Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 2874705 times)

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Offline Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47575 on: January 21, 2020, 11:14:14 pm »
Normal knob is fine. You only need the vernier type knobs if you want it to be direct reading like a pot with an indicator dial.

Edited to add: Didn't spot the 2nd bit. A vernier knob will turn through 3600 degrees (give or take) so if you stuck it on a standard 270 degree pot it wouldn't even use 10% of it's travel.
« Last Edit: January 21, 2020, 11:16:10 pm by Cerebus »
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 
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Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47576 on: January 21, 2020, 11:33:30 pm »
A few days ago there much discussion about removing SME's safely and Paul Carlson recommended twisting them off but others said that risked tearing the pads of the board. Well I was flicking through YT as you do when lost for something to do  :-DD and came this video, which seems to work very well, in fact IIRC someone did mention this method, but I thought this video might add a bit of substance to the words.

Who let Murphy in?

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Offline WastelandTek

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47577 on: January 21, 2020, 11:34:07 pm »
Goal reached !

TDS540 run after eletrolytics  mass replacing and  swapped CTL IC (Tek special ic), but  few  error message stays.

three SRAM is dead, replaced -> no error message.

Greetings
matt

impressive

well done!
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Online beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47578 on: January 22, 2020, 12:14:55 am »
New box of TEA making goodies in the mail today. If you have to ask how much they cost go buy an old 6 1/2 digit meter instead and buy booze with the change ;)

Reading a few PPM higher than Edwins Calibration report (still within the 0.005%) but it has already gone to the high side of 30C so it might be a short day in the shack :phew:

Couple of LTZ1000 sets and a stack to make a Hamon Divider.
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Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47579 on: January 22, 2020, 12:24:40 am »
Assuming the 34461A is dead nuts then the resistors are only just within spec but I suspect that it is a bit of the meter and the resistor here?
Who let Murphy in?

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Offline worsthorse

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47580 on: January 22, 2020, 12:36:17 am »
I love the look of this, do you have a model number?

Also I have found that it's always nice to do battery replacement with the property batteries.  I've had to do this with all of the analog miniature scopes I have.  I've found that it's nice to use the proper batteries and the built in charging circuit.  I was able to NiCd batteries with tabs from amazon for my tek 323.  I had my NLS MS-15 ruining on Li Ion batteries, but it was annoying to charge and the LDO I put in produced more heat then I'd like.  I could have fixed that putting in a switching regulator and better charging circuitry, but in the end I found that an emergency lighting LDO was a drop in replacement.


They are from my newly acquired Time Current Calibrator; look at the minimum scale and resolution, but the spec is +-0.2nA etc :)


Nice acquisition. Twinges of jealousy here as I've been trying to find a current calibrator I can afford for a while!
bark less, wag more.
 

Online beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47581 on: January 22, 2020, 12:44:21 am »
Assuming the 34461A is dead nuts then the resistors are only just within spec but I suspect that it is a bit of the meter and the resistor here?

The one on test was according to the Cal from Edwin 12PPM high @19C and I know the 34461A trends high when hot so there won't be a lot in it when it cools off. Just interesting to spot check my meter against his better gear.

Quote
Temperature: 19.05°C

Uncertainty: ≤0.5 PPM


Primary Standard: ESI SR-104, Deviation: +2.67 PPM, Uncertainty 0.15 PPM, TCR: 0 PPM/°C

Primary bridge: ESI 242D

Readings valid at the time of calibration, subsequent readings may vary due to changes in conditions and time.
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Offline Kosmic

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47582 on: January 22, 2020, 01:29:34 am »
New box of TEA making goodies in the mail today. If you have to ask how much they cost go buy an old 6 1/2 digit meter instead and buy booze with the change ;)

Reading a few PPM higher than Edwins Calibration report (still within the 0.005%) but it has already gone to the high side of 30C so it might be a short day in the shack :phew:

Couple of LTZ1000 sets and a stack to make a Hamon Divider.

Looking good  :-+ I need to find a project to justify buying some nice resistors from Edwin.
 

Offline Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47583 on: January 22, 2020, 02:10:26 am »
A few days ago there much discussion about removing SME's safely and Paul Carlson recommended twisting them off but others said that risked tearing the pads of the board. Well I was flicking through YT as you do when lost for something to do  :-DD and came this video, which seems to work very well, in fact IIRC someone did mention this method, but I thought this video might add a bit of substance to the words.



A description for those who can't be arsed to skip around the video to find the meat of it.

This guy cuts the can off with sidecutters, as close to the circuit board as he can get. Then he cuts the base of the capacitor in half, leaving single pads to be desoldered. Often, with a bit of picking debris off with his fingernails,  this seems to just leave a 'nub' of lead behind on the pad which could pretty much be wiped off the board with your iron's tip.

Well it could be casually wiped off by those of us in Metcal land, your mileage may vary.  :)

Neat, it looks as if it could work well. Next time I've got the 'soldering box' out and on the table I'll grab a scrap board and give it a try.
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47584 on: January 22, 2020, 05:41:54 am »
Yes, this is precisely the technique I recommended ages ago when we first talked about "Carlson's Great Capacitor Sin Video". Why the fuck does nobody ever listen...? :palm:

mnem
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47585 on: January 22, 2020, 05:56:00 am »
In Other News...

Just picked up a Android TV Box based on price vs "features"; found it was an unusable clusterfuck of crashing apps and "Google Play Doesn't love Me No More"  BS :bullshit: brand new out of the box.  :palm: Looking for recommendation on one that is NOT a complete POS; I need Stereo Analog & Optical audio out. Currently considering a Roku Express+ with Analog Audio but no optical for approx $US 60 new.

Thanks,

mnem
 |O
 

Offline AVGresponding

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47586 on: January 22, 2020, 06:12:49 am »
On a scale of "ugh" to "aargh!", how unobtainium are parts for VFD repairs on 34401A's?

There's one for pennies with a knackered display on fleabay atm
nuqDaq yuch Dapol?
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Online beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47587 on: January 22, 2020, 06:19:33 am »
There is any number of the actual VFD's available on Evilbay ex China. I have never looked but I would think the circuit diagram should be available too.
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Offline Zucca

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47588 on: January 22, 2020, 07:15:24 am »
On a scale of "ugh" to "aargh!", how unobtainium are parts for VFD repairs on 34401A's?

There's one for pennies with a knackered display on fleabay atm


There is a qu1ck solution:

https://www.eevblog.com/forum/repair/hp-34401a-dmm-with-leaking-segments/

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Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47589 on: January 22, 2020, 08:08:53 am »
You can still buy new VFD modules from keysight spares. They’re £121 + VAT a go: https://www.keysight.com/my/partDetail/34401-66522
« Last Edit: January 22, 2020, 08:10:53 am by bd139 »
 
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Online beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47590 on: January 22, 2020, 08:52:33 am »
Sometime later and a much nicer 18C and back down a touch toward Edwins numbers. I wonder if a few of the PPM high might be the cheap and cheerful 4W clips over a quality alternate?

Coffee, Food, R/C and electronics nerd in no particular order. Also CNC wannabe, 3D printer and Laser Cutter Junkie and just don't mention my TEA addiction....
 

Offline tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47591 on: January 22, 2020, 09:29:19 am »
I love the look of this, do you have a model number?

Also I have found that it's always nice to do battery replacement with the property batteries.  I've had to do this with all of the analog miniature scopes I have.  I've found that it's nice to use the proper batteries and the built in charging circuit.  I was able to NiCd batteries with tabs from amazon for my tek 323.  I had my NLS MS-15 ruining on Li Ion batteries, but it was annoying to charge and the LDO I put in produced more heat then I'd like.  I could have fixed that putting in a switching regulator and better charging circuitry, but in the end I found that an emergency lighting LDO was a drop in replacement.


They are from my newly acquired Time Current Calibrator; look at the minimum scale and resolution, but the spec is +-0.2nA etc :)


Nice acquisition. Twinges of jealousy here as I've been trying to find a current calibrator I can afford for a while!

It came with a Fluke 515 which is pretty much dead on e.g. the 10V is 20ppm high, except the 10Mohm resistor is "noisy". Also a Keithley 230 programmable voltage source, which I might decide to flip.
There are lies, damned lies, statistics - and ADC/DAC specs.
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Offline tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47592 on: January 22, 2020, 09:32:32 am »
A description for those who can't be arsed to skip around the video to find the meat of it.

Thank you.

Most videos consume too much of my little remaining life, so I can't be arsed to watch them unless I know it contains worthwhile and moving pictures.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
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Online Cubdriver

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47593 on: January 22, 2020, 09:37:45 am »
A description for those who can't be arsed to skip around the video to find the meat of it.

Thank you.

Most videos consume too much of my little remaining life, so I can't be arsed to watch them unless I know it contains worthwhile and moving pictures.

Yeah, I watched that one at 2x speed and it still took too long to get to the point.

-Pat
If it jams, force it.  If it breaks, you needed a new one anyway...
 

Online VK5RC

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47594 on: January 22, 2020, 10:04:51 am »
My initial experience in volt-nut land, found EMI was a significant problem, I would try doing things like switching everything thing you can off (if you haven't tried this) and see what happens. My laptop (Toshiba) was about 50uV difference. The 34461 I have found usually good for 5-10ppm, even though rated 35ppm/yr.
I recall Edwin uses some bridging type arrangement for his resistance measurement - do you recall the details?
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Online beanflying

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47595 on: January 22, 2020, 10:19:48 am »
He uses one of these ESI 242D https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=ESI+242D&_sacat=0 I won't be adding one to the collection  ::) Details are above in an post from this morning.

I have been going through all the gear in the shack and removing the noticeable offenders. The last one was a simple LED wallwart that was upsetting the Fluke Calibrator at over 1.5m  :-- Off to on was a definite and measurable few PPM.

If I am being careful then PC's and monitors off along with the Coffee machine and the Cal gear is on the back rack with only one mains lead into it. Apart from that I could re arrange and run it off the  decent sized UPS I have but that is another possible source I guess.

Re the 34461A I rate the 34401A I have as more stable.
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Online BU508A

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47596 on: January 22, 2020, 10:38:10 am »
On a scale of "ugh" to "aargh!", how unobtainium are parts for VFD repairs on 34401A's?

There's one for pennies with a knackered display on fleabay atm


Depends, on what you have to repair. If you have an early version of these displays, they are built with unobtainium driver ICs.

Also note that the early 34401A (panel assembly 34401-66502) have unobtanium VFD driver ICs and cannot be replaced by the newer assembly due to firmware incompatibility, which is another reason to get the later units (firmware 06-04-02 or higher), if you buy another.

On the other hand, the VFD itself is the same for both assemblies and new VFDs are available from China, which is a nice benefit of having a 34401A vs. some other model.

Here is a nice repair documentation made by TiN:
https://xdevs.com/fix/hp34401a/

And here is a nice project on how to replace the display with an OLED display:
https://github.com/openscopeproject/HP34401a-OLED-FW
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Online VK5RC

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47597 on: January 22, 2020, 10:42:39 am »
I should pull my finger out and publish some of the long term results with the ltzs. Honestly I think that quite a bit of it comes down to luck - did you get a good ltz and just the right resistor combo for it. I have multiple combinations of pcbs, op amps, resistors and ltz, I think about 70% suck (10+ppm overall true accuracy over the long term - including the box, pcb, reasonable room temp etc) , the others pretty good ie within 2-4ppm long term - as far as I can tell. Looking at all of the references - the 3458 itself looks pretty good - it is an old unit - and I think HP got first dibs on the ltzs and cherry picked the better ones.
I have only had the 3458 calibrated once and it did not seem to like the travel! All its measurements of most of my ltzs were out by 1-2ppm for a month or so after it returned then settled back to pre-cal. It was within spec and no adjustments.
Unfortunately the unit that TiN calibrated for me was not one of the better units.
Whoah! Watch where that landed we might need it later.
 

Offline madao

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47598 on: January 22, 2020, 10:45:44 am »
Yes, this is precisely the technique I recommended ages ago when we first talked about "Carlson's Great Capacitor Sin Video". Why the fuck does nobody ever listen...? :palm:

mnem
 :horse:

It is not your and my beers, if someone rips solder pad, after watching of carlson lab video.. :-//

My solution by case with minor capitor plague.
Two solder iron!


 
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Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #47599 on: January 22, 2020, 10:54:35 am »
Yes, this is precisely the technique I recommended ages ago when we first talked about "Carlson's Great Capacitor Sin Video". Why the fuck does nobody ever listen...? :palm:

mnem
 :horse:
Oi, I did, just couldn't remember who, hence why I said IIRC  :-DD :-DD :-DD
Who let Murphy in?

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