Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

I just had the fancy for a ultrasonic cleaner thats big enough to accept a PCB of approx 200 x 200 until I saw the prices of those things, geez why are they so bloody expensive 

Short version: RMS factoring of the emitter power/driver circuitry required to actually do the job vs volume. Log scale in power, log scale in price vs actual usable volume.

mnem
 

What?

Required power to sufficiently energize a tank full of solution roughly follows the same RMS power factoring as power required for loudspeakers/amplifiers in any given volume in air; it is not linear it is a log scale. Only difference is the starting point of the scale, because Watts/CC liquid vs Watts/CC air.

As a result, cost is similarly not a linear scale.

mnem
*nonlinear*

Oh, I see. I just assumed that the bigger units were just scaled up versions of the little jewellery ones that you get that judging from the hum and the detectable vibrations were generated by small motors that were very slightly off balance and that caused the oscillations in the cleaning fluid to agitate the dirt and effectively get scrubbed by the liquid, no?

[med6753]

Geez, I go off to do some constructive work and I come back to pages of bitching and moaning. 

Anyway. IT'S ALIVE!  No smoke, no flames, no fuss.

Dragon....your thoughts about that HV rectifier being for a microwave appear to be correct. 

https://www.eevblog.com/forum/repair/repairrestoration-of-a-tek-type-561b/msg3093846/#msg3093846 

[mnementh]

OK, the disposable light bulb did become "better" as a result of all the guts becoming cheaper, right?  -  Tech has been built into cars that would not have been possible in the past.  How many microprocessors are there in the typical mid range car these days?  Quite a few...

I think it is only too easy to catch a bit of the "boiled frog syndrome" to some extent in daily life - it doesn't take long to take a new level of existence for granted  (until you lose it!)

Better for the people in the oil industry, and big power in general, yes.

The oil people (the only people who really matter in today's world) get more of their money up front in terms of the oil used to make the plastics and all the electronics, which is dozens of processes and factories where we used to have a couple processes making metals and glass for incandescent. Big power passes the slight increase in cost of fuel per watt over the decades to the end-user twenty-fold; and they get to continue charging almost exactly the same now per customer as they did 30 years ago for much less electricity per capita, while still serving 3 times as many customers with the same outdated core infrastructure.

Meanwhile, light bulbs SHOCKINGLY still continue to burn out left and right, only now they cost more per unit and the spent one is made of 60 different kinds of toxic materials, making them essentially recycling nightmare e-waste waiting to happen, while a incandescent bulb is 100% easily recyclable glass/metals, but very little to no plastic and production requires only a few energy-consuming processes which make money for oil people.

Remember too, that at the same time as we introduced energy-efficient light bulbs, we ALSO introduced smart controls for those lights which make them able to turn themselves off. More money from plastics and electronics manufacture yet again for big oil, but also, that fact greatly skews the supposed "savings" in energy over incandescent. If those same smart controls had been as habitually applied to incandescent lighting before the advent of these low-energy light bulbs, I suspect the real energy and cost savings vs prior generations would have proven to be much less dramatic.

mnem
Simplify.

[mnementh]

I just had the fancy for a ultrasonic cleaner thats big enough to accept a PCB of approx 200 x 200 until I saw the prices of those things, geez why are they so bloody expensive 

Short version: RMS factoring of the emitter power/driver circuitry required to actually do the job vs volume. Log scale in power, log scale in price vs actual usable volume.

mnem
 

What?

Required power to sufficiently energize a tank full of solution roughly follows the same RMS power factoring as power required for loudspeakers/amplifiers in any given volume in air; it is not linear it is a log scale. Only difference is the starting point of the scale, because Watts/CC liquid vs Watts/CC air.

As a result, cost is similarly not a linear scale.

mnem
*nonlinear*

Oh, I see. I just assumed that the bigger units were just scaled up versions of the little jewellery ones that you get that judging from the hum and the detectable vibrations were generated by small motors that were very slightly off balance and that caused the oscillations in the cleaning fluid to agitate the dirt and effectively get scrubbed by the liquid, no?

No... small ones use cheap piezo drivers that actually form part of the oscillator circuit and are pretty efficient up to their limits. Larger ones use purpose-built motor assemblies that are more complex to drive, less efficient and require cleaner signal/drive current to produce the correct frequencies. If not driven correctly they can self-destruct, while the cheap piezo tends to self-correct to its own resonant frequency.

Then, you factor in the log scale as far as Watts/CC.

mnem
*~~~~~tsssshhhhhhhhhhhhhhhhhhh~~~~~*

[mnementh]

Geez, I go off to do some constructive work and I come back to pages of bitching and moaning.  Anyway. IT'S ALIVE!  No smoke, no flames, no fuss. Dragon....your thoughts about that HV rectifier being for a microwave appear to be correct. 

https://www.eevblog.com/forum/repair/repairrestoration-of-a-tek-type-561b/msg3093846/#msg3093846

Looks good! Even the ol' dwagon can be right once in a while... 

Dunno whether to be glad there were no sparkies or not... Now you have to go find something else to work on! 

mnem
 

[Cerebus]

EDIT: C, I love you man but just looking at your examples kindof proves my point... they're all pretty much from the dark ages. 

Your point appeared to be that elbow patches are haute couture, they are not, in any age or at any age.



Anyway, I've had the 70's on the phone again and they're getting really quite shirty about those jeans. Be a good fellow and pop them in the post will you, and let the 70's know you've done it.

[SilverSolder]

OK, the disposable light bulb did become "better" as a result of all the guts becoming cheaper, right?  -  Tech has been built into cars that would not have been possible in the past.  How many microprocessors are there in the typical mid range car these days?  Quite a few...

I think it is only too easy to catch a bit of the "boiled frog syndrome" to some extent in daily life - it doesn't take long to take a new level of existence for granted  (until you lose it!)

Better for the people in the oil industry, and big power in general, yes.

The oil people (the only people who really matter in today's world) get more of their money up front in terms of the oil used to make the plastics and all the electronics, which is dozens of processes and factories where we used to have a couple processes making metals and glass for incandescent. Big power passes the slight increase in cost of fuel per watt over the decades to the end-user twenty-fold; and they get to continue charging almost exactly the same now per customer as they did 30 years ago for much less electricity per capita, while still serving 3 times as many customers with the same outdated core infrastructure.

Meanwhile, light bulbs SHOCKINGLY still continue to burn out left and right, only now they cost more per unit and the spent one is made of 60 different kinds of toxic materials, making them essentially recycling nightmare e-waste waiting to happen, while a incandescent bulb is 100% easily recyclable glass/metals, but very little to no plastic and production requires only a few energy-consuming processes which make money for oil people.

Remember too, that at the same time as we introduced energy-efficient light bulbs, we ALSO introduced smart controls for those lights which make them able to turn themselves off. More money from plastics and electronics manufacture yet again for big oil, but also, that fact greatly skews the supposed "savings" in energy over incandescent. If those same smart controls had been as habitually applied to incandescent lighting before the advent of these low-energy light bulbs, I suspect the real energy and cost savings vs prior generations would have proven to be much less dramatic.

mnem
Simplify.

Don't get me wrong, I share your skepticism about many of the improvements, hence putting "better" in quotes...

But even if there is a lot of BS going on,  this is just part of the human condition...  we are really good at BS...   -  but there are definitely also underlying, real improvement going on too, if you look behind the BS.   The underlying real rate of improvement is probably around 2% per year, whereas BS seems to grow at 10% per year!   

[worsthorse]

Well, I think we are probably through the worst of it around here.  I hope to be hanging out on the forum and at my bench again, albeit at a reduced frequency, and having time to put into some of my long stalled projects. I did spend a couple of hours on the S38, and made enough progress to fix the worst of the hum problems and make a hypothesis regarding what remains to be done.

And, of course, since I am a glutton for punishment, the day after I shipped the parts mule 184 to someone I figured could use it more than me, I decided this was a good idea:

    

Yes, another 184. The seller said it worked. Though the oven light comes on, it doesn't power up. Probably a DC supply problem because it is in pristine, unaltered shape. The good news is the seller refunded a substantial portion of the purchase price rather than deal with a return. If I get it working, it will turn into a very good deal.

[VK5RC]

Re Amateur Radio societies, be careful of dissing them too much - in  VK land, another organization sprung up with a far more technical focus, our Federal registration process for decades was run through our major Amateur radio organisation, the WIA, you could get a licence in a month, know the answers instantly. The alternative group felt that the WIA was not operating the exams properly, and the Federal body, put out tenders, because of issues with what is a ' Registered Training Organisation' the WIA  lost. The exams are now run by a RTO run out of one state (Tasmania) , exams take months to organize, very little candidate feedback happens , the cost has gone up and the number of new Hams has plummeted.
Don't get me wrong, I have some minor issues with the WIA, but what a CF it is now.

[Kosmic]

[...]
- Your instruments are detected and controllable using NI VISA (finding them, sensing commands, reading data) with no action required on the PC side.
  They are found as ASRL:COMxx, you can open, send, write, read, query, ...

What is the benefit of using NI VISA, compared with hitting the instruments directly over the serial port from inside your program?  (Especially if you are not using LabView etc.)

That's how I do it over GPIB -  straight commands to each instrument, and processing the responses in the application (whether the instrument uses SCPI or even older, instrument specific protocols)

Of course you may do that, and it works. The reason why I chose VISA was:
- all my other commercial lab stuff uses it and they have no serial connectivity but USB
- VISA does some housekeeping (timeouts, error handling, ...) you would have to duplicate
- there is a prefabricated front-end (NI Explorer) handy for testing
- Its no more effort than serial because I need VISA anyway
- I dont like the same things to be done in a lot of different ways.

I also use VISA to interface with my TE. I like how it create a nice abstraction between the application and the controller used to talk to the TE. Also make things a lot simpler in your application since, like wolfgang mentioned, they handle bunch of details under the hood.

[xrunner]

Remember "dip meters"? A friend of mine was wanting to check some coils and he asked me if I knew how to do it. I remembered I had an old Kenwood dip meter and said if he wanted to use it he could borrow it. He doesn't have much in the way of test equipment.

I checked it out to see if it still worked - it did. With a 10 uH inductor and a 10 pF cap, which calculates to 15.92 MHz resonant freq. it had a good dip at 15.2 MHz which is close enough.

I told him he could use a known capacitor with his coil and look for a dip and just re-arrange the classic formula for resonant frequency to solve for inductance, knowing the frequency and capacitance. He laughed and said re-arrange whaaaaaat? LOL I said I will do that for you.

So we will see if he wishes to try it. My guess is ... no. 

[0culus]

Well, I think we are probably through the worst of it around here.  I hope to be hanging out on the forum and at my bench again, albeit at a reduced frequency, and having time to put into some of my long stalled projects. I did spend a couple of hours on the S38, and made enough progress to fix the worst of the hum problems and make a hypothesis regarding what remains to be done.

And, of course, since I am a glutton for punishment, the day after I shipped the parts mule 184 to someone I figured could use it more than me, I decided this was a good idea:

    

Yes, another 184. The seller said it worked. Though the oven light comes on, it doesn't power up. Probably a DC supply problem because it is in pristine, unaltered shape. The good news is the seller refunded a substantial portion of the purchase price rather than deal with a return. If I get it working, it will turn into a very good deal.

Definitely appreciate getting the parts unit from you.  As for mine, the gremlins seem to keep coming. I got all the low frequency sine markers to work by tube swapping with the parts unit, but now the HF oscillator is totally dead. I also noted that something has changed and the large inductor on the 500 MHz board no longer has +125V on it. Might have a cold joint or something...

[0culus]

184 update: I think the V60 and V70 tube sockets may be flaky on mine. Continuity testing shows that some pins are shorted together that are not on worsthorse's parts unit.

[jxjbsd]

Yesterday, in order to fix the trigger part of the 7B10 plug-in, I carefully read the basic principles of the trigger part and the trigger part of the Tektronix service manual.  The fault is very strange, the boot is normal, it can not be triggered normally after 5-10 minutes, and finally locate the 155-1150 IC, the voltage waveform is tested, but there is no progress , so I have to go to sleep.  I suddenly thought this morning that the IC may not be in good contact. I removed the pin and pulled it. After installing it, everything was normal. 
It seems that rest is very important. 

[mnementh]

EDIT: C, I love you man but just looking at your examples kindof proves my point... they're all pretty much from the dark ages. 

Your point appeared to be that elbow patches are haute couture, they are not, in any age or at any age.   

Anyway, I've had the 70's on the phone again and they're getting really quite shirty about those jeans. Be a good fellow and pop them in the post will you, and let the 70's know you've done it.

My point was quite the opposite; that iron-on patches long ago grew up. They’re a utilitarian object, meant to fix and protect clothes and nobody cares about them anymore. You can even see them on the evening news doing their job, they’re so “Nobody GAF about them”.

You are the one who seems hellbent on making a fashion statement of them; I really couldn’t care less. But since dwagons don’t actually wear pants, pretty sure those aren’t mine.

Perhaps you should hop along and put those back in the Queen Mum’s hope chest where you found them, before they’re noticed missing and someone decides it’s time for the Corgis to have a little aardvark stew....

mnem
*knocks self unconscious with a anthill mallet* 

[worsthorse]

Well, I think we are probably through the worst of it around here.  I hope to be hanging out on the forum and at my bench again, albeit at a reduced frequency, and having time to put into some of my long stalled projects. I did spend a couple of hours on the S38, and made enough progress to fix the worst of the hum problems and make a hypothesis regarding what remains to be done.

And, of course, since I am a glutton for punishment, the day after I shipped the parts mule 184 to someone I figured could use it more than me, I decided this was a good idea:



Yes, another 184. The seller said it worked. Though the oven light comes on, it doesn't power up. Probably a DC supply problem because it is in pristine, unaltered shape. The good news is the seller refunded a substantial portion of the purchase price rather than deal with a return. If I get it working, it will turn into a very good deal.

Definitely appreciate getting the parts unit from you.  As for mine, the gremlins seem to keep coming. I got all the low frequency sine markers to work by tube swapping with the parts unit, but now the HF oscillator is totally dead. I also noted that something has changed and the large inductor on the 500 MHz board no longer has +125V on it. Might have a cold joint or something...

The 184 design pushes all the parts right to their edges. The downside of that is when the damn things stop working, the failure modes are complicated and (at least for me), hard to figure out. The parts mule I finally gave up on after a month of chasing the failure that seemed to move around the countdown board; I could never pin it down.

But that bleeding edgeness is what makes it such an interesting box and why I faltered and bought another one knowing that fixing it will probably be another teeth grinding experience.

Power faults are pretty easy, relatively speaking. Hope you get yours tracked down soon.

[0culus]

Well, I think we are probably through the worst of it around here.  I hope to be hanging out on the forum and at my bench again, albeit at a reduced frequency, and having time to put into some of my long stalled projects. I did spend a couple of hours on the S38, and made enough progress to fix the worst of the hum problems and make a hypothesis regarding what remains to be done.

And, of course, since I am a glutton for punishment, the day after I shipped the parts mule 184 to someone I figured could use it more than me, I decided this was a good idea:



Yes, another 184. The seller said it worked. Though the oven light comes on, it doesn't power up. Probably a DC supply problem because it is in pristine, unaltered shape. The good news is the seller refunded a substantial portion of the purchase price rather than deal with a return. If I get it working, it will turn into a very good deal.

Definitely appreciate getting the parts unit from you.  As for mine, the gremlins seem to keep coming. I got all the low frequency sine markers to work by tube swapping with the parts unit, but now the HF oscillator is totally dead. I also noted that something has changed and the large inductor on the 500 MHz board no longer has +125V on it. Might have a cold joint or something...

The 184 design pushes all the parts right to their edges. The downside of that is when the damn things stop working, the failure modes are complicated and (at least for me), hard to figure out. The parts mule I finally gave up on after a month of chasing the failure that seemed to move around the countdown board; I could never pin it down.

But that bleeding edgeness is what makes it such an interesting box and why I faltered and bought another one knowing that fixing it will probably be another teeth grinding experience.

Power faults are pretty easy, relatively speaking. Hope you get yours tracked down soon.

Yeah. The 500 MHz subsystem in particular is pure black magic. After swapping the 500MHz boards (the one that came in mine definitely has bad sockets for the two tubes), I finally found the right combo of tubes and adjustments to finally get the 500MHz marker to come in. I had to tweak the geometry of L69 relative to L70 (the giant wishbone) to get it to finally work.  Now, as far as I can tell, all markers are working!

[edavid]

Possibly nice deal in US: Fluke 27/FM + HV probe: https://www.ebay.co.uk/itm/143628599383

Edit: cheaper one, with HV probe but no case: https://www.ebay.co.uk/itm/133435408340

These are examples of the AN/PSM-45A kit that was procured by the US military.  For a while there were zillions of them on eBay.

(There was an earlier AN/PSM-45 that was similar, but included a Simpson 467 DMM and an external 10A shunt.)

[tggzzz]

I had to tweak the geometry of L69 relative to L70 (the giant wishbone) to get it to finally work.  Now, as far as I can tell, all markers are working!

Ditto with mine. I also had to replace one nuvistor; fortunately there are stocks around for reasonable prices.

[bd139]

Heads up for UK ebay users. It's £1 max fees per listing for 10 days. Best time to clear out and best time to take advantage of people clearing out 

[med6753]

More progress and set backs.....

https://www.eevblog.com/forum/repair/repairrestoration-of-a-tek-type-561b/75/

The good news is I sold a working DM44 circuit board assembly to someone on the Tek Scopes Facebook List. Will help to off set the cost of my new money pit. 

[bd139]

I admire your fight on this one. I'd have parted the bastard out by now 

[tggzzz]

Heads up for UK ebay users. It's £1 max fees per listing for 10 days. Best time to clear out and best time to take advantage of people clearing out 

Or merely re-list the treasures you are already trying to shift

[tggzzz]

I admire your fight on this one. I'd have parted the bastard out by now 

I'm feeling a little fey this morning. I won't suppress the thought that that puts me in mind of errant children or SOs - in different ways, of course.

[med6753]

I admire your fight on this one. I'd have parted the bastard out by now 

I'm feeling a little fey this morning. I won't suppress the thought that that puts me in mind of errant children or SOs - in different ways, of course.

"Fey"  ?  Had to look that up. I guess I lack sophistication.  "SOs" escapes me too.

So pray tell, what does you crystal ball say?