will have to wait until I look into the relays to see what's inside, sorry !  :-[
... but I am sure there must be pics or YT videos about it somewhere....

 

Offline Zucca

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112212 on: January 25, 2022, 04:58:13 pm »
Found a teardown of the original shorting plug: https://www.eevblog.com/forum/metrology/keithley-1488-low-thermal-shorting-plug-(a-quick-teardown)/

It seems like the input connector has copper plated connection so mine is probably not an original at all.

Atomillo mira chico....
I believe maybe the metrology section is the right for you.
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Offline mansaxel

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112213 on: January 25, 2022, 04:58:43 pm »
What editor you like the most
  • vi
  • nano
  • emacs
?

nano is a piece of shit, a rewrite of a piece of shit (pico) that had a license that limited its dissipation. Its use and more so its promotion should be punished with thermonuclear means.  Case in point; when a sysadmin article says "sudo nano" you know that you must parse it through the "Remove Fisher-Price toy formatting" filter (a.k.a "Ubuntu", the Zulu word for "I can't install Devuan") and sort of imagine all the grown-up parts that the author left out.

emacs is useful, and like a 5-axis CNC machine, something that will make a lot of output when you've spent a week setting it up. Or, you can live in it. I know people who tried to run emacs instead of init. It won't handle child processes that die very well, so there were lots of zombies.

vi depends. if it is "vim" it secretly wants to become emacs and that's just silly. If it is "nvi" or plain BSD vi, it's kosher.

I find that I a lot of times simply fire up "ed" to write short things. 

Offline Vince

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112214 on: January 25, 2022, 04:59:56 pm »
I have seen one of these China "Keysight" USB GPIB... They are very impressive, come in a convincing cardboard box, all the paperwork is inside like expected, the device itself looks spotless.

Made in Malaysia printed on the box. You expect a "Ceryificate" inside the box, don't you?  :-DD
Don't ask how I know... Mine is still labelled Agilent.

And yes, they normally work.

I might be tempted by one of these, so I can use GPIB on a modern computer rather than having to use an old bulky dedicated Pentium box... do you have a link to one of these adapters that I could check out ?

 

Offline mansaxel

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112215 on: January 25, 2022, 05:04:33 pm »
TE content:

My 465 lives again. The Würth 33µF cap holds and works.  All voltages except +110VDC are in-spec; the +110VDC is like 30mV high and I don't think it worth to dig into ATM. (the Würth sits on the +15V on the trigger board.)

Also, the USMC Fluke 27 got first live use with the smaller HV probe; +2450VDC is in spec.

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112216 on: January 25, 2022, 05:05:02 pm »
Hmmm... how does blood contamination of the sample affect these numbers? The boi's test was positive, but he's shown no symptoms other than sniffles, and since then even that is gone. He does, however, have a history of nosebleeds, and def had one less than a day prior; while nothing visible to the eye at the time of the sample, high probability of some amounts of blood in the sample. :-//

Daughter had a false positive due to swabbing her nose (not tonsils) and someone looking at the strip after 45 mins. The spec for the time delay is 15min is sufficient for a positive test, 30 mins for a negative, and ignore positives seen after 30 mins.
Yeah, these home antigen tests are for nasal sampling (specifically: SARS-Cov2 nucleocapsid protein antigen); the directions are very detailed and the swab is too short to reach a tonsil anyways. The directions are much more specific on reading the sample as well; mix/extract/drop the sample immediately after swabbing, read at between 10 & 15 minutes after dropping the reagent/sample into the cassette: No more, no less.

mnem
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Offline Atomillo

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112217 on: January 25, 2022, 05:09:06 pm »
(...)

I will do! I thought of covering it with a small pot filled with cotton to act as thermal insulator.
The thermal EMFs after touching the short are very visible. In my case it took around 5 or 6 minutes to "change direction".
Now I'm starting to really wish having a GPIB USB adaptor... But new are extremely expensive, and the options from eBay coming from China from around 150 euros as "new" seem suspicious.
I have seen one of these China "Keysight" USB GPIB... They are very impressive, come in a convincing cardboard box, all the paperwork is inside like expected, the device itself looks spotless.
If you unboxed new Agilent/Keysight stuff, it looks 100% the same.
There have been some troubles with too small traces breaking inside, but that was a few years ago - I would guess they have it worked out by now?

Did they actually work?
I've seen this:
https://www.ebay.es/itm/Applicable-for-82357b-GPIb-to-USB-Card-82357b-IEEE-488-test-lead-/372691758243?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l6249&mkrid=707-127634-2357-0

Where they pixelate the Keysight logo. It also helps that it has guarantee.
Sadly, we did not test it thoroughly. At first glance it sure did seem to work, was recognized by all the software. It looked more like this.
IMHO this is only a "good investment" IF you are dependent on Labview / other premade software that expects this kind of device.
See the edit on my comment above if you are not scared to write e.g. a python script to get your data - less waiting & much cheaper.

It seems quite promising! Like a lot of things I've gotten into, I expected interfacing with a computer to be a simple affair. I've heard it was the industry standard so I expected an unified set of easily understandable commands, common controllers, etc...

Also like pretty much all the things I've started without proper research, my assumptions were essentially incorrect  |O
 
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112218 on: January 25, 2022, 05:09:43 pm »
What editor you like the most
  • vi
  • nano
  • emacs
?

nano is a piece of shit, a rewrite of a piece of shit (pico) that had a license that limited its dissipation. Its use and more so its promotion should be punished with thermonuclear means.  Case in point; when a sysadmin article says "sudo nano" you know that you must parse it through the "Remove Fisher-Price toy formatting" filter (a.k.a "Ubuntu", the Zulu word for "I can't install Devuan") and sort of imagine all the grown-up parts that the author left out.

emacs is useful, and like a 5-axis CNC machine, something that will make a lot of output when you've spent a week setting it up. Or, you can live in it. I know people who tried to run emacs instead of init. It won't handle child processes that die very well, so there were lots of zombies.

vi depends. if it is "vim" it secretly wants to become emacs and that's just silly. If it is "nvi" or plain BSD vi, it's kosher.

I find that I a lot of times simply fire up "ed" to write short things.
Windoze PowerShell.  >:D

mnem
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« Last Edit: January 25, 2022, 05:12:58 pm by mnementh »
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Offline BU508A

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112219 on: January 25, 2022, 05:20:01 pm »
What editor you like the most
  • vi
  • nano
  • emacs
?

vi or vim here.
emacs is an OS disguised as an editor.
I tried nano once, hated it (forgot the reason) and never tried again.
“Chaos is found in greatest abundance wherever order is being sought. It always defeats order, because it is better organized.”            - Terry Pratchett -
 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112220 on: January 25, 2022, 05:27:05 pm »
PCR Test tomorrow. Doc said that symptoms are in line with omicron version, however they need to ration the PCR tests. They would get me one in this case.


I think the real reason for rationing the PCR tests is that if they don't carry out so many tests, then they also will not be recording so many positives and thus fool the public into thinking that Covid has been beaten  >:D
Who let Murphy in?

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Offline Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112221 on: January 25, 2022, 05:28:49 pm »
What editor you like the most
  • vi
  • nano
  • emacs
?

TECO.  >:D

Quote from: Real Programmers Don't Use Pascal
In some companies, text editing no longer consists of ten engineers standing in line to use an 029 keypunch. In fact, the building I work in doesn't contain a single keypunch. The Real Programmer in this situation has to do his work with a "text editor" program. Most systems supply several text editors to select from, and the Real Programmer must be careful to pick one that reflects his personal style. Many people believe that the best text editors in the world were written at Xerox Palo Alto Research Center for use on their Alto and Dorado computers [3]. Unfortunately, no Real Programmer would ever use a computer whose operating system is called SmallTalk, and would certainly not talk to the computer with a mouse.

Some of the concepts in these Xerox editors have been incorporated into editors running on more reasonably named operating systems -- EMACS and VI being two. The problem with these editors is that Real Programmers consider "what you see is what you get" to be just as bad a concept in Text Editors as it is in women. No the Real Programmer wants a "you asked for it, you got it" text editor -- complicated, cryptic, powerful, unforgiving, dangerous. TECO, to be precise.

It has been observed that a TECO command sequence more closely resembles transmission line noise than readable text [4]. One of the more entertaining games to play with TECO is to type your name in as a command line and try to guess what it does. Just about any possible typing error while talking with TECO will probably destroy your program, or even worse -- introduce subtle and mysterious bugs in a once working subroutine.

Also:

Quote from: Real Programmers Don't Use Pascal
The easiest way to tell a Real Programmer from the crowd is by the programming language he (or she) uses. Real Programmers use FORTRAN. Quiche Eaters use PASCAL. Nicklaus Wirth, the designer of PASCAL, gave a talk once at which he was asked "How do you pronounce your name?". He replied, "You can either call me by name, pronouncing it 'Veert', or call me by value, 'Worth'." One can tell immediately from this comment that Nicklaus Wirth is a Quiche Eater. The only parameter passing mechanism endorsed by Real Programmers is call-by-value-return, as implemented in the IBM\370 FORTRAN-G and H compilers. Real programmers don't need all these abstract concepts to get their jobs done -- they are perfectly happy with a keypunch, a FORTRAN IV compiler, and a beer.
  • Real Programmers do List Processing in FORTRAN.
  • Real Programmers do String Manipulation in FORTRAN.
  • Real Programmers do Accounting (if they do it at all) in FORTRAN.
  • Real Programmers do Artificial Intelligence programs in FORTRAN.

If you can't do it in FORTRAN, do it in assembly language. If you can't do it in assembly language, it isn't worth doing.

One of my past jobs was porting an expert system development tool (i.e. AI), written in FORTRAN on PCs under DOS, to Sun, Apollo, Ngen and RS/6000 workstations.
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 
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Offline TERRA Operative

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112222 on: January 25, 2022, 05:35:33 pm »
Thanks.

Doing the relays is quite a job and will cost money... so not sure it's worth it given long term I plan on getting rid of the scope in search of a 784D or 794D....
Will look into it anyway... because it probably will be  a few years before I can afford a 784D...

As for the hybrids I guess you are talking about the die cast box... so you will have to wait until I look into the relays to see what's inside, sorry !  :-[
... but I am sure there must be pics or YT videos about it somewhere....

Or I'll beat you to it if I find a 500 series scope for a good price. :D  :-/O
Where does all this test equipment keep coming from?!?

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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112223 on: January 25, 2022, 05:38:00 pm »
...One of my past jobs was porting an expert system development tool (i.e. AI), written in FORTRAN on PCs under DOS, to Sun, Apollo, Ngen and RS/6000 workstations.

Oh, you poor poor bastard. We didn't know you were a PTSD case; I'll lay off from now on, you've got good reason to be grumpy.  :-DD

mnem
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« Last Edit: January 25, 2022, 05:39:48 pm by mnementh »
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Offline Vince

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #112224 on: January 25, 2022, 05:42:14 pm »
Thanks.

Doing the relays is quite a job and will cost money... so not sure it's worth it given long term I plan on getting rid of the scope in search of a 784D or 794D....
Will look into it anyway... because it probably will be  a few years before I can afford a 784D...

As for the hybrids I guess you are talking about the die cast box... so you will have to wait until I look into the relays to see what's inside, sorry !  :-[
... but I am sure there must be pics or YT videos about it somewhere....

Or I'll beat you to it if I find a 500 series scope for a good price. :D  :-/O

Well given how deep and productive you are with TDS stuff right now... it's indeed by far the most plausible outcome !  :-DD

 


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