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
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.
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
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.pdfReally 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 VishaySo 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.
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.
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
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
Quote from: BU508AIncoming 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.Quote from: BU508AWill 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
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.
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.
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
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?![]()
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
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
You are not wrong, it used to be a 221AHowever, 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.
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 !