Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 14922248 times)

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Offline GerryBags

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9600 on: April 24, 2018, 07:49:07 am »
I’m building a “pyramid of accuracy and resolution” here so these will be subjects to the master once calibrated :D

... both physical and metrological pyramids, I suspect.

The great pyramid scheme of the geezer plateau.
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9601 on: April 24, 2018, 07:49:20 am »
I’m building a “pyramid of accuracy and resolution” here so these will be subjects to the master once calibrated :D

... both physical and metrological pyramids, I suspect.

Yes it’s going to have to be :D
 

Offline Mr. Scram

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9602 on: April 24, 2018, 08:31:34 am »
And what is wrong with a few pages of 50% general PC griping? If we were actively arguing about it, yeah, I could see... but this is just good-natured water-cooler talk, and unlike most such chatter, it didn't devolve into virtual cat-calling or chest-beating. Smeesh. It is EXACTLY the same as the above "Shed talk"; in fact it IS just that. It's just venting; everybody needs to do that, and they need to do it in the company of friends for it to help.

Nice string of "P" words there, though.  :clap: Well-played.  :-+

Oh, FFS... that's like saying talking about water or air is an offshoot of discussion from another thread.  :palm: Ontogeny does NOT recapitulate Phylogeny, no matter how many times you read such in dusty old tomes that were wrong. They were STILL all WRONG.  |O

This subject matter was born here of honest discussion, it belongs here, and getting bent outta shape because you've seen any or all of it in a dozen other threads is really a matter of tuning your personal annoyance filters rather than anything really wrong with the content. If you think that random good-natured venting about OSes should be a  "Third Rail" Godwin's Law type thing, then there's something seriously wrong with the SNR in your own perspective matrix.

Most of the time they just vacillate wildly, mocking you as you try to see the pattern in the random flipping digits. I don't need a machine to mock me; I have two children and a wife to do that. :-DD

mnem
*~ Today's discussion ingredients:
Great grey-green greasy grimy gobs of gopher guts, simulated monkey feet, topped up with chopped up baby parakeet and minced mouse butt all molded into twin patties (With actual MOLD!), then cooked in a reduction of bat guano and dingoes' kidneys and served on a toasted sesame seed bun.~* "Bon Appetit!"
z
There's two people here who see the exact same issue you don't seem to see. That makes the likelihood of a calibration error a lot smaller. ;)
 

Offline ChrisLX200

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9603 on: April 24, 2018, 09:30:14 am »

...

Most of the time they just vacillate wildly, mocking you as you try to see the pattern in the random flipping digits. I don't need a machine to mock me; I have two children and a wife to do that. :-DD


mnem


Well of course it will, so you need to smooth it out with a rolling average - and if the instrument cannot do that intrinsically then connect it to a PC and use software. A 10 second average reading won't vary near so much and it's worth the wait for better data.
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9604 on: April 24, 2018, 10:02:06 am »
3478A arrived. I got the one that was in the picture by the looks...

Checking it out now.
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9605 on: April 24, 2018, 10:09:22 am »
Well that's a good start. My current REF02 ref is checked recorded at 10.00027v

 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9606 on: April 24, 2018, 10:20:34 am »

...

Most of the time they just vacillate wildly, mocking you as you try to see the pattern in the random flipping digits. I don't need a machine to mock me; I have two children and a wife to do that. :-DD


mnem


Well of course it will, so you need to smooth it out with a rolling average - and if the instrument cannot do that intrinsically then connect it to a PC and use software. A 10 second average reading won't vary near so much and it's worth the wait for better data.
You should not have to rely on the use of a PC in order to get accurate readings, that kind of technology should be built into the meter. All to often I see these meters with upto 8 digits where the last least significant digits are constantly scrolling. I have some 4.5 digit meters and the last digit on those scrolls at times but it does so at a much slower pace and is readable. this generally happens when the next (internal) digit down scrolls beyond its mid point and thus forces the visible digit to round off.

Yes I have just secured a 5.5 digit meter and I'm already slightly concerned about it as, unlike my existing meters which can be calibrated manually, the new one is software driven and calibrated and relies on battery backed RAM to retain its calibration data and also means I can no longer calibrate it myself against known values. I have yet to see first hand just how stable the last digits will be, but I do need to have that level of precision so it can scroll all it likes really as it is seldom required to go beyond 2 DP of resolution except in tracking down shorts in PCB's where the last digits will give an indication if I'm getting closer or not the actual point of failure. To be honest this is the real reason for its purchase, is to give me that extra "tool" in my kit if I ever need it.
Who let Murphy in?

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Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9607 on: April 24, 2018, 10:24:36 am »
Well that's a good start. My current REF02 ref is checked recorded at 10.00027v


Well thats a good result as the reading is precisely what you would expect given the last digit of your reference is a 7 so it round the 2 up to a 3 as in your display, so the voltage readings at least appear to be spot on.  :-+

I'll be happy if mine is the same as that when it arrives. It looks to be in fair cosmetic condition as well, so that a bonus.
Who let Murphy in?

Brymen-Fluke-HP-Thurlby-Thander-Tek-Extech-Black Star-GW-Avo-Kyoritsu-Amprobe-ITT-Robin-TTi
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9608 on: April 24, 2018, 10:26:02 am »
Ok working fully and calibration good by the looks. Noticed a few things:

1. Two date codes. 86 and 91. Looks like a repair or mod was done in 91 or just after on the front end. It has cal sticker after that which cover cal up to Jan 2017.
2. RIFAs are looking suspect as hell.
3. This is not the earliest rev. It has newer non-can electrolytics and a TO-220 regulator instead of TO-3. Also still uses transformers instead of opto-isolators
4. Mostly clean. Sticker removal will commence later this week.
5. Looks like the battery was replaced already based on the crappy soldering on it. It's an old Saft battery so this was done before last cal. I will replace this at the weekend.

Nudey bits:

 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9609 on: April 24, 2018, 10:50:06 am »
Very nice indeed, neat layout and only the one 91 date code that I can see so I'm kinda wondering if it might have a bug fix carried by the makers rather than a repair?
Who let Murphy in?

Brymen-Fluke-HP-Thurlby-Thander-Tek-Extech-Black Star-GW-Avo-Kyoritsu-Amprobe-ITT-Robin-TTi
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9610 on: April 24, 2018, 10:53:16 am »
Possibly right with that.

I just ran it against my standard resistors which are nice Dale milspec 0.01% and it's reading the same as my friend's recently calibrated keysight unit.  :-+
 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9611 on: April 24, 2018, 10:55:51 am »
Great, its within calibration then, what a great steal, how does that compare with your Agilent hand held then?
Who let Murphy in?

Brymen-Fluke-HP-Thurlby-Thander-Tek-Extech-Black Star-GW-Avo-Kyoritsu-Amprobe-ITT-Robin-TTi
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9612 on: April 24, 2018, 11:00:28 am »
My U1241C matches it on the mark within the limited resolution of it. That actually has proper traceable cal on the U1241C it as well.

Annoyingly though it does show that my GDM-8341 is quite a bit out (compared to my U1241C and 3478A).

Also I have discovered I need some longer test leads as the current ones I have are too short to run this on the shelf  :palm:
 

Offline BU508A

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9613 on: April 24, 2018, 11:00:57 am »
Either that or it’s going to go down like a ponzi and I’m in the voltnut thread.

Come to the volt-nuts. We have cookies! Err, references.

I'm always mixing up these things.

 ::) ;D
“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 #9614 on: April 24, 2018, 11:07:31 am »
My U1241C matches it on the mark within the limited resolution of it. That actually has proper traceable cal on the U1241C it as well.

Annoyingly though it does show that my GDM-8341 is quite a bit out (compared to my U1241C and 3478A).

Also I have discovered I need some longer test leads as the current ones I have are too short to run this on the shelf  :palm:
How much out is the GDM-8341 then, a couple of digits I personally wouldn't worry too much about, although it is kind of comforting to have all ones meters reading the same which is what I currently have got.

Longer leads is always going to be an issue with a meter mounted high up which of course yours are now, my bench meters sit alongside my monitor so not an issue for me. :popcorn:
Who let Murphy in?

Brymen-Fluke-HP-Thurlby-Thander-Tek-Extech-Black Star-GW-Avo-Kyoritsu-Amprobe-ITT-Robin-TTi
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9615 on: April 24, 2018, 11:10:00 am »
About 3mV on a 10V reference.

But tis 300,000 count vs 50,000 count and lower basic accuracy so you're probably right.
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9616 on: April 24, 2018, 11:34:28 am »
Working out how to replace the battery now. Think I’m going to do the swap off line. I’ll isolate it from mains and then solder a 2xAA cell battery box in series with a Schottky diode to form an or gate and solder it in circuit (no clips!) upstream. Then swap the thing out while it is completely mains isolated. Seems safer and less risky than the people doing it powered up.

Data sheet says 2v is the magic “bye bye” voltage.
 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9617 on: April 24, 2018, 11:36:12 am »
Either that or it’s going to go down like a ponzi and I’m in the voltnut thread.

Come to the volt-nuts. We have cookies! Err, references.

I'm always mixing up these things.

 ::) ;D
Haha, I don't know about bd139 but I'm teetering on the edge right now as I have so many handhelds now to choose from now with,
2 x Fluke 27,
13 x Fluke 25,
1 x Robin 1503,
1 x Proster VC97,
2 x Bside DM08A,
1 x Robin 840,
1 x AVO Model 8,
1 x AVO 1001,
1 x Robin 2608,
1 x TMK 500,
1 x TMK 700

and bench meters,
1 x HP 3466A,
1 x Solartron 7045,
1 x Iso-tech IDM-203,
1 x Kikusui 1502,
1 x Keithley 160,
1 x Fluke 8505A
and a HP 3478A on its way, also a Philips PM 2521 in the queue for a possible repair at some point.

Reluctantly I'm parting with the Fluke 8505A as its just too big for my bench and I'll also be parting with some of Fluke 25's soon.
Who let Murphy in?

Brymen-Fluke-HP-Thurlby-Thander-Tek-Extech-Black Star-GW-Avo-Kyoritsu-Amprobe-ITT-Robin-TTi
 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9618 on: April 24, 2018, 11:44:47 am »
Working out how to replace the battery now. Think I’m going to do the swap off line. I’ll isolate it from mains and then solder a 2xAA cell battery box in series with a Schottky diode to form an or gate and solder it in circuit (no clips!) upstream. Then swap the thing out while it is completely mains isolated. Seems safer and less risky than the people doing it powered up.

Data sheet says 2v is the magic “bye bye” voltage.
In the grand scheme of things, 3mv is neither here or there, nothing is that critical of voltage so I'd live with it quite happily so maybe I'm not quite the voltnut yet.
Yes, that seems like a good idea to do it that although I don't think the diode is required as you doing it switched off so even with the iron tip being grounded there's no possibility of shorting the ram to ground because there is no actual return path to the battery.
Who let Murphy in?

Brymen-Fluke-HP-Thurlby-Thander-Tek-Extech-Black Star-GW-Avo-Kyoritsu-Amprobe-ITT-Robin-TTi
 

Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9619 on: April 24, 2018, 11:48:18 am »
bd139, I know you have a Tek 465 in your collection and I was wondering if you could check something for me....

I have a real basket case 465/DM44 here. Blows mainline fuses immediately. I found a dead short on the +15V supply which I have resolved. It was 2 shorted tants. But it's still blowing fuses. I suspect the -8V bus but not sure. I was wondering if you could check the resistance to ground on the power supply test points. Here's what mine read:

+110V  840 ohms
+55V    840 ohms
+15V    183.3 ohms
-8V       56.7 ohms
+5V      94.8 ohms

Much appreciated  :-+
 
An old gray beard with an attitude.
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9620 on: April 24, 2018, 11:57:33 am »
No probs. Give me a couple of hours and I’ll let you know. I’m in the middle of Tesco doing shopping at the moment :)

Check your primary winding resistance as well. Some of them seem to fail short.
 

Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9621 on: April 24, 2018, 11:59:44 am »
No probs. Give me a couple of hours and I’ll let you know. I’m in the middle of Tesco doing shopping at the moment :)

Check your primary winding resistance as well. Some of them seem to fail short.

No hurry and thanks. This puppy is gonna be a long and ongoing project. Got that feeling. This 465 was not treated well.
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Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9622 on: April 24, 2018, 12:02:45 pm »
Primary winding sounds like a good bet, just using simple ohms law, the -8v bus is drawing around 140ma, which shouldn't blow a fuse
Who let Murphy in?

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Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9623 on: April 24, 2018, 12:11:52 pm »
Primary winding sounds like a good bet, just using simple ohms law, the -8v bus is drawing around 140ma, which shouldn't blow a fuse

I just checked primary winding.....8.0 ohms.
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Offline Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9624 on: April 24, 2018, 12:24:00 pm »
And what is wrong with a few pages of 50% general PC griping? If we were actively arguing about it, yeah, I could see... but this is just good-natured water-cooler talk, and unlike most such chatter, it didn't devolve into virtual cat-calling or chest-beating. Smeesh. It is EXACTLY the same as the above "Shed talk"; in fact it IS just that. It's just venting; everybody needs to do that, and they need to do it in the company of friends for it to help.

Nice string of "P" words there, though.  :clap: Well-played.  :-+

It's just saying "Oh God, do we have to talk about that, again?" which you will hear down the pub. Just as pub conversation here in the UK now comes with an implicit "no brexit" rule there are topics that we've all heard too much about.

Quote

The problem is that it's not a seed that has been planted, but a tree that has grown through various threads and now creeps into this one. Enough is enough, we don't need the same discussion in 14 threads.

Oh, FFS... that's like saying talking about water or air is an offshoot of discussion from another thread.  :palm: Ontogeny does NOT recapitulate Phylogeny, no matter how many times you read such in dusty old tomes that were wrong. They were STILL all WRONG.  |O

This subject matter was born here of honest discussion, it belongs here, and getting bent outta shape because you've seen any or all of it in a dozen other threads is really a matter of tuning your personal annoyance filters rather than anything really wrong with the content. If you think that random good-natured venting about OSes should be a  "Third Rail" Godwin's Law type thing, then there's something seriously wrong with the SNR in your own perspective matrix.


Don't exaggerate lad, nobody's "bent outta shape", except perhaps the guy who's moved on to "smiley punctuation" and all bold sentences or sentential clauses (which is pretty much the WYSIWYG version of "all caps").

All one needs to complete the trifecta would be green ink*:)

To change the topic (slightly), the late, great Bill Hicks - a comedian much loved here in the UK but sadly largely ignored in his native America - coined the phrase "tooth to tattoo ratio", whereby he suggested that you could judge a lot about the sanity, ability to hold rational political views and propensity to violence of a person by counting their remaining natural teeth and comparing it to the number of tattoos they had.

May I suggest an online equivalent, which is the ratio of normal, correct punctuation to smilies, tentatively to be called the "Hick's ratio". You all know what (and who) I mean - there's one antipodean contributor whose electronics contribution is vanishingly small, can be seen in every argument and writes without capital letters, commas, full stops, paragraphs and congenitally can't post a single message without at least two smilies for each sentence, or sentence fragment.


* I don't know how well the green ink phenomenon is known outside the UK, where it's had a fair airing in the popular media over the years. It dates to the time when people would write longhand, real letters to the editors of newspapers.  All newspapers get "letters to the editor" from persistent, often monomaniacal, nutters; it was popularly held that these 'contributors' wrote in all capitals and in green ink. From my time as a journo I can say categorically that this is true. I have opened the post and found letters composed longhand, in all capitals and green ink, filled with rambling, unhinged complaints often completely unrelated to the subject matter of the magazine they were sent to. Moreover, not from one person but several different individuals, and this was on an organ with a mere 80k-100k actual physical circulation.

None of this is to be taken to imply that I think mnementh is unhinged, even if he has named himself after a dragon from a series of fantasy books. I, a man who chose the name of a small, drunken, apricot brandy swilling, warlike cartoon aardvark as his nickname, would be skating on very thin ice.

"Skating away-ay,
Skating away-ay,
Skating away-ay,
On the thin ice of a new day-ay-ay-ayay,
Aya-aya-ayay" - Ian Anderson
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 


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