Test Equipment Anonymous (TEA) group therapy thread

[tggzzz]

High power transmitter tubes and magnetrons are still manufactured. Eimac is still in the business and as far as I know they still build their own transmitter tubes. In many applications they are still far superior to solid state. So how does that company recruit EE's who know diddly squat about vacuum tube theory?   

Traditionally a university education was supposed to be more about teaching you enough for you to be able to teach yourself. Hence the jump from undergraduate student to doctoral candidate, where you are supposed to be pursuing original research - by definition an area where nobody can teach you how it works because you're supposed to be discovering for the first time ever "how it works".

So in theory a graduate in any particular discipline has the tools at their disposal to further educate themselves in that discipline. Thus a competent EE graduate ought to be able to say "No, I don't know anything about vacuum tube technology but I know where the library is, and in a month I will know about vacuum tube technology".

That many graduates cannot do this is entirely the fault of employers who demand that universities turn out graduates who are ready to work with the flavour of the month instead of being grounded in the fundamentals of their discipline and the skills to teach themselves more. Similarly stupid thinking leads to people demanding recruits with 5 years experience of "currently fashionable technology" when "currently fashionable technology" only first appeared 3 years ago and reached commercial importance only 1 year ago.

And which specialized set of skills, once acquired, will be obsolete 10 years from now.    FML .

mnem
And yet the supply of such "management people" never dwindles...

Precisely. Isaac Asimov made me realise that via his story "Profession".

[Cerebus]

Easy to see you're not one of Jacobs fans either. I understood it that it was mandatory for all HoC staff to wear masks, but MPs were allowed to use their discretion?

I'm not a fan of anyone who smugly displays their ignorance and stupidity with the simpering self-satisfaction that he does, that's what has Rees-Mogg in my gunsights. Anyone who does the same would provoke the same reaction from me. It's the "don't be a silly little boy" attitude that he takes to anyone who correctly points he's being massively wrong, ill-informed or ignorant that gets my goat.

There's no shame in being ignorant, we all were once, and we can all learn. It's being proud of being wilfully ignorant that's a moral sin in my book.

Oh, and on the substantial point: I believe that The Speaker's word is law in regard to the conduct of business in Parliament and on the Parliamentary estate (Erskine-May would have the facts on this). The previous status quo was, as it is for the public, "use your discretion" but The Speaker changed that two days ago.

[mnementh]

...Similarly stupid thinking leads to people demanding recruits with 5 years experience of "currently fashionable technology" when "currently fashionable technology" only first appeared 3 years ago and reached commercial importance only 1 year ago.

And which specialized set of skills, once acquired, will be obsolete 10 years from now.    FML .

mnem
And yet the supply of such "management people" never dwindles...

Precisely. Isaac Asimov made me realise that via his story "Profession".

http://employees.oneonta.edu/blechmjb/JBpages/m360/Profession%20I%20Asimov.pdf

Yup... another of those cautionary tales where it seems TPTB instead chose to use it as a blueprint... 

mnem
please... learn from my mistakes; don't repeat them...

[mnementh]

...There's no shame in being ignorant, we all were once, and we can all learn. It's being proud of being wilfully ignorant that's a moral sin in my book.

Hear, hear. 

mnem
"You can't fix stupid, but there is a cure for ignorance: It's called curiosity." ~mom

[Specmaster]

@Cerebus, I totally agree with you about JRM, I'll never ever forget his arrogance and insensitivity over those poor victims in the Grenfell House horrific fire, who through no fault of their own suffered terribly doing what they thought was the best at the instructions of LFB. 

[Specmaster]

And now for something completely different, for all of those Land Rover fans and ex owners, I stumbled upon a different style of YT channel presenter, meet Sophie, yes Sophie is for real and a rare girl indeed, taking on Landies and restoring them doing all the dirty and hard work herself, including welding. Enough waffle from me, formulate your opinions, here is the link 

[Robert763]

Hmmmmm...

Maybe that would be a salable product...? A simple analog CRO for education with everything broken down into block diagrams, and the PCBs laid out in corresponding functional blocks and labeled accordingly...? Seems the curriculum would pretty much write itself after that point...

You know, since we can't just give them a 7000 series and plugins to tinker with.

mnem
 

These scopes are NOT for teaching electronics or how a 'scope works. They are for secondary school level physics. Guess why they have an X input on the front panel (hint it starts with L)
They need to mtch the simple drawings in the tesxt book.
In a similar vein that level of teaching also uses spring and beam balances when they are seldom found in a modern commercial lab.

[mansaxel]

"I am a White Male born & raised in America. Blaming everybody but myself is a cultural imperative, and may even be genetic."


By default yes you did and I resent that. But I am not going to discuss this further with you and your constant political bullshit.

I will hesitantly (because I do not want to further the debate too much) side with the Dragon here. He's got a point, and he made it pretty obvious, if wordy. That it seems to have gone past you is probably because, I suspect, you stop reading some sentences.  This time, that was sort of your loss. 

Walks of and tries to think of something on-topic to make amends by posting.

[factory]

Pretty sure there will be no tube theory at all when studying electronics nowadays, afaik some of the specialized tubes still in use today are bought from russia - maybe they still have at least one university teaching how and in which way to make them? With the death of fluorescent tubes the last remenants of technical glassworking are dying off in the west...

Quartz tubes are still needed without the fluorescent coating for UVC germicidal use.
The LED versions are supposedly very expensive and need the right material to survive the UVC & ozone produced. Bigclive on youtube has done lots of teardowns of cheapo LED ones, that have all been fake.

David

[factory]

   Submitted for Honorable Mention: The printer that will not die.

   Rubbish, allow me to introduce its executioner 

Even after you smash it with a post maul, there will be some printer nerd along in minutes and snatch the whole pile of bits off the curb into the back of his rusted out Corolla. Parts of it will live on in other 4250s.

mnem
true story.

Then he will chuck it back on the pavement, after finding out that the latest crApple OS update doesn't like it, along with many other old printers & scanners. 

David

[Cerebus]

Then he will chuck it back on the pavement, after finding out that the latest crApple OS update doesn't like it, along with many other old printers & scanners. 

David

Untrue. Because Apple uses CUPS (they wrote it) if you can get a printer to work on Linux you can get it to work on MacOS and vice-versa.

[mansaxel]

So, this week it is autumn break for the schools here. I've been working a bit less this week, and took the opportunity to finish a project that me and Middle Boy have been discussing, the First Stomp Box.  This one's a really easy one, just a switch and a LED in a 1590 style box. Its purpose is to switch from clean to lead channel on his guitar amp; the LED is simply in series with the switch and indicates "Lead channel" when lit.

TE used:

• Originally, to debug the interface⁰, my Fluke 27.
• To make certain I did not solder the switch wrong, and also got the LED the right way; the 8060.

Both meters of course are older than he is, and were chosen for being close by when we wanted to debug this. I think they suffice.

Footnote 0: The vendor, German brand Hughes & Kettner, sells the same style stomper, but call the function that one can light up a LED using the current that'll flow when you short the logic input to ground, "phantom" -- a description I take issue with, because it is not. A "phantom voltage" will exist in a circuit in a way that is independent from its usual current flow. Here, it is the same current that lights the LED and drives the input low, and therefore, it can't be a "phantom voltage".

[nfmax]

Another example. I don't know to what extent vacuum tube theory is still taught, if at all. Now when I was in school in the early 1970's it was over 50% of the curriculum. My recommendation for today's students is spend a class or two discussing diode and triode theory. If a student shows an interest in taking it further recommend good reference material for self-study.

I started my EE undergrad in 1978 and vacuum tubes weren't taught at all.  I I dropped out for a couple of years. When I started back in 1982 we were being taught IC design and SPICE.

0% valves for me '75-'78.

Was taught ICAP and ITAP simulation, equivalent to spice's ac and transient modes respectively.

Not only that, we were shown how to cold boot the Honeywell DDP516 they ran on, starting from setting up the toggle switches to load the paper tape that loaded the operating system from disc. Later on, that machine acquired a home-brewed EPROM programmer, which I used to program a 1702 (256 byte!) chip for my very first microprocessor project. Hand-assembled for the National Semiconductor SC-MP and typed in hexadecimal on an ASR33. Sometime in early 1977, I think it must have been. I still have it in a box somewhere

[factory]

Then he will chuck it back on the pavement, after finding out that the latest crApple OS update doesn't like it, along with many other old printers & scanners. 

David

Untrue. Because Apple uses CUPS (they wrote it) if you can get a printer to work on Linux you can get it to work on MacOS and vice-versa.

I'm only passing on what I read the other week on the vintage radio forum here; https://www.vintage-radio.net/forum/showpost.php?p=1412825&postcount=5
Need to be member with at least ten posts to read that section though, quote below.

Toner cartridges benefit from an occasional shake.

It looks like I need a new laser printer. An Apple OS update last year seems to have left all printer drivers behind and HP hasn't issued new ones for the new OS either. So my printer is bricked. Of course I only found out when I needed it. Think it's an HP lasertjet 1324nw I guess it's go on the offered section for someone with a compatible computer, once I've got a replacement, so I'm watching this thread with interest.

The colour laser I'm looking at seems to be out of stock everywhere... suspicious?

David

David

[factory]

As promised some teardown pictures of the Tektronix 321 oscilloscope s/n 000861.

....snip

Part two to follow....

Similar in layout but I see many differences between your Type 321 and my Type 321A.

I noted an extra transistor in the vertical circuit (some use FET instead of the Nuvistor too) , changes in the intensity circuit, probably lots of other small changes for the extra 1MHz bandwidth.

Edit: extra picture for teardown below.

David

[mnementh]

Hmmmmm...

Maybe that would be a salable product...? A simple analog CRO for education with everything broken down into block diagrams, and the PCBs laid out in corresponding functional blocks and labeled accordingly...? Seems the curriculum would pretty much write itself after that point...

You know, since we can't just give them a 7000 series and plugins to tinker with.

mnem
 

These scopes are NOT for teaching electronics or how a 'scope works. They are for secondary school level physics. Guess why they have an X input on the front panel (hint it starts with L)
They need to match the simple drawings in the text book.
In a similar vein that level of teaching also uses spring and beam balances when they are seldom found in a modern commercial lab.

That wasn't what I was saying... and yeah, the way you put it makes sense, but it's not necessarily a good thing that this sad example is the only thing available for educational use.

In my training we literally used our scopes to probe each other's scopes as part of the curriculum, so we understood the basic building blocks. Seems to me like maybe a scope made with that in mind would be a good idea; I was just wondering idly if it could be made a salable product?

mnem
 

[mnementh]

   Submitted for Honorable Mention: The printer that will not die.

   Rubbish, allow me to introduce its executioner 

Even after you smash it with a post maul, there will be some printer nerd along in minutes and snatch the whole pile of bits off the curb into the back of his rusted out Corolla. Parts of it will live on in other 4250s.

mnem
true story.

Then he will chuck it back on the pavement, after finding out that the latest crApple OS update doesn't like it, along with many other old printers & scanners. 

David

No he won't. He'll sell it for a tidy profit to some bass-ackwards corporate or .edu that still runs on AD, because it's still Plug & Play in that environment and is a 200,000 pages/month printer that all the "printer service" companies happily support.

mnem
*once upon a usedta-was printer nerd*

[factory]

.....Part two of the Tektronix 321 oscilloscope s/n 000861 teardown.

CRT HV pentupler multiplier, geometry adjustment and thermal cutout.


Bodged mains input, transformer & main filter caps.


Timebase switch and timing capacitors.




Timebase generator, trigger circuits and one of the troublesome pots (intensity) top left.



Vertical input & amplifier circuits, the other trouble pot (focus) top right.




David

[tggzzz]

Another example. I don't know to what extent vacuum tube theory is still taught, if at all. Now when I was in school in the early 1970's it was over 50% of the curriculum. My recommendation for today's students is spend a class or two discussing diode and triode theory. If a student shows an interest in taking it further recommend good reference material for self-study.

I started my EE undergrad in 1978 and vacuum tubes weren't taught at all.  I I dropped out for a couple of years. When I started back in 1982 we were being taught IC design and SPICE.

0% valves for me '75-'78.

Was taught ICAP and ITAP simulation, equivalent to spice's ac and transient modes respectively.

Not only that, we were shown how to cold boot the Honeywell DDP516 they ran on, starting from setting up the toggle switches to load the paper tape that loaded the operating system from disc. Later on, that machine acquired a home-brewed EPROM programmer, which I used to program a 1702 (256 byte!) chip for my very first microprocessor project. Hand-assembled for the National Semiconductor SC-MP and typed in hexadecimal on an ASR33. Sometime in early 1977, I think it must have been. I still have it in a box somewhere

Ah yes, the ddp516 with a 1000cps paper tape reader that could never meet modern safety regs, and a 10MB disc that was about 6ft in diameter.

I still have my first 6800 processor and the associated 128 byte RAM.Happy times.

[factory]

   Submitted for Honorable Mention: The printer that will not die.

   Rubbish, allow me to introduce its executioner 

Even after you smash it with a post maul, there will be some printer nerd along in minutes and snatch the whole pile of bits off the curb into the back of his rusted out Corolla. Parts of it will live on in other 4250s.

mnem
true story.

Then he will chuck it back on the pavement, after finding out that the latest crApple OS update doesn't like it, along with many other old printers & scanners. 

David

No he won't. He'll sell it for a tidy profit to some bass-ackwards corporate or .edu that still runs on AD, because it's still Plug & Play in that environment and is a 200,000 pages/month printer that all the "printer service" companies happily support.

mnem
*once upon a usedta-was printer nerd*

Don't know about that, the company my Dad worked for and the corporate I work for, have replaced all stand-alone printers with a few big network connected photocopiers.

However the lab rarely had any money invested in new TE and there is a PC running windows 98 for Metcal.
And the medical room has an old Toshiba laptop running windows 95 for hearing tests, had one a couple of days ago, the audiometer looked something similar to this, even down to the bust screen. 


David

[Specmaster]

   Submitted for Honorable Mention: The printer that will not die.

   Rubbish, allow me to introduce its executioner 

Even after you smash it with a post maul, there will be some printer nerd along in minutes and snatch the whole pile of bits off the curb into the back of his rusted out Corolla. Parts of it will live on in other 4250s.

mnem
true story.

Then he will chuck it back on the pavement, after finding out that the latest crApple OS update doesn't like it, along with many other old printers & scanners. 

David

No he won't. He'll sell it for a tidy profit to some bass-ackwards corporate or .edu that still runs on AD, because it's still Plug & Play in that environment and is a 200,000 pages/month printer that all the "printer service" companies happily support.

mnem
*once upon a usedta-was printer nerd*

All of this one up man ship is pointless really because if the person wielding the wildizer does his job correctly then there will be nothing left that would be of any use to that nerd with the rusty old Corolla to snatch up from the curb and chuck into its back for use in other 4250s. 

Ain't I a stinker

[Neomys Sapiens]

#3

I have realized that my DSO (Rigol DS1202Z-E, 2-channel, 200MHz) does poorly in X-Y mode. Yes, it works very well, but only within some very tight parameters. If it's zoomed in too much, I just get a few dots on the screen. If the data to be displayed is changing over time (in the scale of second by second), for example, the scope can't keep up and only displays a slideshow. Now keeping an eye out for a compact, cheap 2 channel CRO. That Sony/Tek scope is in the right ballpark.

EDIT:

Thanks, 25 CPS, for mentioning XY mode.

Yes, and this holds basically true for all sampling scopes. It is one reason for me seeking to aquire a Tek22xx besides a new high-performance DSO. If it happens to be a 2232, backup portable DSO comes on top, if it will be a 2236, blue display counter/VOM - but mostly for getting a better non-sampled and X/Y-capable scope.

[tautech]

X-Y is pretty good in the modern DSO.

[Neomys Sapiens]

The RF Amplifier in our old (2007) MRI scanner used two vacuum tubes in the final.   Our new scanner is all solid state.

The Korg 6P1 dual triode is made in Japan.   I've thought about buying a pair to tinker with.  RS has them in stock.

Until now, I have only seen sompe pictures of it and thought of it as a curiosity. But Valves being Valves - is that thing usable for RF?

[Cerebus]

The RF Amplifier in our old (2007) MRI scanner used two vacuum tubes in the final.   Our new scanner is all solid state.

The Korg 6P1 dual triode is made in Japan.   I've thought about buying a pair to tinker with.  RS has them in stock.

Until now, I have only seen sompe pictures of it and thought of it as a curiosity. But Valves being Valves - is that thing usable for RF?

Out of curiosity I had a look at the data sheet a few weeks back. They are crappy valves on almost all parameters: 1.4 mW max, anode resistance 330k, f_t around 30-40 kHz, yadda, yadda, yadda.

They are a curiosity rather than a useful component.

Here's the data sheet: