Test Equipment Anonymous (TEA) group therapy thread

[Ero-Shan]

My most recent TEA was at work, so I have a little bit of equipment in my office rather than have to go to the lab. Besides, some genius blew up the frontend of the (extremely expensive) Keysight scope in the lab...so it's nice to have my own. 

Let me guess - you have simultaneously discovered my idea: make the company buy now what you will make it shed in a year (into your waiting hands), as you are in control of the specification, which has to keep up with the newest developments, of course...
And make them shed it into your hands without a real payment, as it is to be the compensation for tools and instruments already provided by you to them. Which gives you a constantly growing pool of assets , for the use of which you can take control of even more of the preexisting lab equipment.
Well played, dear colleague!

Why, yes!  In other news, the LeCroy 9450 I acquired for my office is a really slick scope...and the crt is in good shape...no burn in, bright and crisp. The orange phosphor is pleasing to look at as well. Looked up catalog prices, and it was ~20k yankee bux in 1990.

I can only agree with you. Especially in 1990 this scope was a dream to work with. What I didn't like is that LeCroy moved the power switch from the front panel (9400) to the instrument's back. I usually used it standing on the floor, as it is exceptionally deep, and reaching for it was a PITA.
And the worst problem of all the LeCroys is that their dual potentiometer based controls invariably get cranky. On my 9450 it is virtually impossible to set the cursors where I want them - when you're almost there, they jump all over the place.

[mnementh]

Sounds like old man Kirsch... who, after we put LV electrolytics in the outlet strips on his bench, adjusted our attitudes by relocating those caps to OUR workbenches (of course he knew who the perpetrators were by that time) and turning them off at the breaker box behind the door, where he could set them off for best effect during workbook time.  

I was the only one who noticed the caps BEFORE the fireworks... because I actually followed his lab checklist EVERY TIME and MADE SURE of what was plugged into the power strip, and that it was turned OFF before I sat down.

"I'm going to have to watch you, young man." was all he said.

In my high school electronics vo-tech class, each bench was equipped with a RCA trainer rack, which held a variety of single purpose plugins - filters, amplifiers, oscillators, and of course, power supplies.  To improve the learning experience the back of each plug-in had a few components that could be changed, mounted on phenolic board plugins. Including, of course, the power supply.  This being the seventies, these were vacuum tube circuits, with the attendant voltages.

Now why anyone thought it was a good idea to let teenagers loose on these things, I don't know, but it didn't take long to envision what a spectacular flash-bang there'd be if one, umm, accidentally reversed one of the plug-in electrolytics on the power supply plugin. Even better if the boom occurred at the bench of the class bully.

I was the meekest kid in the room and so not on the short list of suspects, though I imagine Mr. Menzie had a notion...

LOL... I got to know Kirschy pretty well over the years at my High school; and discovered later that this was in fact a compliment. I took every course of his I could (including all the metal shop ones). I remember when he was doing his "Introduction to Electricity" stuff... he was talking about AC power, the shape of the sine wave and what it meant, and I made some comment about 240V and 3-phase, thinking I knew what I was talking about. "Household wiring has the same three legs, but it isn't 3-phase. Three phase is something completely different."

Frustrated, I asked him "What's the difference then?" He didn't say anything, but instead quickly sketched out the 4 quadrants & dotted line we all knew by then represented the screen of an oscilloscope on the chalkboard. I stood up, watching him, and as he drew the staggered traces of 3-phase AC power, it dawned... I grokked a whole new level of understanding. "I said an enthusiastic "Thank you, sir!" and sat back down, whereupon he immediately went back to the lesson at hand, while I pondered everything that exchange revealed to my budding mind. Questions of how a transformer could pass the waveform unmolested, how a 3-phase transformer might be made differently... how even modern electric motors were almost all 3-phase motors, and the run capacitor just simulated the 3rd phase all fell into place. It was a "That's good; you've just taken your first step into a larger world." moment for me.

I don't think I've ever had a single teacher (except maybe one math teacher who actually made quadratic equations accessible to my mechanical mind) who taught me as much as he did.



mnem
*toddles off to ded*

[bitseeker]

Imagine that, buying a piece of test gear that I don't have to tear open and repair before using it. 

I’m still trying to get over the fact it had all four feet. 

I concur with both sentiments.

[bitseeker]

I played around a bit with my new (to me) SA and bg7tbl nose (sic) source. The SA seems to be in really good condition. I was most worried about the front panel because so many Advantest SA have cracked or completely broken off edges. The seller did a great job shipping it.

Quick check of the 30 MHz, -10dBm cal signal. I don't have a short calibration cable, so there's a couple dB loss over the 1m coax.



The noise source is pretty good over the first 500 MHz.



Loses another 5 dB on the way to 1 GHz.



And really takes a dive before it gets to 2 GHz.



Is it normal for the trace to be so thick (is that what you call it)? I'm an SA noob and this one being a used machine of unknown history doesn't help with knowing what to expect as normal. The cal signal looks reasonable to me.

Next question is how to best test out the bandwidth of the scope probes since I don't have those probe-to-bnc adapters.

[Specmaster]

Couldn't resist an HP 6296a - in not bad shape - ended up for $ AUD 73, 60V 3A. Down-under prices are pretty high.

My one nasty connection with the national grid (230v) unfortunately gripped my hand onto the DUT and the power - only way I could let it go was to throw the whole assembly (an amp) across the room, the connection point burnt into my left thumb about 3mm, I still have the scar. I have a lot of respect for anything over 60V. Earthing, earth leakage detection, a foot operated 'dead man pedal' (ie take your foot off and the circuit de-powers) are now essential in my book.

What, you had no earth leakage detection at all? [emoji53] Well I sincerely hope that others reading this will now, like you, be getting themselves that level of protection.

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[Specmaster]

Sounds like old man Kirsch... who, after we put LV electrolytics in the outlet strips on his bench, adjusted our attitudes by relocating those caps to OUR workbenches (of course he knew who the perpetrators were by that time) and turning them off at the breaker box behind the door, where he could set them off for best effect during workbook time.  

I was the only one who noticed the caps BEFORE the fireworks... because I actually followed his lab checklist EVERY TIME and MADE SURE of what was plugged into the power strip, and that it was turned OFF before I sat down.

"I'm going to have to watch you, young man." was all he said.

In my high school electronics vo-tech class, each bench was equipped with a RCA trainer rack, which held a variety of single purpose plugins - filters, amplifiers, oscillators, and of course, power supplies.  To improve the learning experience the back of each plug-in had a few components that could be changed, mounted on phenolic board plugins. Including, of course, the power supply.  This being the seventies, these were vacuum tube circuits, with the attendant voltages.

Now why anyone thought it was a good idea to let teenagers loose on these things, I don't know, but it didn't take long to envision what a spectacular flash-bang there'd be if one, umm, accidentally reversed one of the plug-in electrolytics on the power supply plugin. Even better if the boom occurred at the bench of the class bully.

I was the meekest kid in the room and so not on the short list of suspects, though I imagine Mr. Menzie had a notion...

LOL... I got to know Kirschy pretty well over the years at my High school; and discovered later that this was in fact a compliment. I took every course of his I could (including all the metal shop ones). I remember when he was doing his "Introduction to Electricity" stuff... he was talking about AC power, the shape of the sine wave and what it meant, and I made some comment about 240V and 3-phase, thinking I knew what I was talking about. "Household wiring has the same three legs, but it isn't 3-phase. Three phase is something completely different."

Frustrated, I asked him "What's the difference then?" He didn't say anything, but instead quickly sketched out the 4 quadrants & dotted line we all knew by then represented the screen of an oscilloscope on the chalkboard. I stood up, watching him, and as he drew the staggered traces of 3-phase AC power, it dawned... I grokked a whole new level of understanding. "I said an enthusiastic "Thank you, sir!" and sat back down, whereupon he immediately went back to the lesson at hand, while I pondered everything that exchange revealed to my budding mind. Questions of how a transformer could pass the waveform unmolested, how a 3-phase transformer might be made differently... how even modern electric motors were almost all 3-phase motors, and the run capacitor just simulated the 3rd phase all fell into place. It was a "That's good; you've just taken your first step into a larger world." moment for me.

I don't think I've ever had a single teacher (except maybe one math teacher who actually made quadratic equations accessible to my mechanical mind) who taught me as much as he did.



mnem
*toddles off to ded*

A good inspiring teacher is what every teacher should stride to become. A countries future prosperity will in the large part hinge around the standard of teaching. Yet so often we find the education system being starved of investment and the standards drop as a result? I'm glad that you and I both found certain teachers that could inspire us.

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[tggzzz]

Is it normal for the trace to be so thick (is that what you call it)? I'm an SA noob and this one being a used machine of unknown history doesn't help with knowing what to expect as normal. The cal signal looks reasonable to me.

Next question is how to best test out the bandwidth of the scope probes since I don't have those probe-to-bnc adapters.

Be very careful about the SA input; compared with scopes the input is relatively vulnerable w.r.t. DC and power. With a noise souce, don't forget that the relevant power is integral of all the powers at all the frequencies - so a -30dBm trace isn't as "safe" as you might think.

You are looking at a noise source, so unsurprisingly the trace looks noisy. Play around and understand the effects of "video bandwidth", "resolution bandwidth" and "trace averaging".

Connecting a scope probe. Don't forget the SA has a 50ohm input, so a standard "high" impedance probe can't be connected to the input. OTOH a "low" impedance Z0 resistive divider probe is fine.

If you want to measure the response of a probe, then you should use whatever connection mechanism you will be using in the real circuit, including a 6" ground lead (if you must!). The best results will be obtained with the standard short bent spring wire slipped over the probe's ground, or similar.

[tggzzz]

Couldn't resist an HP 6296a - in not bad shape - ended up for $ AUD 73, 60V 3A. Down-under prices are pretty high.

My one nasty connection with the national grid (230v) unfortunately gripped my hand onto the DUT and the power - only way I could let it go was to throw the whole assembly (an amp) across the room, the connection point burnt into my left thumb about 3mm, I still have the scar. I have a lot of respect for anything over 60V. Earthing, earth leakage detection, a foot operated 'dead man pedal' (ie take your foot off and the circuit de-powers) are now essential in my book.

What, you had no earth leakage detection at all? [emoji53] Well I sincerely hope that others reading this will now, like you, be getting themselves that level of protection.

Sent from my POT-LX1 using Tapatalk

When I touched 240Vac live with one hand and neutral with another it was ~1973, so domestic breakers were unknown. Fortunately the involuntary contraction of my biceps broke the circuit.

Sent from my desktop using GropeARodent.

[Specmaster]

And now for just shits and giggles here's something completely different

https://www.youtube.com/watch?v=J1FfrnOXGHg&feature=youtu.be&fbclid=IwAR3CAtPCMCzuxcg3R1zAJDA7BK37YV52Aiy0TCSH8fUi9E1Ip98S0B5nhrg

[bd139]

The irony of that sketch is Cleese has turned into one of them...

[VK5RC]

Couldn't resist an HP 6296a - in not bad shape - ended up for $ AUD 73, 60V 3A. Down-under prices are pretty high.

My one nasty connection with the national grid (230v) unfortunately gripped my hand onto the DUT and the power - only way I could let it go was to throw the whole assembly (an amp) across the room, the connection point burnt into my left thumb about 3mm, I still have the scar. I have a lot of respect for anything over 60V. Earthing, earth leakage detection, a foot operated 'dead man pedal' (ie take your foot off and the circuit de-powers) are now essential in my book.

What, you had no earth leakage detection at all? [emoji53] Well I sincerely hope that others reading this will now, like you, be getting themselves that level of protection.

Sent from my POT-LX1 using Tapatalk

I should have said it was 45yrs ago, I don't think
earth leakage detectors  were common in those days. We definitely didn't have one at that time.
Rob

[Specmaster]

Anybody in UK near London ? https://www.eevblog.com/forum/buysellwanted/moving-house-free-gear/

Thanks for the heads up, my PM is in already, fingers crossed.

Update, Howard says that there others who got their request in first but if they fall though he'll let me know so it's not looking too hopeful at the moment. If however I'm lucky there are bits that I don't really need or have the space so if I do happen to get lucky and there's anything that anybody would like, let me know and we maybe be able to work something out, but first lets see what happens.

[med6753]

Unless the code has changed recently "whole house" RCD protection, or what we call GFI, is not required. What IS required is RCD protection for all outlets in kitchens and baths. That's accomplished by having an RCD outlet at the beginning of the string so all outlets after it are protected. RCD breakers are available in 15 and 20 amp sizes and can be used for whole circuit protection and in some cases are required such as the circuit for an outdoor swimming pool or all circuits in a garage. It really depends on the application.

But a typical bedroom/living room usually is not RCD protected.   

[Cerebus]

@specmaster: I might take you up on that if you're successful.

Truthfully I'd have liked to cart off the whole lot, but space (in a relatively small terraced London maisonette) tends to keep my acquisitiveness in check. I'd quite like a crack at fixing and using that DC load. Heck, i'd like all those analogue scopes but the space versus "use it will get" factor for analogue scopes mean I'm holding out until I find a nice example of something high bandwidth and relatively compact, say a Tek 2465x. I also could do with a decent 10MHz reference, but that Racal monster is just too many m³/ppb for me.

[med6753]

You Brits and your unique terms. I had to look up "maisonette". That term is unknown here, or at least I never heard of it. And guess what? I live in one! Holy shit!  The next time someone asks about where I live I'll tell them in a maisonette and watch the puzzled looks. 

[Cerebus]

Unless the code has changed recently "whole house" RCD protection, or what we call GFI, is not required.

RCD protection for all supplies at the distribution board is now the norm for UK installations, either new installations or ones modified in (from memory) the last fifteen years. Either an overall RCD + breakers for individual circuits, or an RCBO (combined RCD + breaker) for individual circuits. My place has  an RCD + three breakers for lighting, an RCD + several breakers for wall outlets and a 40A cooker supply, and an RCBO for the supply to the loft (potentially an area with water related faults and I thought it a good idea to have a local supply that could trip without tripping the whole supply).

[Cerebus]

You Brits and your unique terms. I had to look up "maisonette". That term is unknown here, or at least I never heard of it. And guess what? I live in one! Holy shit!  The next time someone asks about where I live I'll tell them in a maisonette and watch the puzzled looks. 

For the querulous - Maisonette: a flat or apartment with its own (street level) entrance, from the French diminutive for 'house'. I'll bet your lot don't have bungalows either, or verandas.

[med6753]

You Brits and your unique terms. I had to look up "maisonette". That term is unknown here, or at least I never heard of it. And guess what? I live in one! Holy shit!  The next time someone asks about where I live I'll tell them in a maisonette and watch the puzzled looks. 

For the querulous - Maisonette: a flat or apartment with its own (street level) entrance, from the French diminutive for 'house'. I'll bet your lot don't have bungalows either.

Yes, we do have bungalows.

[med6753]

Unless the code has changed recently "whole house" RCD protection, or what we call GFI, is not required.

RCD protection for all supplies at the distribution board is now the norm for UK installations, either new installations or ones modified in (from memory) the last fifteen years. Either an overall RCD + breakers for individual circuits, or an RCBO (combined RCD + breaker) for individual circuits. My place has  an RCD + three breakers for lighting, an RCD + several breakers for wall outlets and a 40A cooker supply, and an RCBO for the supply to the loft (potentially an area with water related faults and I thought it a good idea to have a local supply that could trip without tripping the whole supply).

Conversely here is how my place is set up. In the breaker box: One 100 amp main and 9 circuit breakers. 7 - 15 amp breakers for general lighting/outlets and 2 - 20 amp breakers each supplying one outlet in the bedroom and one in the living room intended for window A/C units. No RCD's. The bath has one outlet which is an RCD outlet. The kitchen has 3 outlets in which one is an RCD outlet and the other two are protected by it. 

[tggzzz]

You Brits and your unique terms. I had to look up "maisonette". That term is unknown here, or at least I never heard of it. And guess what? I live in one! Holy shit!  The next time someone asks about where I live I'll tell them in a maisonette and watch the puzzled looks. 

For the querulous - Maisonette: a flat or apartment with its own (street level) entrance, from the French diminutive for 'house'. I'll bet your lot don't have bungalows either, or verandas.

That definition matches a house.

I've always thought, possibly incorrectly, that a maisonette was a two story dwelling somewhere in a skyscraper. So it is more-or-less a "flat" with an internal private staircase, and the "street level" might be a "street in the sky".

[tggzzz]

You Brits and your unique terms. I had to look up "maisonette". That term is unknown here, or at least I never heard of it. And guess what? I live in one! Holy shit!  The next time someone asks about where I live I'll tell them in a maisonette and watch the puzzled looks. 

The term "condominium" is unknown here.

[Cerebus]

I've always thought, possibly incorrectly, that a maisonette was a two story dwelling somewhere in a skyscraper. So it is more-or-less a "flat" with an internal private staircase, and the "street level" might be a "street in the sky".

That description would fit, I believe - but am more than open to correction, what our North American cousins would call a 'duplex' in a 'condo' - both terms unheard outside the continent of North America.

Maisonette is almost always used (around these parts anyway) to refer to low-rise buildings. Go beyond two dwellings in one (vertical) building and I'd start talking about a 'block of flats' or a 'flatblock' as some would have it. Maisonette might stretch to more dwellings in some of the older London houses that have been retrospectively converted into upper flats that share a street level entrance and a basement flat with it's own entrance. I think the essence of 'maisonette' is that the envelope of the building ought to fit the idea of 'house' in that locale.

[Cerebus]

Veering further off track, I can't nowadays hear the words "bungalow" or "veranda" without hearing in my head Sanjeev Bhaskar's voice saying "Indian!". For the benefit of those who have been deprived this treat, a sample of "Goodness gracious me" from the TV in the 90s:

[VK5RC]

In South Australia a "maisonette" is a single building that has two dwellings - separate entrances - separate often separate small gardens - only a common wall or so. The common wall has to extend to or above the roof line for fire isolation.

[Specmaster]

Unless the code has changed recently "whole house" RCD protection, or what we call GFI, is not required. What IS required is RCD protection for all outlets in kitchens and baths. That's accomplished by having an RCD outlet at the beginning of the string so all outlets after it are protected. RCD breakers are available in 15 and 20 amp sizes and can be used for whole circuit protection and in some cases are required such as the circuit for an outdoor swimming pool or all circuits in a garage. It really depends on the application.

But a typical bedroom/living room usually is not RCD protected.   

Over here, on this side of the pond they changed it say any socket that may be used to supply power to anything outside of the equipotential zone must be protected so we tend to cover the entire house.

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