Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 1730344 times)

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Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29850 on: April 21, 2019, 01:49:26 pm »
@bd139: It is a bit curious that you cannot get this resistor. The value seems to have been used frequently, as I found in my stock 963 Ohms and 9.63kOhms, both with 0.1%. Sadly, not the 96.3 Ohms.
Correction: the first are 953 Ohms.

Yes I thought that was a bit weird but it turns out it's not a standard E-series value apparently. Basically the reason it exists is if you design a 10dB attenuator for a 50 ohm system the ideal value is 96.25 ohms for this resistor, rounded to 96.3 on 1DP. This gives a stupidly good return loss for the attenuator (-120dB in theory). Looks like you can get RN60C in that size but they are out of stock everywhere with weeks lead times and stupid min orders. Boo hiss  :--

On amateur radio stuff, it's not *that* important to get it exactly right usually so the pi network is rounded to 100 ohms parallel and 68 ohms series for 10dB which is close enough. RL is not as good at around -50dB and the attenuator isn't that accurate but it'll do.
The nearest standard 1% values are 95.3 or 97.6 but suspect that these are almost equally hard to locate[emoji848]

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Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29851 on: April 21, 2019, 02:31:07 pm »
Mains filter units have overnight moved to local UPS depot and they should be in my hands Tuesday. [emoji4]

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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29852 on: April 21, 2019, 03:35:06 pm »
So this weekend I started thinking about repairing the Keithley 610CR (https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg2257572/#msg2257572) and I was wondering if I would have to change the crude line filter.

I decided to do a little benchmark of different EMI line filters I have laying around, just to compare.

The setup was pretty simple, analysing differential mode (line to line), sweeping from 1Khz to 1Mhz. The idea was to observe the effectiveness of the low pass filter.

1- Canny Well CW1D-10A (cheap emi filter from china)         2- Delta 06GEEG3E         3- Schaffner FN372-2-31         4- Keithley 610CR line filter         

I was surprised. Was expecting to change the Keithley filter but it seem to be working pretty well. I guess they knew what they were doing back then. I'm probably not going to touch it, will just make things worst  :)

Agreed. I like stuff like this; where you can see the guts of it with the naked eye. The only reason I'd change anything in there would be if one of those ancient carbon resistors had shifted value or if there were any visible evidence of overheating damage.

Well... not exactly never... I MIGHT add a modern filter in line with that; since it has no common-mode rejection I'd at least want a common-mode choke and something to tank out the higher uwave frequencies that 6dB filter would let pass.

I realize that given the analog movement, those frequencies probably will not affect the instrument itself, but I'm thinking about noise it might introduce into the DUT, especially if you're testing with this and a scope or other gear at the same time.   :-BROKE

When this thing was made, they never envisioned the realities of our modern RFI/EMI hostile world; we mortal humans live and breathe and work engulfed in a blanket of radiation from UHF to multi-GHz frequencies that would've given physicists of the time the screaming heebie-jeebies.  :scared:

mnem
*Eternally seeking the resonant frequency of the Cosmic String*
 

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29853 on: April 21, 2019, 05:38:34 pm »
I keep seeing something else but then maybe my mind just a little more warped than others  :-DD

Handle Mark II added circuit board slots for a 20x80x1.6 PCB for alternate versions.

THREAD CREATED https://www.eevblog.com/forum/projects/open-hv-probe/msg2357637/#msg2357637

No, not at all. I just have my "parental filter" still engaged due to recent "Easter Get-together" time with the GPs and GGPs. Have no fear; I'm still as pervy as ever.  >:D

Thread noted, perused and inappropriate comments made.  :-DD

Cheers, and Happy Spring Equinox!!!

mnem
 
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Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29854 on: April 21, 2019, 05:45:18 pm »
Hahahaha that had me in tears. Being Easter, my tradition is getting pissed so I'm a bottle of red and several Abbots' in now.

Happy Easter indeed  8)
 

Online Ero-Shan

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29855 on: April 21, 2019, 06:36:42 pm »
Just when you thought you'd got rid of me ... well, I'm still alive and still acquiring TE every now and then - but it gets harder each day finding something on the bay, at least at a decent price.

Since there's no known upper limit to the number of counters that one can have, I decided to get me another :


With HP and Nixies, you can't go wrong, can you? >:D
 
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Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29856 on: April 21, 2019, 06:40:23 pm »
Ooh sexy. Nice one  :-+
 

Online Ero-Shan

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29857 on: April 21, 2019, 06:57:43 pm »
And while I'm at it ...

I finally bit the bullet and got me an SA. Quite pricey compared to my average TE spending, but still cheaper than a new one. The input termination is switchable between 50 Ω and 75 Ω - the latter is useful for TV.



One more hole plugged.
 
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Offline kj7e

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29858 on: April 21, 2019, 08:08:14 pm »
You know you need to have one now.

https://youtu.be/ly6b49ZyaRg
 
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Offline wch

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29859 on: April 21, 2019, 08:43:06 pm »
You know you need to have one now.

https://youtu.be/ly6b49ZyaRg

arrghhh... i hate you! i've been wandering around for the last six days looking for a bargain 53310A, have a e-stack of manuals, and a saved ebay search. do i need one? of course not! but i didn't need the TDS420A and that's in my basement, next to my bench this morning, too (that's another story...)   |O

hey, i have an idea!  wanna trade one of yours for an oscilloscope? i have a lot of oscilloscopes right now.     ;D
proceed until apprehended
 

Offline kj7e

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29860 on: April 21, 2019, 08:56:42 pm »

hey, i have an idea!  wanna trade one of yours for an oscilloscope? i have a lot of oscilloscopes right now.     ;D


No.  ;D
 

Offline wch

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29861 on: April 21, 2019, 09:01:53 pm »

hey, i have an idea!  wanna trade one of yours for an oscilloscope? i have a lot of oscilloscopes right now.     ;D


No.  ;D

 :(

Somehow I knew that was what you would say....   ;D
proceed until apprehended
 

Online bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29862 on: April 21, 2019, 09:09:29 pm »
Ok the previously mentioned alcohol has worn off and I’m craving an HP counter now  :-DD
 

Offline Kosmic

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29863 on: April 22, 2019, 01:31:47 am »
am curious about what you used to make those phase/gain plots. 

have an aim 4170 but it is only a one port unit good for S11 (and it maybe it is recommended only for use above 100Khz?)

have been thinking about picking up a digilent analog discovery for  S21 but have never had one in hand to see how it performs.

your sweeps look great!

I used my cheap Adalm2000. It's similar to the Analog Discovery 2 but cheaper (and apparently less performant). The software take care of all the plots and you can export the data in .csv file if you want.

https://wiki.analog.com/university/tools/m2k/scopy/networkanalyzer
 
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Online beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29864 on: April 22, 2019, 01:35:32 am »
I keep seeing something else but then maybe my mind just a little more warped than others  :-DD

Handle Mark II added circuit board slots for a 20x80x1.6 PCB for alternate versions.

THREAD CREATED https://www.eevblog.com/forum/projects/open-hv-probe/msg2357637/#msg2357637

No, not at all. I just have my "parental filter" still engaged due to recent "Easter Get-together" time with the GPs and GGPs. Have no fear; I'm still as pervy as ever.  >:D

Thread noted, perused and inappropriate comments made.  :-DD

Cheers, and Happy Spring Equinox!!!

mnem


The only good thing about this revolving date pagan event is the reduced guilt of buying and eating Chocolate  ;D
Coffee, Food, R/C and electronics nerd in no particular order :)
 
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Offline Kosmic

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29865 on: April 22, 2019, 02:12:13 am »
Well... not exactly never... I MIGHT add a modern filter in line with that; since it has no common-mode rejection I'd at least want a common-mode choke and something to tank out the higher uwave frequencies that 6dB filter would let pass.

Good point. There's 2 ceramic cap between Hot - Gnd and Neutral - Gnd to help with common mode but it's probably not enough.
 

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29866 on: April 22, 2019, 02:41:55 am »
I NEVER have guilt about eating chocolate; especially if I'm on my low-carb diet. If I eat enough to break the diet, when it comes time for the metabolism shift I feel like shit for a day or two, so  I'm paying for it. I refuse to have guilt over a misdeed paid for. If I make a successful guerilla attack on my chocolate stash... one small and swift enough that I don't eff up the ketosis... then I have nothing to be guilty over anyways.  :-+

Besides... my favorite kind... 70% or more dark chocolate... is actually on my diet as long as I count the few carbs it has. And it's good for your heart.  :-+

mnem
Chocolate is love.

 

Offline 0culus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29867 on: April 22, 2019, 02:49:30 am »
Dark chocolate is good for you. :D
 

Online beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29868 on: April 22, 2019, 02:59:43 am »
My Dark Chocolate Stash sits in the Bedside Drawer for casual consumption and Milk Chocolate or worse Faked Chemical Chocolate has no place in my internals.
Coffee, Food, R/C and electronics nerd in no particular order :)
 
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29869 on: April 22, 2019, 03:05:57 am »
Oh, I have a weakness for Reese's Peanut butter cups... especially the giant novelty ones as I like the balance of chocolate to peanut butter fudge better. But generally I prefer dark chocolate to milk chocolate. Was tickled pink at the resurgence of M&M/Mars MOUNDS candy bars as well. Love dark chocolate and coconut.  :-+

mnem
*Nutty*
 
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Offline kj7e

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29870 on: April 22, 2019, 03:13:23 am »
 

Offline bitseeker

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29871 on: April 22, 2019, 03:52:40 am »
Good grief HP Nixie counters are still fetching big money. HP 5221B closed at $101.50 plus shipping. :o
I TEA.
 

Offline bitseeker

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29872 on: April 22, 2019, 03:54:35 am »
You know you need to have one now.

https://youtu.be/ly6b49ZyaRg

I already knew I wanted one when you first introduced it. But, that's OK. You can keep torturing me with good info. I can take it. :-DD
I TEA.
 

Offline bitseeker

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29873 on: April 22, 2019, 04:51:34 am »
Just when you thought you'd got rid of me ... well, I'm still alive and still acquiring TE every now and then - but it gets harder each day finding something on the bay, at least at a decent price.

Since there's no known upper limit to the number of counters that one can have, I decided to get me another :


With HP and Nixies, you can't go wrong, can you? >:D

Nope, can't go wrong with that. Nice B model. I have an A (no DMM).

In other Nixie news, I picked up a Keithley 160 today. Here it is (middle instrument) measuring 10V out from an HP 6114A precision power supply. My Keysight U1282A reports the output as 10.009V. Nothing's been warmed up in advance. I just turned it on to see it all run, but it hasn't changed since it was cold about 20 minutes ago. Good stuff. Just needs a little adjustment.
I TEA.
 
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Online Ero-Shan

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #29874 on: April 22, 2019, 06:21:05 am »

In other Nixie news, I picked up a Keithley 160 today. Here it is (middle instrument) measuring 10V out from an HP 6114A precision power supply. My Keysight U1282A reports the output as 10.009V. Nothing's been warmed up in advance. I just turned it on to see it all run, but it hasn't changed since it was cold about 20 minutes ago. Good stuff. Just needs a little adjustment.

Nice! The Keithley appears somewhat red on the photo. There's no need for it to feel embarrassed that I can see, though. ;)
 


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