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MachineGuy
(I’d really like to address you by your real name!)

Thanks for that info from the tin-man.
I can certainly relate to the manufacturer’s published data.
I will take this into consideration the next time I have to select caps.

To address certain points:
1. I am not at all biased against Panasonic caps. They are superb, and I use the EB in Linear audio applications all the time. They are my go-to for that specific application.
2. I also use the Panasonic TSHA and ED/EE Snap-ins as my go-to PSU filter capacitors, with Nichicon GU as my second choice.
3. So, the question arises, WHY do I NOT recommend the EB in THIS Tek PSU application?
4. It is important to understand the function of a cap in each particular place in the circuit. In any PSU application, the AC ripple BETWEEN the Bridge rectifier and the Regulators is enormous. AFTER the regulators, the AC ripple is negligible.
5. A few years ago, to quieten my curiosity, I did a test on an older amplifier using 4 new apparently identical 4700uF 25V and 50V capacitors mounted BETWEEN the Bridge and the bank of Regulators (some 78xx, 79xx, 317, 319). The Nichicon HE caps reduced the residual AC ripple to approx 1V p-p (with no discernible difference between the 25V and 50V cap). The other caps reduced the residual ripple to 2V p-p. See attached pictures. This is a test which any of you can easily do, any time.

/g/TekScopes/album?id=59343


6. That proved to me that the HE has a significant advantage in reducing AC ripple, over another respected brand-name cap. On the datasheets, all the numbers pretty much matched up, but in the real world of flowing voltage and current, my scope waveform showed a substantially significant advantage to the HE.
7. However, AFTER the regulators, where ripple is negligible, an EB is an excellent choice. The superior capability of the HE regarding ripple damping is of no advantage here.

On this Tek PSU, has anyone actually done any research to specify each cap’s function? From the postings here, I don’t think so. I haven’t. So, unless someone is willing to go and locate each cap on the circuit, and determine whether it is in a low-ripple part of the circuit (where an EB would be acceptable), or it is in a high-ripple part, I think that we need to globally specify HE or PW (functionally equivalent), in order to be on the safe side for ALL applications. That’s what I did, with full confidence that my choice would give me the lowest ACTUAL ripple on all circuits.

If a user installs EB in a high-ripple area BEFORE the regulators, will the machine work? Of course it will.
But will it work as well, if an HE or PW is installed? My test states not.
After all, a SMPS with loads of AC ripple in all parts of the circuit, is NOT like a linear PSU, at all.

It’s the difference in being able to tune a high-performance engine, to get the last ounce of available HP out of it.

The posters who are asking these questions are people who do NOT have any substantial electronics background, theory or practice. I think it is incumbent on us (the techs with long experience) to point them in a direction which will give them an optimal and safe solution, so that they don’t have to tear their hair out, buying parts which don’t fit, or worrying whether what they choose will last or not.

Regarding the Lifetime numbers of the data provided by MachineGuy:

A 5000Hr lifetime is provided for a (boiling) CONSTANT temperature of 105°C. If the caps in my Tek scope are reaching that temperature, then my scope is on the way to the garbage dump, very quickly, and the 5000hr lifetime is functionally irrelevant.

I have measured the temperature of my HE caps in my A2A1/A3 PSU block, and the hottest individual cap temperature which I measured was 38°C. The average temp of the caps was room temperature.
And it IS hot here in Israel – I’m not just talking about the fires from the Gazan terrorists.



“For every 10 degree Centigrade decrease in operating temperature, the capacitor life is extended by a factor of two.”

So, if my HE caps are running at a constant 40°C, then their expected lifetime is 5000 x 2 to the power of 6 (=64, check my math) = 320,000 hrs = more than 36 years; scope on all the time, never being switched off.

Given that the data supplied above stated that cap’s casing would breakdown after about 15 years, then there is no apparent benefit HERE of choosing a 10000 hr cap over a 5000 hr, except for the status.

So, IMO what we should be concerned about, is WHAT does the waveform look like at all the HIGH-RIPPLE positions in this Tek SMPS PSU circuit, and then select the cap which dampens that ripple most effectively. To my experience, the Nichicon HE fits the bill most effectively.

Menahem

Looks like it is very clean, If I still lived in Ft worth I'd run over
and turn it on to check it out. has probes and all.

100MHz Analog Scope ( later 150MHz version I think) plus a built in DMM
More info over on Tekwiki

Godwill in the auction business ..who knew

-DC
manuals@...

On 6/16/2018 11:47 AM, David Berlind wrote:

I'm sure everyone here has seen one of these. But I haven't. Is it some

sort of hack of a digital scope? It looks mint (and cool).

I have no affiliation with the seller.

--
Dave
Manuals@...
www.ArtekManuals.com

Ohio here. Not exactly a stone's throw. If I could get there it would be with my friend the truck driver who goes that way alot, but I either couldn't stay more than a few minutes or need another way home. Driving it is out of the question for me.

Anyway, I AM going to see about the scope testing itself. There is no technical reason it should not work and ground is absolutely not a problem. Now if you needed some differential readings in the vertical, that would be a problem. I'll put up some pictures if I can find batteries for this batteryaholic camera I got. I was going to build a PS for it but I have to get 3 volts at about 7 amps ! Even though it runs off AA cells, they can put out that, and more.

I might do that tonight. Meantime, post yours. I would like to see what those collector (not the test point) waveforms look like at about 26 VDC input. That is about what they would get with 125 VAC at the wall, which is actually the new nominal. Now that I mention it, I am not sure what range mine is set for. If it is set for like 110 volts, changing that might help.

From: Jeff Urban <JURB6006@...>

In hifi audio restoration circles they have a process they call "pinning". This is used on Marantz Dolby decoder boards and other things that were two sided but only had plated through, no rivets, gripplets or anything.

All it is is to identify all the vias and stick a wire through, solder it on both sides and then trim it. It works. It can be tedious though, and they charge $$$ to do it. But their customers are the most picky, persnickety anal customers in the world sometimes. But then they pay, like hundreds for simply speaker wires.

Even though they charge good money for "pinning", it is cheap. All it takes is a bunch of those leftover leads you cut off resistors and whatever after you put them in a board. You DO save those right ? If not, the length needed is so short you can do many connections and only ruin one new resistor.

I don't see a viable (no pun) automatic way of doing it, RE-wave soldering won't work, or the problem would have never happened in the first place.

Seems like the problem isn't as bad now, as if the process got improved or something. I have worked on plenty of two sided boards and really not had a problem with the vias. Maybe they are somehow putting more copper into those holes,. I don't know. but I do know that in the past these things were problematic.

Thing is, on a given board, just how many do you have to do ?

You can still buy the pop rivet nuts, but much more $$ than that.
You said they use an adapter, I have never seen that. Around here you
need to buy a dedicated rivet nut tool for around $100 (which looks
much like a slightly modified $20 pop rivet tool).

I always speculated that they are set just like a pop rivet, but with
a threaded rod instead of the discardable metal shank in a regular
rivet.
My plan was, should I ever need to set a rivet nut, that I would take
a hard screw and put that in the rivet, and pull on the screw from the
outside with a washer and a nut.

Do you have any opinion if that plan might succeed? I have been
curious about it for years.

ST

On Sat, Jun 16, 2018 at 5:40 PM, Michael A. Terrell
<mike.terrell@...> wrote:

They also made the rivnut,which is an internally threaded version of a pop rivet that used an adapter to set with a pop rivet tool. I used them in some projects. I wished that I had boght more of them, surplus. They were 50 cents/100 in USM boxes.


Michael A. Terrell

You know on many internet groups that title results in one of the most long and popular threads ever, right ?

LOL

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of
Jim Strohm
Sent: Wednesday, June 13, 2018 3:16 PM
To: [email protected]
Subject: Re: [TekScopes] NEW to the group

ironcoder@...
<ironcoder@...?subject=Re:%20NEW%20to%20the%20group> said

"Eric, I am not optimistic about our chances of not using nukes again.
There are groups in the world who would not hesitate to use a nuke if
they got their hands on one. I believe the USA would use nukes in
retaliation for an attack on America without really knowing who set
off the nuke that attacked America. Even an angry president could go
ahead and start something like this. Our world without nuclear war is
on a tenuous footing "

Actually, while we'd need a declaration of war by Congress before
launching a retaliatory strike, given that the Gulf of Tonkin
resolution is still in place, President <somebody somebody mumble>
could push the button on a retaliatory strike before the missile
entered US air space -- actually maybe even before the bits and pieces
of that missile landed in the Pacific or Arctic ocean after we
destroyed the missile with our anti-missile defense systems. We DO
have sophisticated enough space-based systems to monitor everybody
capable of using an ICBM against us or an ally, and enough globally
dispersed resources to kill a billion people in five minutes.

And DO NOT doubt the ability of President <somebody somebody mumble>
to sign an executive order providing for an instant-messaging-enabled
emergency meeting of Congress, provide a boilerplate declaration of
war with Speaker Ryan's pre-signed electronic signature on it, and
have a Constitutionally valid declaration of war in place before the
short-range Polaris missiles from the boomer submarines landed. It's
the Soviet "dead hand" machine, except via Facebook.

I hope we don't see anything like this in any of our lifetimes,
because enough nations still have (or recently have developed)
sufficient mutually assured destruction capabilities to slag the
planet. And we remember what happened to the last President who tried
to STOP a nuclear war.

We also remember what happened the last time a President invaded the
wrong country for an act of war committed on American soil.

73
Jim N6OTQ

PS -- Obligatory electronics tech content -- a few years back, I gave
my wife a gag gift to give to her MD boss who'd just installed a new
X-ray machine. It was a cold-war era radiation dosimeter pen, the
kind you looked through and when you couldn't see through it any more,
it meant that you'd been over-exposed to radiation. Freshly removed
from its 50-some year-old lead envelope. She carried it in her purse
for a couple of years, and ... now it's completely black inside. So
either background radiation got it, or else the doc's X-ray machine
got her.