Test Equipment Anonymous (TEA) group therapy thread

[med6753]

Ok putting curve tracer project away for a few weeks. My attempts to build a suitably powerful ramp generator with 100v compliance are not going well. I need to scale it up to 500v. So I can do 60v fine but anything above that seems to break out into wild oscillation if I load it with more than a few mA. What’s even worse is the oscillation lasts a couple of cycles and then ends the pass BJT rather spectacularly which isn’t enough time to suss what’s going on even with the SDS1202X-E on the case.

Electroboom moment? 

I was just gonna say. Deja vu......another project goes up in flames. 

Edit...yep....smoke ring of death. 

[bd139]

It’s no fun if fire doesn’t come out at least once.

Interesting read. Fucking hams  : https://www.arcadiapublishing.com/Navigation/Community/Arcadia-and-THP-Blog/April-2018/How-Amateur-Radio-Sunk-the-Titanic

[tggzzz]

Ok putting curve tracer project away for a few weeks. My attempts to build a suitably powerful ramp generator with 100v compliance are not going well. I need to scale it up to 500v. So I can do 60v fine but anything above that seems to break out into wild oscillation if I load it with more than a few mA. What’s even worse is the oscillation lasts a couple of cycles and then ends the pass BJT rather spectacularly which isn’t enough time to suss what’s going on even with the SDS1202X-E on the case.

You could always just use an opamp. Yes, at least one has supply voltages up to 900V But 100V ones are more common.

[med6753]

It’s no fun if fire doesn’t come out at least once.

Interesting read. Fucking hams  : https://www.arcadiapublishing.com/Navigation/Community/Arcadia-and-THP-Blog/April-2018/How-Amateur-Radio-Sunk-the-Titanic

Well when the Type 561B went snap, crackle, pop a few months back it quite frankly scared the crap out of me. It had been quite a few years since my last bang. That was a tant in a 465.

Not surprising about the radio communications Fubar on the Titanic. Wide band spark gap transmitters and no regulation. What could go wrong?   

[bd139]

Ok putting curve tracer project away for a few weeks. My attempts to build a suitably powerful ramp generator with 100v compliance are not going well. I need to scale it up to 500v. So I can do 60v fine but anything above that seems to break out into wild oscillation if I load it with more than a few mA. What’s even worse is the oscillation lasts a couple of cycles and then ends the pass BJT rather spectacularly which isn’t enough time to suss what’s going on even with the SDS1202X-E on the case.

You could always just use an opamp. Yes, at least one has supply voltages up to 900V But 100V ones are more common.

Too expensive. Already looked. This is a design that needs to be reproducible and attainable by anyone as I’m going to open source it if I finish it. I am investigating TV scan circuits now as they have some common requirements regarding compliance, frequency and linearity.

[tggzzz]

Ok putting curve tracer project away for a few weeks. My attempts to build a suitably powerful ramp generator with 100v compliance are not going well. I need to scale it up to 500v. So I can do 60v fine but anything above that seems to break out into wild oscillation if I load it with more than a few mA. What’s even worse is the oscillation lasts a couple of cycles and then ends the pass BJT rather spectacularly which isn’t enough time to suss what’s going on even with the SDS1202X-E on the case.

You could always just use an opamp. Yes, at least one has supply voltages up to 900V But 100V ones are more common.

Too expensive. Already looked. This is a design that needs to be reproducible and attainable by anyone as I’m going to open source it if I finish it. I am investigating TV scan circuits now as they have some common requirements regarding compliance, frequency and linearity.

Indeed

You might be able to use a voltage multiplier with a controlled/variable voltage input, or the usual opamp PSU bootstrap circuits (being careful about power up/down), or "research" some ideas from Fluke/Datron 1kV calibrators.

[Specmaster]

It’s no fun if fire doesn’t come out at least once.

Interesting read. Fucking hams  : https://www.arcadiapublishing.com/Navigation/Community/Arcadia-and-THP-Blog/April-2018/How-Amateur-Radio-Sunk-the-Titanic

And there was I thinking that it was sunk by an iceberg geez 

On a serious note, I can understand how that situation came about between the rival companies and also the warnings of icebergs in the area as well. I mean there was all the previous hype about the Titanic being unsinkable, so the radio operators believed they were invincible 

[mnementh]

Urrgh. Spent all day trying to find the parts for my 4070A from a CA warehouse... ANY CA warehouse... eventually gave up and paid the moosefucker tax; ordered it from DigiKey. 

Now facing exactly the same fucking headache, only it's the keyboard on my Lenovo Flex-3... which, joy of joys, uses the same keyboard as the Yoga (incorporated into the top cover) so it costs a fucking fortune, even from Shanghai. Or Shenzhen. Or Hong Kong... you get the drift.

mnem

Moosefucker tax? Eh?     Hoser!   

Yeah... that's the tax you pay for daring to move across the border. A few dollars at every step of the transaction; it all adds up. Makes what shoulda been a $28 order a $55 order.

And no choice about where to order from, so... 

My spirit animal is attached.

mnem

[Brumby]

Moosefucker tax? Eh?     Hoser!   

Yeah... that's the tax you pay for daring to move across the border. A few dollars at every step of the transaction; it all adds up. Makes what shoulda been a $28 order a $55 order.

And no choice about where to order from, so... 

My spirit animal is attached.

mnem

That sounds like the Downunder tax.

[Kosmic]

Well, I decided to do like everybody and bought a NanoVNA 

(SNIP)   

Conclusion, it's working relatively well on the nF range. And it's really interesting to see the capacitance changing over frequency. When you reach 1uF the frequency is too high and the result are not super accurate. I also tried in the pF range but I think my calibration setup is failing me and it was not super conclusive.

Looks exactly like the kit I ordered from Bang-em-good. Even down to the crooked N-connectors... 

I went with bg because they offered a fair price, and I had some affiliate points to burn; brought total cost of that and the Tiny SA down to (goes and looks) US$128. Oh yay! They're showing shipped!  I might actually see them by Christmas! 

Hope mine resolves as nicely as yours! 

mnem

It's a really nice piece of kit for the price. Also, if you want improved accuracy, someone actually measured the SAA-2N calibration standards and he is providing the settings for NanoVNA-Saver and the files for Vna-QT (https://www.eevblog.com/forum/testgear/4-inch-display-saa-2n-nanovna-v2-3ghz-with-n-type/msg3284146/#msg3284146).

It seems to me that this won't really help. You need your cal kit characterized, not someone else's. They are unlikely to be exactly the same.

Reference plane is more or less the same on all those calibration standards. Better than using the default value that has nothing to do with the cal standards. In the end, it's a VNA at 80$, it will never be really accurate 

I'll try to do a comparison.

I measured 2 x 18Ghz type N termination. Narda 370 and Inmet 3018.  The blue curve is ideal values of the calibration standards  and the yellowish one is measured values.

The Inmet 3018:


The Narda 370:


Since I don't really have a calibrated VNA to compare to, it's really hard to tell which one is more accurate. Still, on the Narda, the ideal values curve (blue one) give VSWR measurements outside the maximum specs of the termination. So, I tend to believe the measured values of the calibration standards increase accuracy a little bit.

[mnementh]

I've never regretted the money spent on Inmet. Have several of their 18GHz attens in my RC radio toolkit. 

mnem
 

[25 CPS]

Yes!  Yes!  Yes!



Lab cart!  Lab cart!  Lab cart!

As a side note...really like those benches. Where'd you get them?

You raise a good point there.  Shop furniture's an important but frequently overlooked item.  I started out with a crappy bench which is still down in the basement plus a hand-me-down Rubbermaid cabinet that my parents bought but never put together.  I've got a second one I still need to assemble actually.  The shortcomings of that setup were pretty severe so I ended up getting the furniture you saw in that picture over the course of several years.

All of the furniture in that picture is Mastercraft stuff from Canadian Tire that I bought a bit at a time whenever it was on sale.  As much as people including myself knock Canadian Tire, that line of furniture's surprisingly solid and reasonably priced, even more so when it's on sale which they do several times a year.  I just looked at the Canadian Tire website and it looks like most of that furniture's actually for sale right now.

Unfortunately, they occasionally discontinue items.  The four drawer cabinets on top of the large roll around cabinet were discontinued after I bought the first one and it was a bit of an online hunt to find a store that still had stock when I wanted to get the second one.  I got lucky though, a store down the road from my football team's practice field had two left and they were both seriously discounted so after I finished work, I drove out to the east end to the store, bought the cabinet, put it in the back of the truck, doubled back a bit and got suited up for practice.  After football practice, when I got home, it got unloaded and taken out of the packing crate and set up in the workshop.  I think everything else in the picture is still a current product though.

[Kosmic]

No real need for a 432B or C just connect a DMM or DVM module to the connector on the back. This gives the same digital display accuracy (or better) and retains the analogue meter for making adjustments.

Thank you for this, you had me thinking.

I was looking for a way to test those Gigatronics RF Power probe I got recently. Only problem is that I couldn't really find an affordable meter with appropriate cable. So I found some internal pictures and was able to locate where the rectified analog DC output is coming out.



Works perfectly. I was able to test up to 12.4GHz with my sweeper 

[0culus]

Yes!  Yes!  Yes!



Lab cart!  Lab cart!  Lab cart!

As a side note...really like those benches. Where'd you get them?

You raise a good point there.  Shop furniture's an important but frequently overlooked item.  I started out with a crappy bench which is still down in the basement plus a hand-me-down Rubbermaid cabinet that my parents bought but never put together.  I've got a second one I still need to assemble actually.  The shortcomings of that setup were pretty severe so I ended up getting the furniture you saw in that picture over the course of several years.

All of the furniture in that picture is Mastercraft stuff from Canadian Tire that I bought a bit at a time whenever it was on sale.  As much as people including myself knock Canadian Tire, that line of furniture's surprisingly solid and reasonably priced, even more so when it's on sale which they do several times a year.  I just looked at the Canadian Tire website and it looks like most of that furniture's actually for sale right now.

Unfortunately, they occasionally discontinue items.  The four drawer cabinets on top of the large roll around cabinet were discontinued after I bought the first one and it was a bit of an online hunt to find a store that still had stock when I wanted to get the second one.  I got lucky though, a store down the road from my football team's practice field had two left and they were both seriously discounted so after I finished work, I drove out to the east end to the store, bought the cabinet, put it in the back of the truck, doubled back a bit and got suited up for practice.  After football practice, when I got home, it got unloaded and taken out of the packing crate and set up in the workshop.  I think everything else in the picture is still a current product though.

It looks quite nice! I've also thought of equipping my lab with the packing benches that Shahriar of the Signal Path uses.

[Kosmic]

Yes!  Yes!  Yes!



Lab cart!  Lab cart!  Lab cart!

As a side note...really like those benches. Where'd you get them?

You raise a good point there.  Shop furniture's an important but frequently overlooked item.  I started out with a crappy bench which is still down in the basement plus a hand-me-down Rubbermaid cabinet that my parents bought but never put together.  I've got a second one I still need to assemble actually.  The shortcomings of that setup were pretty severe so I ended up getting the furniture you saw in that picture over the course of several years.

All of the furniture in that picture is Mastercraft stuff from Canadian Tire that I bought a bit at a time whenever it was on sale.  As much as people including myself knock Canadian Tire, that line of furniture's surprisingly solid and reasonably priced, even more so when it's on sale which they do several times a year.  I just looked at the Canadian Tire website and it looks like most of that furniture's actually for sale right now.

Unfortunately, they occasionally discontinue items.  The four drawer cabinets on top of the large roll around cabinet were discontinued after I bought the first one and it was a bit of an online hunt to find a store that still had stock when I wanted to get the second one.  I got lucky though, a store down the road from my football team's practice field had two left and they were both seriously discounted so after I finished work, I drove out to the east end to the store, bought the cabinet, put it in the back of the truck, doubled back a bit and got suited up for practice.  After football practice, when I got home, it got unloaded and taken out of the packing crate and set up in the workshop.  I think everything else in the picture is still a current product though.

I bought this one on sale for 150$Can. Frame is solid steel and the top hardwood. It's great. With the 5inch wheels you can move it around easily.

[0culus]

Oh snap...something like that would be an ideal home for the Tek 519 till I can find a proper scope-mobile for it. It's so damn heavy it needs to be on wheels. 

[Kosmic]

Oh snap...something like that would be an ideal home for the Tek 519 till I can find a proper scope-mobile for it. It's so damn heavy it needs to be on wheels. 

You can probably find something similar in the states. Using bing image search I found a lot of similar benchs:

https://www.bing.com/images/search?view=detailV2&insightstoken=bcid_SPBLeKrYbfYB1Rm4M0xCvFBGijmp.....zs*ccid_8Et4qtht&form=SBIVSP&iss=SBIUPLOADGET&sbisrc=ImgPicker&idpbck=1&sbifsz=761+x+706+%c2%b7+22.90+kB+%c2%b7+jpeg&sbifnm=canadiantirebenchonwheels.jpg&thw=761&thh=706&ptime=27&dlen=31268&expw=622&exph=577&selectedindex=0&id=-1878587637&ccid=8Et4qtht&vt=2&sim=11

[med6753]

Oh snap...something like that would be an ideal home for the Tek 519 till I can find a proper scope-mobile for it. It's so damn heavy it needs to be on wheels. 

You can probably find something similar in the states. Using bing image search I found a lot of similar benchs:

https://www.bing.com/images/search?view=detailV2&insightstoken=bcid_SPBLeKrYbfYB1Rm4M0xCvFBGijmp.....zs*ccid_8Et4qtht&form=SBIVSP&iss=SBIUPLOADGET&sbisrc=ImgPicker&idpbck=1&sbifsz=761+x+706+%c2%b7+22.90+kB+%c2%b7+jpeg&sbifnm=canadiantirebenchonwheels.jpg&thw=761&thh=706&ptime=27&dlen=31268&expw=622&exph=577&selectedindex=0&id=-1878587637&ccid=8Et4qtht&vt=2&sim=11

According to Tek Wiki the 519 weighs 99 pounds (45kg). 

Cart you say? Hell.....make one. 



Or in quaint British.......a trolley. 

 

[Kosmic]

The HP 8566B just beside me is 112 pounds 

[med6753]

The HP 8566B just beside me is 112 pounds 

But doesn't the top half and bottom half separate or is it all one piece?

[Kosmic]

The HP 8566B just beside me is 112 pounds 

But doesn't the top half and bottom half separate or is it all one piece?

Yes 2 sections. The RF section is 65lb and the other one 47lb.

[25 CPS]

I bought this one on sale for 150$Can. Frame is solid steel and the top hardwood. It's great. With the 5inch wheels you can move it around easily.

That one’s another one that was hard to find but I picked up one for $150 during the Father’s Day sale a few years ago when I decided to outfit the basement with heavier furniture:





The nice thing about that roll around cart is the bench top height is the same as the 72 inch workbenches so if I’m dealing with heavy stuff, I just need to roll the cart to the bottom of the basement stairs and put whatever heavy object on it, roll it over to the main bench and it’s a horizontal shift off the cart and onto the bench or vice versa for the reverse trip.  The small roll around cabinet is shorter and they designed those so they can slide beneath the 72” workbenches.  Those are on sale right now and I’m thinking about picking up another one.


This is the setup that quickly became unsatisfactory.  The bench itself is flimsy and pretty small.  Right out of the gate the meagre test equipment I had when I moved into this house didn’t fit on it which is why I parked that Rubbermaid cabinet next to it to hold that scope.





It was the day I had to put a Kef Concerto speaker on the bench that the shortcomings with it became totally painfully obvious.  More experiences like that plus a continuously growing complement of test equipment and I outgrew that bench pretty quickly and I had to start doing something about my work area in the basement because it was becoming rapidly unworkable.

[mansaxel]

I rather like Mouser, actually, because they are right next door to me in the tinker dwagon's favorite state.  Shipping is cheap and fast, even with ground options. But paradoxically, I've found that sometimes UPS second day air is actually cheaper than ground with Mouser. I'll take it.

Mouser is free shipping to me with orders above €50 ex VAT. So I batch my orders. If I need something, right now, Elfa has a store 25 km away.

I've got one coming as I type, with caps for the 8060A, new neon for the 6206B, power socket for my Solartron volt meter and a few components needed to test the 6206B, like power resistors.

Edit: Still south of the Mason-Dixon line, but it's out of Texas, in TN now.

[med6753]

I rather like Mouser, actually, because they are right next door to me in the tinker dwagon's favorite state.  Shipping is cheap and fast, even with ground options. But paradoxically, I've found that sometimes UPS second day air is actually cheaper than ground with Mouser. I'll take it.

Mouser is free shipping to me with orders above €50 ex VAT. So I batch my orders. If I need something, right now, Elfa has a store 25 km away.

I've got one coming as I type, with caps for the 8060A, new neon for the 6206B, power socket for my Solartron volt meter and a few components needed to test the 6206B, like power resistors.

Edit: Still south of the Mason-Dixon line, but it's out of Texas, in TN now.

Memphis, TN is the main UPS hub for all air shipping, both domestic and world wide. Your package should go direct from that location.

[med6753]

I bought this one on sale for 150$Can. Frame is solid steel and the top hardwood. It's great. With the 5inch wheels you can move it around easily.

I would not trust putting the 519 on that type of cart. Not because of the weight but because of the height it could present a tipping hazard. My cart at it's highest point is only 25 inches above the floor. Low center of gravity even with the 535A on it. And it's stable with no tendency to tip when moved around.