Test Equipment Anonymous (TEA) group therapy thread

[Neomys Sapiens]

The 3 leg tant's are made for low impedance, not being reversable. Unless it has more then 25V DC on it I'd let it stay where it is.

Oh OK, thanks. Don't understand though why they don't just put two regular 2-leggeds ones in parallel then ?
3 legged on is a tiny bit more compact, but it's not an issue on that particular board.

It's for installation, not impedance. If you wanted impedance you'd use a tant and ceramic in parallel.

Specs are same as the two legged ones.

Says so on the datasheet! https://www.vishay.com/docs/40044/299d.pdf



Really this is about making them even more of a bastard to get out of a board 

Evil becomes easy to discern when it comes with three legs!

[xrunner]

I don't have the schematic, but if you are sure that they use a non-polarized one for "safety" but the schematics actually does not REQUIRE one for the proper operation ot the unit... well yes of course in this case you can do as you please and replace it with a 2 legged one of same value...

That said, I don't even know if you could replace it with a 3 legged one... I mean are these things still available these days ?!

I guess in the short term, for now best not to touch it if it tests good. Restore the unit first and then when it all works, worry about replacing the tantalum as preventative maintenance since sooner or later it will fail. But why bother replacing it if you don't even know if the unit can be fixed...

Really this is about making them even more of a bastard to get out of a board 

Oh I don't know, those three leads form quite a useful little fin which will help stabilise its trajectory when it ultimately explodes and comes winging off the board. 

Damn this thread moves fast!

OK great, thanks for all the input, good to know. The schematic is attached (C10). Doesn't show any additional information from just that other than it's a cap.

So for now "Let sleeping dogs lie" 

[Ice-Tea]

I sold a few R&S APN62's over the last few months. Every single one of them went pop when plugged in and to noones surprise, it turned out to be Schaeffner/RIFA inside. The last one I plugged in didn't "go", though. I didn't think much of it but decided to replace it anyways because, well, I'm not that Ferengi.

Imagine my surprise to learn it wasn't Schaeffner inside. I never even considered the possibility because *all* linefilters like this I've ever seen were Schaeffner. I feel slightly sick now, it feels like the earth is sinking beneath my feet 

[tggzzz]

Talking of OXCO's I've been putting one of my HP 10811Ds into a case and fired it up for the first time on Tuesday. Frequency was fine with No EFC and the mechanical trimmer untouched since it was removed ftom a 8922 cell test set abou 4 years ago and has been in a storae container for at least a couple of years the error to GPS was 0.052Hz.
Overall I'm pretty pleased. I made one difficult decision to use a DC-DC converter so it can run off mains or 9-18V DC. I'm seeing a little bit of nise from the DC-DC on the output. It goes up with the oven current and appears to be short bursts of noise.

I went overboard with mine: capacitance multiplier, 723 regulator (since the diode is low noise), and ferrites/caps. I may be able to provide a screenshot later

Screenshots using a Tek 492AP (red) and HP8562B (green). Note the different horizontal scales, but both are 3Hz VBW and 100Hz RBW.

IIRC the capacitance multiplier feeds both the oven and 723, the 723 feeds the oscillator only. The case is diecast ali, and the PSU is an external linear supply.

[factory]

In the downtime I didn't get to post the final part of the Ericsson counter repair, I'm back at work now so not been able to play with TEA much at the moment and can't view the forum using my mobile at work as my provider (three) decided it wants to rip-off PAYG customers same as most other providers already do, 5p a Mb FFS. 

New purchases from the wallet draining auction site are;
A Wayne Kerr B900 LCR bridge, sellers pictures are low res so here are the details from Wireless World March 1975, hopefully should be here soon as it's been dispatched.


The option 001 (variable audio oscillator) for my hp 8640B with attached carcass from Germany, didn't win the 5360A that I was bidding for from the same seller, someone advertised it here but no idea if that helped raise the price. 


And another random purchase this morning of some Racal crystal ovens which are probably knackered, didn't get a chance to check the part numbers this morning before going to work, but I think they should fit.

David

[mnementh]

The 3 leg tant's are made for low impedance, not being reversable. Unless it has more then 25V DC on it I'd let it stay where it is.

Oh OK, thanks. Don't understand though why they don't just put two regular 2-leggeds ones in parallel then ?
3 legged on is a tiny bit more compact, but it's not an issue on that particular board.

It's for installation, not impedance. If you wanted impedance you'd use a tant and ceramic in parallel.

Specs are same as the two legged ones.

Says so on the datasheet! https://www.vishay.com/docs/40044/299d.pdf

   Really this is about making them even more of a bastard to get out of a board 

Ah great, thanks for that datasheet ! Final word it is then, it looks...  I will tend to trust Vishay     So it's indeed just for convenience and nothing else...

Oh I don't know, those three leads form quite a useful little fin which will help stabilise its trajectory when it ultimately explodes and comes winging off the board. 

Except... IME, the legs are usually the only thing left when the cap blows off the board and pings past your ear... 

mnem
...and you taste the smoke for days afterwards... 

[Ice-Tea]

Talking of OXCO's I've been putting one of my HP 10811Ds into a case and fired it up for the first time on Tuesday. Frequency was fine with No EFC and the mechanical trimmer untouched since it was removed ftom a 8922 cell test set abou 4 years ago and has been in a storae container for at least a couple of years the error to GPS was 0.052Hz.
Overall I'm pretty pleased. I made one difficult decision to use a DC-DC converter so it can run off mains or 9-18V DC. I'm seeing a little bit of nise from the DC-DC on the output. It goes up with the oven current and appears to be short bursts of noise. It's good enough as a frequency reference but not to multiply up to microwavs frequencies. I'll have to do a bit of work and see if I can knock it down a bit further.

Aye, there's the rub. Now I'm mucking about with building frequency standards I'm beginning to feel I need an SA.

Woe is me, it just looks like I'll have to start looking for one. 

I have a Marconi TF2370 available to a good home. Only 110MHz but digital storage and 5Hz resolution bandwidth make it better than a lot o SAs for looking at close in noise.

Tempting, and truthfully it would probably be a technically good fit for things I might practically need to do. But:



The bulk of that boat anchor would exceed both my available space and what little remaining store of WAF I have available to me. 

Have had one here for over a year. Never have been able to run it as I don't have the connecting cables On the long list of "things to check". 

[Vince]

See my followup post.    https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg3544804/#msg3544804

That situation is precisely when you need something like the light blub tree, so you can add blubs to increase the max current. Doing so in smallish increments is your best means of successfully getting to a full-power state without having to replace the switcher transistor like half a dozen times.

Some SMPS can actually be powered from a CC/CV DC power supply... but ones which can provide adequate voltage and inrush current are expensive, and still oscillation can be very destructive on both the DUT and PSU.

I've learned this the hard way several times over the years, in several seemingly different scenarios. Sometimes the simpler tools simply are better.

mnem
 

Ah, so you mean the dim bulb tester is not inherently inadequate for an SMPS... and mine was blinking just because I had not enough wattage (single 100W bulb from memory... was 4 years ago...). Fine fine fine....

[mansaxel]

What was I saying about using "the cloud" for everthing last week....

The cloud would have survived this. This would have been an "availability zone failure" which is easy to architect around. In fact I spent a week about 2 weeks ago actually just pulling plugs metaphorically speaking with no side effects at this level.

What happened here is "lowest bidding hoster had a massive shit show" not "the cloud".

And just remember that the guys running the "lowest bidding hoster" know more than the average person.

Your stuff is safer in the cloud. If you do it properly.

And the data security argument is void. What you post on a public forum is public. What you post in a private S3 bucket in AWS is not.

Edit: I notice the forum is running like shit now as well. Another problem easily resolved by upping the instance size transparently rather than buying another physical machine 

Confession: I view the cloud as job security; there's going to be a non-ending capacity need for networking to the Internet. 

Other than that, I'm generally against the cloud -- specifically more so the cloud model where someone else is the application administrator and less so the model where one just rents capacity. In the latter case, if you hit a sweet spot where you don't consume much CPU (and doubly so GPU), not transfer lots of data, and mostly idle, the cloud can be a big saving compared to own iron. As soon as you have substantial, and preferably predictable, needs of data transfer, computation power and such, own iron becomes much more interesting.

Finally, what bd139 writes about doing the homework wrt availability is extremely true.  On your own iron, you can prioritise and get back after a fire by buying your staff pizza (providing you have backups et c). Amazon does not accept pizza as skip-forward-in-restore-queue tokens, so you're on your own. Better have an exit plan. And a contingency plan with some seriousness in.

Finally: If you build things just right, you can survive this even if you're on OVH and that Ogden site. The weeks between Strasbourg and Ogden fires should, in that case, have been spent trigging the plans for a third and fourth redundancy site. With haste.

[factory]

Incoming DL1200A here by next week. 

Hmmm... are you a Yokiogawa lover, collecting them ?!

They aren't very common in France at the very least. Never everheard about them in my entire live. I became aware of them only recently as I was searching the local ads fr the keyword "oscilloscope"... a Yokogawa popped up, wondered what the hell that was. Looked like some medical gear or something...  was curious to play with one but it was not to be, since the sellers wanted a delirious amount of money given the poor specs of the scope.

Will do then a teardown of it.

Would be curious to see that. When you do, please post a link to it here, so I don't miss it 

They aren't particularly common here either, I wouldn't have known much about them if we hadn't had one at work.
OK the specs aren't great but they were more than enough for working on the train parts we repaired at work. Also it doesn't take too much horizontal bench space, which was in short supply at work and is at home too.
The built in printer got used all the time at work, but the floppy drive had failed, I preferred the user interface to the digital Tek's we had at work (more buttons & less annoying menus), but others may disagree.
Note: service information for Yokogawa stuff is not easy to get.

David

[factory]

Talking of OXCO's I've been putting one of my HP 10811Ds into a case and fired it up for the first time on Tuesday. Frequency was fine with No EFC and the mechanical trimmer untouched since it was removed ftom a 8922 cell test set abou 4 years ago and has been in a storae container for at least a couple of years the error to GPS was 0.052Hz.
Overall I'm pretty pleased. I made one difficult decision to use a DC-DC converter so it can run off mains or 9-18V DC. I'm seeing a little bit of nise from the DC-DC on the output. It goes up with the oven current and appears to be short bursts of noise. It's good enough as a frequency reference but not to multiply up to microwavs frequencies. I'll have to do a bit of work and see if I can knock it down a bit further.

Almost looks like the case was once from a hp 220/221A, I hope I'm wrong.


David

[bd139]

What was I saying about using "the cloud" for everthing last week....

The cloud would have survived this. This would have been an "availability zone failure" which is easy to architect around. In fact I spent a week about 2 weeks ago actually just pulling plugs metaphorically speaking with no side effects at this level.

What happened here is "lowest bidding hoster had a massive shit show" not "the cloud".

And just remember that the guys running the "lowest bidding hoster" know more than the average person.

Your stuff is safer in the cloud. If you do it properly.

And the data security argument is void. What you post on a public forum is public. What you post in a private S3 bucket in AWS is not.

Edit: I notice the forum is running like shit now as well. Another problem easily resolved by upping the instance size transparently rather than buying another physical machine 

Confession: I view the cloud as job security; there's going to be a non-ending capacity need for networking to the Internet. 

Other than that, I'm generally against the cloud -- specifically more so the cloud model where someone else is the application administrator and less so the model where one just rents capacity. In the latter case, if you hit a sweet spot where you don't consume much CPU (and doubly so GPU), not transfer lots of data, and mostly idle, the cloud can be a big saving compared to own iron. As soon as you have substantial, and preferably predictable, needs of data transfer, computation power and such, own iron becomes much more interesting.

Finally, what bd139 writes about doing the homework wrt availability is extremely true.  On your own iron, you can prioritise and get back after a fire by buying your staff pizza (providing you have backups et c). Amazon does not accept pizza as skip-forward-in-restore-queue tokens, so you're on your own. Better have an exit plan. And a contingency plan with some seriousness in.

Finally: If you build things just right, you can survive this even if you're on OVH and that Ogden site. The weeks between Strasbourg and Ogden fires should, in that case, have been spent trigging the plans for a third and fourth redundancy site. With haste.

Some of it is job security yes but the majority of it is about reducing capital expenditure particularly on hardware cycles and reducing cost by pooling administrative resources by the cloud provider. It’s also a much easier way of hiring two racks in distinct DCs and taking the overhead of arguing with VRRP, peering and private links to get redundancy. I have lost count of how many sales meetings I’ve sat through with Cisco, Juniper, HPE and F5. And nothing works reliably with CM tooling. All those vendors are gone.

Another key thing is we can bring up a whole isolated DC class environment in 30 minutes. We have 22 VPCs at the moment as isolation. That gets pretty damn expensive quickly in hardware even with virtualisation.

You can pay to get to the front of the queue at Amazon. We did. I regularly talk to their product level architects and administrators.

I loved hardware but I can’t in my position sell someone that as a solution any more. Doesn’t add up for anything other than niche cases.

[kleiner Rainer]

More from Dads basement:

The Easter weekend was a good time to visit the parents and help Mum clean out unnecessary stuff. Rummaging around in the basement I found this:



Nice "Luftwaffe" grey, and the lettering looks hand made with black ink, protected by a layer of clear lacquer.

Dad built it during his stay at the "Technische Schule der Luftwaffe 1"* in Kaufbeuren at the end of the fifties. You guess it: its a tester for the then new Germanium- and Silicon-based transistors. On the outside its a bit dusty after 60 years, but on the inside it is still clean:



The meter is a Weston sealed and ruggedized 1mA MIL job, the knobs are real US made chickenhead knobs, and after a bit of cleaning I powered it with a lab power supply and it still works. Even the test leads are still there:



Sadly, the battery holders and one knob are missing, so some creativity is needed to restore it to its full glory. Maybe further sorting through the basement will be required...

More finds included NOS 12AX7 in original NATO packaging, made by Valvo in 1961 and some nice hermetically sealed mylar caps (.22Mfd, 50V, 1%).  Some nice Easter eggs, I would say.

Greetings,

Rainer

* avionics school of the federal german airforce

[bd139]

Tek P6042 kit, £35 about 40 minutes from me. Do I or don't I. I'm probably not going to use it if I get it TBH.

[med6753]

You guys are a bad influence. All this talk of crystal oscillators/references persuaded me to put my hp hat on and at great risk to my hernia pulled out the 5248L and the reference and fired it up. Now it may not be as accurate or as stable as your play toys but it's got Nixies. Who doesn't like Nixies?   

[bd139]

Ok OCXO all done and installed.



Link to repo with documentation, BOM, gerbers and stuff is on the picture

This is about the first time I've put something together and it worked first time 

[xrunner]

Damn nice job. 

[Specmaster]

@bd139, really nice job, and if it wasn't for the colour, you'd be hard-pressed to tell that it wasn't original 

[Robert763]

The 3 leg tant's are made for low impedance, not being reversable. Unless it has more then 25V DC on it I'd let it stay where it is.

Oh OK, thanks. Don't understand though why they don't just put two regular 2-leggeds ones in parallel then ?
3 legged on is a tiny bit more compact, but it's not an issue on that particular board.

It's for installation, not impedance. If you wanted impedance you'd use a tant and ceramic in parallel.

Specs are same as the two legged ones.

Says so on the datasheet! https://www.vishay.com/docs/40044/299d.pdf



Really this is about making them even more of a bastard to get out of a board 

Well I stand corrected. I have only ever seen these used on boards that also had conventional tantalums. The 3 legged ones were in locations that appeared to be EMI/EMC critical. This was on boards from two different OEMs and both had more conventional tants than 3 legged.
Clearly they were marketed for reversability (but not bipolar) but equally clear is that they will also have lower installed series inductance than a two legged one. Thus designers may have selected them for that. Only the designer knows for sure.
With RF it is not uncommon to test specific components of the same nominal value for their specif high frequency properties.
 

[Vince]

You guys are a bad influence. All this talk of crystal oscillators/references persuaded me to put my hp hat on and at great risk to my hernia pulled out the 5248L and the reference and fired it up. Now it may not be as accurate or as stable as your play toys but it's got Nixies. Who doesn't like Nixies?   

Wow.... that's some serious bit of kit  !  Love these old HP counters of that generation, indeed they look so cool with all those nixies ! And that rugged industrially looking face, love it. They are definitely on my wish list, but sadly nowhere to be found in France. Would need to import one from the US.. big bucks involved. So just a dream for now.

Best I could get some time ago, was my super rare Metrix DX446A.  8 nixes like yours, 160MHz which is quite good for the time I find.. but sadly of course its industrial design is nowhere near as cool / military looking as these old HP...
Still, a nice rare piece so I enjoy it very much. Sadly the previous owner lost one of the knobs and replaced it with this ugly and out of place red knob  from a FERISOL branded counter I think. So ugly that it kinda ruins my lovely experience with this counter. So I have since removed that knob altogether. I prefer a bare shaft (it's not stiff, I can still operate that shaft without a knob) than seeing that disgusting knob.  Sadly I will never find an original knob for it, forget about it 

Anyway, looks like this outage was a good thing. Somehow since that happened, TEA is now back about cool TEA content, what I came for... may it continue ! 

[Robert763]

Talking of OXCO's I've been putting one of my HP 10811Ds into a case and fired it up for the first time on Tuesday. Frequency was fine with No EFC and the mechanical trimmer untouched since it was removed ftom a 8922 cell test set abou 4 years ago and has been in a storae container for at least a couple of years the error to GPS was 0.052Hz.
Overall I'm pretty pleased. I made one difficult decision to use a DC-DC converter so it can run off mains or 9-18V DC. I'm seeing a little bit of nise from the DC-DC on the output. It goes up with the oven current and appears to be short bursts of noise. It's good enough as a frequency reference but not to multiply up to microwavs frequencies. I'll have to do a bit of work and see if I can knock it down a bit further.

Almost looks like the case was once from a hp 220/221A, I hope I'm wrong.


David

You are not wrong, it used to be a 221A    However, in my defence, It was one of two that I rescued from from being scrapped. That one had very worn controls and switches. It was always tempermental and last time I powered it on it let the magic smoke out 
The second one was repaired and is used everyso often but they are not a great generator, completly uncalibrated.
 

[xrunner]

Sadly the previous owner lost one of the knobs and replaced it with this ugly and out of place red knob  from a FERISOL branded counter I think. So ugly that it kinda ruins my lovely experience with this counter. So I have since removed that knob altogether. I prefer a bare shaft (it's not stiff, I can still operate that shaft without a knob) than seeing that disgusting knob.  Sadly I will never find an original knob for it, forget about it 

That's a neat TEA item Vince. On the knob, I've had some luck reproducing some knobs with a 3D printer and Fusion 360. Most recently for a Yaesu FRG-7000 shortwave RX that some yay-hoo substituted knobs on. Old original knobs are not to be found.

But, that's another rabbit hole you might want to investigate eventually ... or not ... 

[bd139]

You are not wrong, it used to be a 221A    However, in my defence, It was one of two that I rescued from from being scrapped. That one had very worn controls and switches. It was always tempermental and last time I powered it on it let the magic smoke out 
The second one was repaired and is used everyso often but they are not a great generator, completly uncalibrated.

Letting the smoke out is a feature of HP generators around that era. Also gratuitous annoying use of tunnel diodes and unobtainium hybrid ASICs

[factory]

You guys are a bad influence. All this talk of crystal oscillators/references persuaded me to put my hp hat on and at great risk to my hernia pulled out the 5248L and the reference and fired it up. Now it may not be as accurate or as stable as your play toys but it's got Nixies. Who doesn't like Nixies?   

Wow.... that's some serious bit of kit  !  Love these old HP counters of that generation, indeed they look so cool with all those nixies ! And that rugged industrially looking face, love it. They are definitely on my wish list, but sadly nowhere to be found in France. Would need to import one from the US.. big bucks involved. So just a dream for now.

Best I could get some time ago, was my super rare Metrix DX446A.  8 nixes like yours, 160MHz which is quite good for the time I find.. but sadly of course its industrial design is nowhere near as cool / military looking as these old HP...
Still, a nice rare piece so I enjoy it very much. Sadly the previous owner lost one of the knobs and replaced it with this ugly and out of place red knob  from a FERISOL branded counter I think. So ugly that it kinda ruins my lovely experience with this counter. So I have since removed that knob altogether. I prefer a bare shaft (it's not stiff, I can still operate that shaft without a knob) than seeing that disgusting knob.  Sadly I will never find an original knob for it, forget about it 

Anyway, looks like this outage was a good thing. Somehow since that happened, TEA is now back about cool TEA content, what I came for... may it continue ! 

Expand your ePay search to the rest of Europe & you should find HP stuff appear occasionally, no need to import from the US unless it's something uncommon.

I'm sure someone on here will recognise the brand of knobs used on the FERISOL counter.

David

[nixiefreqq]

don't be a knob snob.

put the red one back on until something better comes along.

"if you can't be with one you love......love the one you're with"