Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 18796541 times)

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Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9650 on: April 24, 2018, 05:55:48 pm »
Anyway, lets not dwell on this subject any longer and draw a line in the sand and move on.

I think, I hope, that you mean "draw a line under it". Drawing a "line in the sand" normally means, "There's the line, you cross it, you get it (in the face/guts/whatever)".
Yes, I did mean draw a line under it  :-+
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Offline BravoV

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Heathkit Model V-7 A Vacuum Tube Voltmeter
« Reply #9651 on: April 24, 2018, 05:57:23 pm »
Ok, back to true TEA .. (blame Cerebus on the highlight :P) .. and please stop the arguing among TEA brethren.

A freebie meter from friend just now, and also my 1st vacum tube test equipment.  :scared:

Still don't know what to do with it.
« Last Edit: April 24, 2018, 06:06:17 pm by BravoV »
 

Offline GerryBags

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9652 on: April 24, 2018, 06:01:20 pm »
We all just need to just draw a line in the sand under the water under the bridge..... ???
 

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9653 on: April 24, 2018, 06:06:06 pm »
Hmm, I know well of what you speak here young sir, my son is a moderator and co-owner of an aviation forum website and people will polarise themselves one way or another, and for the record and benefit of all the other parties involved, I'm not taking sides or showing any favouritism by commenting here.

The trick with moderating as I see it is really one of ensuring that nothing gets out of hand by offensive and flaming takes over, we are all individuals and have our own opinions and it is the airing of those opinions that help understand each others points of view.  We are, are we not all adults here and as such should respect each others view point and cut each other some slack?

Its my view that this topic about OS's is getting way out of hand and has been prolonged far longer then it would have done if objections to what was in effect very much related to the core subject of TEA, had not been raised in the first instance but we all have off days and react in a fashion that normally we wouldn't.

As to the use of bold or even capitals in a written message be it a letter or an email, then it very much depends on the amount used. If all the message in capitals, then yes it is considered to be shouting, but a few words here or there is not, it is considered as a way of emphasising something. This I know because I had to take legal advice with regard to an email I sent to a company director who had a thing about email etiquette. I used a few capitals for emphasis only and he took it personally that I was shouting at him and that in his view was not a proper way to communicate with a director. It was perfectly fine for him to draw certain assumptions about some actions that I was deemed to have done incorrectly etc and speak down to me and even used IIRC a few capitals but not the other way around. Anyway, the legal position is that the use of capitals, bold or italics as I had used them was a perfectly acceptable fashion of re-enforcing a point and that I was perfectly entitled to use them as a robust defense of myself.  In my defense at the time that I received the email from the director, I had also that day received some very disturbing personal news and and my normal more rational side was suppressed by the news I had received so I reacted without thinking it through properly.

Another situation I got myself into hot water with the MD over my use of the word "pro-rata" in an email, meaning proportional but the MD had other ideas as to what it meant and rather then finding out its true meaning, took it out on me, without even giving me the courtesy of explaining what I meant, he was judge and jury and I was guilty as charged in his view  :palm:

Anyway, lets not dwell on this subject any longer and draw a line in the sand and move on.

Agreed, and I agree with the "Everything in moderation, especially moderation." model of moderating. Until it turns flame-ey or ridiculously recursive (a little recursion can be amusing; I for one LOVE a good running gag) I keep hands off, then politely but firmly apply the brakes, then the time-out chair, then the ban-hammer in that order. That approach has never failed me.

I think the main problem here, and one that is almost impossible to eliminate, is honest disagreement over where the "ridiculous" line lies. That, IMO, is precisely why we need moderation, and as long as the mods are reasonable and willing to hear civilized debate over those lines (provided it is KEPT civil, of course) then a forum is and will remain a successful, living entity. Otherwise we'd just be Face/Butt, where most of the moderation is done by bots.

Over here, we say "Stick a pin in it", but I think you mean the same thing, and I agree. Time to move forward.

mnem
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« Last Edit: April 24, 2018, 06:08:11 pm by mnementh »
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Offline bd139

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Re: Heathkit Model V-7 A Vacuum Tube Voltmeter
« Reply #9654 on: April 24, 2018, 06:07:42 pm »
Ok, back to true TEA .. (blame Cerebus on the highlight :P) .. and please stop the arguing among TEA brethren.

A freebie meter from friend just now, and also my 1st vacum tube test equipment.  :scared:

Still don't know what to do with it.

Good meters. Pretty RF immune and fun to use! Replace the selenium rectifier if it has one or it’ll stink the place out suddenly.
 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9655 on: April 24, 2018, 06:09:22 pm »
Ok, back to true TEA .. (blame Cerebus on the highlight :P) .. and please stop the arguing among TEA brethren.

A freebie meter from friend just now, and also my 1st vacum tube test equipment.  :scared:

Still don't know what to do with it.
They are nice meters but with better meters available today for volts and resistance measuring, they are better used in my view for the alignment of AM broadcast radios using the centre zero range of the meter as it provides an excellent indication of when the IF's are perfectly set to a peak.

That's what I use mine for, but back in the day they were among the most accurate meters around thanks to their input impedance providing minimal loading on the circuit under test.
Who let Murphy in?

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Offline Cerebus

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Re: Heathkit Model V-7 A Vacuum Tube Voltmeter
« Reply #9656 on: April 24, 2018, 06:10:43 pm »
Ok, back to true TEA .. (blame Cerebus on the highlight :P)

Be careful, a little known feature is that one can unleash \$ \LaTeX \$ on here. Once that starts in earnest we're all on the road to hell ...
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 

Offline BravoV

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Re: Heathkit Model V-7 A Vacuum Tube Voltmeter
« Reply #9657 on: April 24, 2018, 06:11:56 pm »
Good meters. Pretty RF immune and fun to use! Replace the selenium rectifier if it has one or it’ll stink the place out suddenly.

Oh, thanks for the warning, btw how does it looks, I will do teardown photos or even restoration thread for it if time allowed

Hmm .. this is also my 1st selenium rectifier in the house.

Offline mnementh

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Re: Heathkit Model V-7 A Vacuum Tube Voltmeter
« Reply #9658 on: April 24, 2018, 06:13:53 pm »
Ok, back to true TEA .. (blame Cerebus on the highlight :P) .. and please stop the arguing among TEA brethren.

A freebie meter from friend just now, and also my 1st vacum tube test equipment.  :scared:

Still don't know what to do with it.

Good meters. Pretty RF immune and fun to use! Replace the selenium rectifier if it has one or it’ll stink the place out suddenly.

OMG! Just reading that and I can SMELL the first selenium meltdown I ever experienced as a teen; from an old car battery charger when I forgot to unhook it before cranking the engine over. And I happened to be leaning right over of it when it smoke-bombed...


mnem
*Koff... koff... kakkk... gag... koff... hork up half a lung.. kofff*
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Offline Specmaster

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Re: Heathkit Model V-7 A Vacuum Tube Voltmeter
« Reply #9659 on: April 24, 2018, 06:16:54 pm »
Ok, back to true TEA .. (blame Cerebus on the highlight :P) .. and please stop the arguing among TEA brethren.

A freebie meter from friend just now, and also my 1st vacum tube test equipment.  :scared:

Still don't know what to do with it.

Good meters. Pretty RF immune and fun to use! Replace the selenium rectifier if it has one or it’ll stink the place out suddenly.
This is a valid, not that I have experienced it but I've heard about. Another thing to look out for is the battery terminals corroding and also of course that you must use the jack plug with a 1M resistor in series with the probe when measuring DC volts.
Who let Murphy in?

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

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Re: Heathkit Model V-7 A Vacuum Tube Voltmeter
« Reply #9660 on: April 24, 2018, 06:20:18 pm »
Ok, back to true TEA .. (blame Cerebus on the highlight :P) .. and please stop the arguing among TEA brethren.

A freebie meter from friend just now, and also my 1st vacum tube test equipment.  :scared:

Still don't know what to do with it.

Good meters. Pretty RF immune and fun to use! Replace the selenium rectifier if it has one or it’ll stink the place out suddenly.

OMG! Just reading that and I can SMELL the first selenium meltdown I ever experienced as a teen; from an old car battery charger when I forgot to unhook it before cranking the engine over. And I happened to be leaning right over of it when it smoke-bombed...


mnem
*Koff... koff... kakkk... gag... koff... hork up half a lung.. kofff*
Nope never had that happen to me, but I did have a battery explode in my face when I accidentally moved a croc clip when it was charging, I was jolly glad that night that I was not the only person working the late shift, thats for sure.
Who let Murphy in?

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Offline BravoV

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Re: Heathkit Model V-7 A Vacuum Tube Voltmeter
« Reply #9661 on: April 24, 2018, 06:25:44 pm »
.... and also of course that you must use the jack plug with a 1M resistor in series with the probe when measuring DC volts.

Wow, noted, thanks.

Offline Specmaster

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Re: Heathkit Model V-7 A Vacuum Tube Voltmeter
« Reply #9662 on: April 24, 2018, 06:30:23 pm »
Good meters. Pretty RF immune and fun to use! Replace the selenium rectifier if it has one or it’ll stink the place out suddenly.

Oh, thanks for the warning, btw how does it looks, I will do teardown photos or even restoration thread for it if time allowed

Hmm .. this is also my 1st selenium rectifier in the house.
Of course there's every possibility that the selenium rectifier has already been replaced given its age.
Who let Murphy in?

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

Offline Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9663 on: April 24, 2018, 06:33:37 pm »
I've experienced burning selenium rectifier and I've experienced burning RIFA X class capacitors and I can't quite decide which is worse.

Funny element selenium. Essential to mammals in tidy quantities, toxic at 400 µg a day in humans. Intensive agriculture depletes soil selenium levels which aren't replenished. If you eat food grown exclusively in some areas you can suffer selenium deficiency, the signs of which are subtle and hard to diagnose.
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 

Offline Specmaster

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Re: Heathkit Model V-7 A Vacuum Tube Voltmeter
« Reply #9664 on: April 24, 2018, 06:40:07 pm »
.... and also of course that you must use the jack plug with a 1M resistor in series with the probe when measuring DC volts.

Wow, noted, thanks.
If you don't have a manual then you can download one here and also a schematic. https://www.mods.dk/manual.php?brand=heathkit
Who let Murphy in?

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Offline GerryBags

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9665 on: April 24, 2018, 06:47:00 pm »
I've experienced burning selenium rectifier and I've experienced burning RIFA X class capacitors and I can't quite decide which is worse.

Funny element selenium. Essential to mammals in tidy quantities, toxic at 400 µg a day in humans. Intensive agriculture depletes soil selenium levels which aren't replenished. If you eat food grown exclusively in some areas you can suffer selenium deficiency, the signs of which are subtle and hard to diagnose.

Brazil nuts, apparently, are still a good source of dietary selenium. I think they're only quasi-cultivated and still need unfarmed rainforest soil.

As for Rifa madness, I've experienced X-class Rifa smoke (usual 24XX emi filter caps), significantly worse than Disque-Bleu and ALMOST as bad as the cheap Russian cigarettes my brother got saddled with many moons ago... redolent of toasted teenager's socks. I actually didn't find the Rifa-smoke as objectionable (Many people who know me would choke on their beer if they heard that rather than read it) as the 220uF electrolytic I stupidly reversed on a breadboard a couple of weeks ago. Stinky and lingering.

I have an ancient Marconi RC oscillator which has a big rectifier that I fear may be selenium. That one is going to have to be fired up near an openable window once fixed, I think.
 

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9666 on: April 24, 2018, 08:12:49 pm »
This brings to mind a question that has niggled at me for a while since I've been out of the trade for a long time.

Are these caps any better designed since the line was taken over by Kemet, or are even the newer product also just a ticking smoke-bomb waiting for a place to happen?

mnem
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Offline GerryBags

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9667 on: April 24, 2018, 08:34:03 pm »
This brings to mind a question that has niggled at me for a while since I've been out of the trade for a long time.

Are these caps any better designed since the line was taken over by Kemet, or are even the newer product also just a ticking smoke-bomb waiting for a place to happen?

mnem
*On-topic-ily*

What is it that finally kills them? Anybody know? I know that when mine popped it was a day after the 'scope had arrived at mine after a 2 day journey in cold temps across country. Perhaps thermal shock finished it off, but the other Rifa cap on the A2 board was also bulging and cracking it's plastic case without having popped yet.
 

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9668 on: April 24, 2018, 08:48:49 pm »
This brings to mind a question that has niggled at me for a while since I've been out of the trade for a long time.

Are these caps any better designed since the line was taken over by Kemet, or are even the newer product also just a ticking smoke-bomb waiting for a place to happen?

mnem
*On-topic-ily*
What is it that finally kills them? Anybody know? I know that when mine popped it was a day after the 'scope had arrived at mine after a 2 day journey in cold temps across country. Perhaps thermal shock finished it off, but the other Rifa cap on the A2 board was also bulging and cracking it's plastic case without having popped yet.
IME it's been they've been powered down for a bit and moisture ingress while so.
If the cap is not across a low impedance supply like mains they won't fail so spectacularly.
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Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9669 on: April 24, 2018, 09:16:30 pm »
I think they’re just wankers.

I’ve had four go on me. Most surprising was a Henry hoover.
 
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Offline Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9670 on: April 24, 2018, 09:22:47 pm »
IME it's been they've been powered down for a bit and moisture ingress while so.
If the cap is not across a low impedance supply like mains they won't fail so spectacularly.

The consensus seems to be moisture ingress due to degradation in the case. This seems to show up worst in capacitors that have been under electrical and thermal stress for a long time, and then are given a rest before being stressed again. Almost exactly the circumstances that one would expect from test equipment that has been under daily, or possibly even continuous, use for years, gets taken out of service, stored on a shelf for a few months and then suddenly powered up again in some TEA addicts living room or lab. The crucial promoter of failure seems to be that \$ x \$ month rest on a shelf.

I suspect that if they were gradually re-introduced to power by, say, inching up a variac over a week, then they might dry out and survive. Who, however, is going to wait a week to try out some new bit of kit, plus you'd be a-feared of them spouting flame on day three while you slept.
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 #9671 on: April 24, 2018, 09:23:34 pm »
So mechanical failure of the envelope is the mechanism rather than electro-thermal breakdown?

Hmmmm...

mnem
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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9672 on: April 24, 2018, 09:25:35 pm »
I think they’re just wankers.

I’ve had four go on me. Most surprising was a Henry hoover.
Most distressing was a Kenwood Chef while the missus was on a Christmas cake binge.  :scared:
Smoke all through the kitchen and 'she' was not impressed......hates electricity !
Luckily a mate had one we could borrow to finish her binge so guess what he got for Xmas.  :)

So mechanical failure of the envelope is the mechanism rather than electro-thermal breakdown?

Hmmmm...

mnem
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Exactly.
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Offline Cerebus

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9673 on: April 24, 2018, 09:26:45 pm »
I think porosity, whether the cause of that porosity is purely mechanical or chemo-mechanical in nature, is a question yet to be answered.
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Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #9674 on: April 24, 2018, 09:35:11 pm »
Most distressing was a Kenwood Chef while the missus was on a Christmas cake binge.  :scared:

Ooh we've got one of them and it hasn't blown up yet. Might take it to bits and exorcise the bastard.
 


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