Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Old February 11th 19, 11:50 PM posted to sci.electronics.repair
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Default Who makes RELIABLE modern electrolytic caps?

On Monday, February 11, 2019 at 12:04:17 PM UTC-5, Chuck wrote:
On Mon, 11 Feb 2019 00:32:54 -0600, wrote:

Changing the electrolytic capacitors in vintage tube gear is a must
these days, but no one makes the old style (large size) caps anymore.
I personally do not trust these small modern caps to last very long.
Many computer motherboards have proven how short the life span is on
modern caps, and most of them are low voltage types.

Those old caps have lasted 40, 50 sometimes 60 years. I doubt any modern
caps will last even 10 years. I tend to wonder if that is because of
their small size. Or is it just the construction or materials used?
There are some NOS (new old stock) caps available, but they fail
regardless if they were used or not, since the electrolyte drys out and
moisture may enter them as well.

I dont mind changing caps on vintage gear once, but if I have to change
them every 5 or 10 years, I will not be happy.

But since new caps are no longer made, which are made the same as the
old ones they are replacing, I have little choice but to use these small
modern ones.

That leads to finding brands which are reliable. And I assume price
tells all. Cheap imports are likely the worst, while high priced US made
ones will last longer.

I doubt any modern caps will last even close to the life span of the old
ones, but which brands are the best? (Particularly the ones used for
high voltages in tube gear).

Panasonic and Nichicon.




When I build (or rebuild) something for myself, I always go with Panasonic capacitors.
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Old February 12th 19, 04:26 AM posted to sci.electronics.repair
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Default Who makes RELIABLE modern electrolytic caps?

In article ,
says...

Even the big name companies have problems. I have some test get that I
bought surplus when the cell phones went from the 800 Meg to higher
frequencies. The $ 50,000 piece of gear had capacitors go bad in the
switching supplies. That was made around 1995 so they only lasted about
20 years.

I don't know how long they will last, but I just bought a lot of
capacitors from China off ebay. About a dozen of them are in use in my
equipment and have worked for the last 3 months. They may or may not go
out today. I would not put them in equipment that I was repairing for
anyone for money, but this isfor my hobby work.


I don't think you're understanding why they died.



I think I have a fair understanding of why capacitors die.

The could be made out of crap materials like the ones on the computer
boards.

The switching power supplies really stress capacitors and they need to
have a low ESR.


Heat will be bad for them. Some are rated around 85 and some are rated
over 100 deg C.

The voltage ratings should be in the correct range. If they sit around
a long time some will need to be reformed to meet the voltage
requirement. Some of the capcitors are formed at a higher voltage than
they are rated for to insure that as they age on the shelf they will
still meet the rated specifications when used year or more later.


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Old February 12th 19, 06:03 PM posted to sci.electronics.repair
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Default Who makes RELIABLE modern electrolytic caps?

On Mon, 11 Feb 2019 10:05:09 -0800, wrote:

On Mon, 11 Feb 2019 00:32:54 -0600,
wrote:

Changing the electrolytic capacitors in vintage tube gear is a must
these days, but no one makes the old style (large size) caps anymore.
I personally do not trust these small modern caps to last very long.
Many computer motherboards have proven how short the life span is on
modern caps, and most of them are low voltage types.

Those old caps have lasted 40, 50 sometimes 60 years. I doubt any modern
caps will last even 10 years. I tend to wonder if that is because of
their small size. Or is it just the construction or materials used?
There are some NOS (new old stock) caps available, but they fail
regardless if they were used or not, since the electrolyte drys out and
moisture may enter them as well.

I dont mind changing caps on vintage gear once, but if I have to change
them every 5 or 10 years, I will not be happy.

But since new caps are no longer made, which are made the same as the
old ones they are replacing, I have little choice but to use these small
modern ones.

That leads to finding brands which are reliable. And I assume price
tells all. Cheap imports are likely the worst, while high priced US made
ones will last longer.

I doubt any modern caps will last even close to the life span of the old
ones, but which brands are the best? (Particularly the ones used for
high voltages in tube gear).

Yeah, I totally agree with you. The new smaller modern caps just can't
last. A perfect example. My Pioneer SX-434 is only 46 years old and
the ****ty small caps in it must be getting ready to fail. Even though
I listen to it every day and though there is no degradation in the
tuning or the sound I just know the caps must be getting ready to
fail. They are just so small.
Eric

When you finally have a failure, I would replace all Sanyo brand
capacitors.


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Old February 17th 19, 08:11 AM posted to sci.electronics.repair
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Default Who makes RELIABLE modern electrolytic caps?

On Mon, 11 Feb 2019 13:32:07 -0500, Ralph Mowery
wrote:

In article ,
says...

On 2/11/19 9:43 AM, Ralph Mowery wrote:
Remember the computer boards that had capacitors
on them that only lasted about a year ? A friend and I had to send back
several boards to one of the big computer board and part suppliers , but
that was about 20 yars ago.


That wasn't because of modern capacitors.
That was because the bean counters at Dell went with
cheap counterfeit caps that were ****.




The origional post was about which brands were the best.

That is why I said not all modern capacitors would last. I am sure
there are lots of crap China brands of capacitors. I probably bought
some a few months back, but they go in my hobby electronics.

The boards I sent back were not Dell. They were some boards from a
company that sold computer boards and parts that I put together a
computer. The boards were high rated before the capacitor problem. I
think lots of companies had the cpacitor problem from that particular
capacitor company.

One of the main things is that the switching supplies or high
temperature are the main killers of the capacitors.

Any of the good brand capacitors should last longer than most of us will
be around.


Yes, the original question was which caps are BEST, but much of my
concern is based on the failed motherboards, which only lasted a year or
so.

Knowing the name used on these really bad junk caps would be useful to
know too. I'm pretty fussy when I buy caps and some other components,
but I do sometimes buy "grab bags" (like on Craigslist) if the price is
right, and I know some parts will be usable. But knowing the name used
on those conterfeit caps, or any others known to fail is good to know.
If the caps are known bad, I am not going to use them for anything other
than a breadboard test design, (or not at all).

I'm curious what brand of motherboards were the bad ones too....

It's just good to know things like this. Just like every brand of car
seems to have certain common failure or breakdown problems, and knowing
what to check and watch for, is helpful.


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Old February 17th 19, 11:05 PM posted to sci.electronics.repair
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Default Who makes RELIABLE modern electrolytic caps?

Fox's Mercantile wrote:


wrote:
Yes, the original question was which caps are BEST, but much of my
concern is based on the failed motherboards, which only lasted a year or
so.


Which, as usual, you didn't make at the beginning.

The Failed motherboards were, Dell.
Their "Lets buy cheap ****" almost put them out of business.
And that was almost 20 years ago.


** This old Wiki has the story:

https://en.wikipedia.org/wiki/Capacitor_plague

The brands of capacitor involved were previously unknown and unable to be linked to any of the well known makers.

AFAIK the issue never involved electros that might be used in restoration of vintage tube gear.

"tubeguy" is a ****wit - see " top definition " :

https://www.urbandictionary.com/define.php?term=****wit



..... Phil
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Old February 17th 19, 11:37 PM posted to sci.electronics.repair
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Default Who makes RELIABLE modern electrolytic caps?

On Sun, 17 Feb 2019, Phil Allison wrote:

Fox's Mercantile wrote:


wrote:
Yes, the original question was which caps are BEST, but much of my
concern is based on the failed motherboards, which only lasted a year or
so.


Which, as usual, you didn't make at the beginning.

The Failed motherboards were, Dell.
Their "Lets buy cheap ****" almost put them out of business.
And that was almost 20 years ago.


** This old Wiki has the story:

https://en.wikipedia.org/wiki/Capacitor_plague

The brands of capacitor involved were previously unknown and unable to be linked to any of the well known makers.

AFAIK the issue never involved electros that might be used in restoration of vintage tube gear.

"tubeguy" is a ****wit - see " top definition " :

A little knowledge can be a dangerous thing.

People hear the stories, but don't grasp the details. Modern use of
electrolytics is different from the tube days. Not only have values gone
up as size got smaller, but they are often expected to handle much higher
frequencies than 60 or 120Hz in the days of tubes. Electrolytics are also
a lot more common in the days of solid state. In tube days, a bad one
would mean low voltage, or hum, or low audio gain, but there were a
handful of electrolytics. Now they are everywhere, a shift to low
impedance so larger values needed, and that means electrolytics. The
circuitry is now more complicated and a bad capacitor may not be so
obvious as in the old days.

Michael


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