OT - CRT's

On a sunny day (Thu, 23 May 2019 22:19:01 -0700 (PDT)) it happened snipped-for-privacy@gmail.com wrote in :

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Scopes ANALOG scopes I have used to repair maybe a few thousand TV sets, VCRs, what have you, studio equipment like quadruplex recorders, cameras, no end to it, system converters, and I still have my Trio 10MHz dual channel TV repair scope as main scope and it still works after 2019 - 1979 = 40 years! ONE repair job when I accidently touched a booster output (few kV) with the probe, and few years ago the soldering station dropped from the table on it and cracked the graticule, so I made a new graticule. Quality!

Before that I first build a tube one with DG7-32 CRT early sixties, mostly from some circuit I found in some magazine. the second one was my own design (1968 or so) and used RTL logic, the same CRT, had triggering, and the third one was later, a 300 MHz bandwidth with an East German CRT and based on a Tek circuit they accidently published in some magazine. Talked to that guy later at Tek, he had a lot of headwind because he publised that, he told me. Then I moved to on other place an donated the whole stuff..

So, now, and yesterday after reading all this, I checked ebay for CRTs, found even my old DG7-32, many different Russian CRTs, so there is noting in the world here why you cannot build a fast analog scope as to 2019!!!

It is : The player, NOT the instrument. That is why I still have not bothered to buy boat anchors and Rigols and what have you, a new digital one appears every year from China. Important is that you understand the circuit, understand how the scope works and what it really shows. Maybe a wet finger can then replace many thousand of dollars of equipments, a clue will do, I agree with Joerg, I use my SSB radio a lot... for precision things like locking to rubidium reference check etc, Some people stuff their 'lab' full of multi million dollar impressive looking stuff. But a clue, just ONE clue, is a lot cheaper. And in broadcasting it was always the result that counted, the show must go on, freaked out directors and artists is a heavy load if a camera or recorder breaks down, transmitting 'black' is a nono, find a way. I have done that for many years, and always the show went on. Clues and in depth knowledge of the equipment you are facing is essential for fault finding. So is improvisation if under pressure. Just wanted to say that, most people work without a minutes timeline. And 'tronix is simple!

Reply to
Jan Panteltje
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Didn't you know? Every last bit of any limited resource has to be divvied out to the majority chattering hordes, especially when doing so helps the government's budget. The idea that some should be kept back for minority use... that's communism, or racism, or whichever ism is most likely to have the effect of suppressing dissent. Will no one think of the children?

Sylvia.

Reply to
Sylvia Else

Er, that ended up in the wrong place, somehow - probably my ageing fingers. It was meant to be about 24GHz.

Sylvia.

Reply to
Sylvia Else

Phil Hobbs wrote in news: snipped-for-privacy@supernews.com:

CQ501

Tek makes extremely good gear!

Reply to
DecadentLinuxUserNumeroUno

John Larkin wrote in news: snipped-for-privacy@4ax.com:

It was my understanding that CRTs ALL have magnetic field beam deflection... in both vectors.

Reply to
DecadentLinuxUserNumeroUno

AK wrote in news:5ff11d39-9745-43cd-9652- snipped-for-privacy@googlegroups.com:

Leaded glass is not an environmental hazard. It has NEVER been one.

So my question is How can "science" be part of your email address when "science" is no part of your understanding of the world?

Reply to
DecadentLinuxUserNumeroUno

snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@googlegroups.com:

Remember before DVDs that a CD had a rating of AAD ADD or DDD. This refered to the path the signal took to get put onto the disk. That declaration of how the CD was made was important say in classical renderings

A DDD disc is rare as the musical instrument itself is analog.

And still, after all the quaintisization, the finished product is an analog signal 100% representative of the original instrument's analog product.

Reply to
DecadentLinuxUserNumeroUno

Nope. Scopes are all-electrostatic. That's why they don't focus as well as CRT TVs.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
http://hobbs-eo.com
Reply to
Phil Hobbs

No, but I have a couple of the extension cables, which are still rare and expensive. It's great to get the sampling head a few inches from the signal source. Really fast signals don't travel well over feet of coax. Which is why I wonder what is the utility of that million dollar

100 GHz LeCroy scope someone posted a link to... how go you get a signal to it?

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I have posted pics of the guts of the SD24 TDR head. I can do that again if anyone is interested.

Hey, the pics are online:

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--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics
Reply to
John Larkin

Not always. I've had bugs in newer Tek scopes, and support has been terrible. We buy Rigol now.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
Reply to
John Larkin

Here's the CRT from a Tek 547. The vertical deflection plates are actually a delay line so the deflection voltage tracks the electron velocity. Beautiful piece of glass. The electron optics was probably the best of any scope.

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547 was a beautiful scope. I still have a few.

The 519 tube is more extreme, 1 GHz bandwidth, but the vertical deflection goodies are hidden inside a box.

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It looks like they tuned the location of each deflection segment. Operating? In a vacuum? Did the tech wear a space suit?

Later tube scopes used post-deflection-mesh CRTs to increase vertical sensitivity and make the tube shorter. That really wrecked spot size.

Hamamatsu made a tube-based sampling scope with optical input, basically a streak tube with a slit and a PMT as output. I saw a demo at the factory, but I don't think they ever commercialized it.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
Reply to
John Larkin

That sweep is 50 ps/div!

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
Reply to
John Larkin

OK, we'll forget the children.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
Reply to
John Larkin

I have a customer who wants us to make a 3-phase 400 Hz power source to simulate a PM alternator. I was thinking we could buy some already-built class-D amp boards to do the power bits, say 150 watts per channel or so. I'd rather buy than build that part.

We could use three of this eval board (we have a couple and they work great) but they are big and have goofy connectors...

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Like most eval boards, it has a zillion jumper options.

Can anyone suggest a good-quality small equivalent class-D amp board? We wouldn't want to use the really cheap ebay stuff which might not be available next month.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
Reply to
John Larkin

They probably did that in TDR-fashion in open air.

It's all going digital which, for nasty noise hunts, isn't so great.

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

John Larkin wrote in news: snipped-for-privacy@4ax.com:

instruments/TPA3255

Spin your own. Would not be much more than ebay jobs are. Quick turn board houses are there for proto experimentation runs.

What you do is buy a couple cheap ebay jobs and use their design ideas in making one of your own utilizing your years of experience with compnonet placement thermal abatement, etc.

The base circuits are out there from cheap to perfectly and fully conditioned and tuned.

And in your case, then you make three... one for each phase.

Reply to
DecadentLinuxUserNumeroUno

We could just crib the TI eval board circuit (that's what eval boards are for) but that's still a project. Design, layout, assembly drawings, BOM, test procedure, a zillion docs to release. I'd rather buy something if it exists. Quantities will never be big here.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics
Reply to
John Larkin

fredag den 24. maj 2019 kl. 18.14.38 UTC+2 skrev John Larkin:

something here?

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some even include universal mains supply

Reply to
Lasse Langwadt Christensen

CRT scopes are normally electrostatic. Early TVs were too.

NT

Reply to
tabbypurr

I'm surprised that some audiophool has not come up with a product that uses it (small scope tube) as an amplifying device. I'm tempted to submit an article to a hi-fi magazine for publishing next April.

Reply to
grahamholloway

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