Longevity of electrolytics

[David Nebenzahl]

There's a lot of discussion here about the quality and longevity of
electrolytic capacitors, and to read much of it, one would think that
these are the most failure-prone of all electronic components, and that
any piece of equipment you may have around the house (or lab) that uses
them is likely to fail any day now.

I can't really dispute any of this, except to say that this is not my
experience at all.

Three pieces of electronic equipment I use every day: my computer
(motherboard is about 10 years old), my "good" audio equipment (Technics
amplifier, Vector Research tuner, both somewhere between 15-20 years
old), and the receiver I use for sound on my computer (an Allied that I
bought *used* in 1975).

I have other old elecronic stuff that also works fine.

None of these have had any electrolytics fail, so far as I know. So what
gives? Am I just lucky? Did the manufacturers use higher-quality caps
than what's commonly used today? (The motherboard ain't anything
special--it's an Asus, I think, but I do have extra fans in the enclosure.)

 

[William Sommerwerck]

I don't think you're lucky. I've almost-50-year-old tube equipment with the
original electrolytics that worked just fine.

On the other hand, I have two JVC hall synthesizers, both of whose
power-supply electrolytics have leaked, one to the point where they had to
be replaced. JVC was aware of this; the caps were apparently from a bad
batch of around 30 years ago.

You'd think electrolytics would be highly unreliable, but they generally
aren't.

 

[Geoffrey S. Mendelson]

There's a lot of discussion here about the quality and longevity of
electrolytic capacitors, and to read much of it, one would think that
these are the most failure-prone of all electronic components, and that
any piece of equipment you may have around the house (or lab) that uses
them is likely to fail any day now.

I can't really dispute any of this, except to say that this is not my
experience at all.

Around 2002 there was a big scandal about it. A Tiwanese company hired an
engineer to work for a Japanese company that made electrolyte (the stuff
inside the capacitor) with the intention of them bringing their trade
secrets back to Tiawan for the new factory the company was opening.

The Japanese were on to the scam, and allowed the engineer to learn everything
they needed EXCEPT a preservative for the electrolyte. It was pretty sneaky
because the capacitors produced passed every test, but would start to pop open
after about 6 months of use.

Almost every company on the island bought from them because their price was
around half of the Japanese company. Within a year, everything that contained
their capacitors failed.

In the end, besides millions of items being replaced, it taught everyone
in the business exactly how long something had to last before people
stopped complaining when it failed and just replaced it.

Geoff.

 

[Charles]

Electrolytics are generally more prone to failures than other types of
capacitors. Not to say that one has to be paranoid about them!

They:
1/ can develop high series resistance as they dry out
2/ can exhibit more leakage over time (both electrical and physical)
3/ can lose their effectiveness over time (mostly as they dry out)
4/ can explode due to internal gassing
5/ can damage circuit boards when they physically leak their electrolytes
6/ are mostly intolerant of reverse polarity
7/ are absolutely the best choice in many designs

 

[spamme0]

It's not a case of being lucky, for the most part. It's more a case of the
equipment that you're talking about, being old. Electrolytics which fail in
modern equipment, are almost always in switch mode power supplies, or are
post-psu decouplers. The ones that are actually employed in the psu itself,
are under enormous stresses from the high frequencies that they have to deal
with, and it is essential that in order to minimise failure through self
heating, only top quality low ESR high temperature types are used.
Unfortunately, such caps impose an increased financial burden on the design,
so even if the designer had good intentions when he specced them, the bean
counters are likely to demand a cheaper lower specced type is used in the
production version.

Add to this that much equipment now is very small, and the caps in question
will be further stressed by being specced for the smallest physical size
that will do the job, and that often means that the voltage rating will be
only a couple of volts above the actual voltage that they have to work at.
Now I know that there have been those on here in the past, who have got
really worked up about this, saying that if a cap is rated at 10v, then it
should work at 10v applied, for ever, without complaint. Maybe. On paper.
But any of us who are in the repair business, will tell you that in real
life, it just ain't so ...

The old equipment which you have, and which you and others in the thread say
has never suffered any electrolytic problems, is not exhibiting anything
special. 20 years ago, electrolytics were physically bigger for any given
value / voltage rating, so had a bigger surface area to dissipate any heat
from. As the equipment was larger in the first place, there was no
requirement to compromise on voltage rating to get a cap that would fit in
there. The larger internal size also allowed for better air circulation, and
a lower overall internal working temperature. Switch mode power supplies
were a dim idea for the future, so the caps did not suffer high frequency
stress, either.

All of that said, Panasonic / Technics gear suffered for many years with the
little purple 10uF decouplers going short circuit, and you would be
surprised how many cathode bypass electrolytics in valve (tube) amps, are
virtually open circuit, if you take the trouble to check them, and how much
it improves the performance, when they are replaced ...

So, in conclusion, I would definitely say that in my daily repair
experience, electrolytics are now by far and away, the commonest component
to fail, and this, IMHO, is for all of the reasons that I have stated.

Arfa

agree, but it may be worse than just replacing the caps.
Most switchers start with a higher voltage.
As the capacitance reduces and the series resistance increases,
the regulator maintains an average output voltage somewhere near
the spec. Problem is that the load electronics cares about the peak
voltage too. High voltage spikes can take
out all the downstream electronics.

Maybe it doesn't matter when labor costs exceed the cost of a new device,
but I think the fun times are coming to an end for those of us who
like to buy cheap busted stuff and fix it.

Anybody want to buy a monitor with a logic board killed by 20V overvoltage
spikes?

 

[David Nebenzahl]

Most of these are likely lacking the part which taxes caps - an SMPS.

Well, if you re-read what I wrote, real carefully this time, you'll find
that there's at least one thing that most definitely *does* have a SMPS,
which hasn't failed yet.

And I have other stuff with SMPSs that haven't failed yet either.

 

[Geoffrey S. Mendelson]

Well, if you re-read what I wrote, real carefully this time, you'll find
that there's at least one thing that most definitely *does* have a SMPS,
which hasn't failed yet.

And I have other stuff with SMPSs that haven't failed yet either.

It's not that the one unit has an SMPs and another does not. It's that the
SMPs in question are designed, like the rest of the unit, to last longer
than the warranty, but not much more.

Since most consumers choose soley on price the only concern of everyone is that
the units last at least a day longer than the warranty. There is no need for
anything else because if it fails, they are not going to buy a different brand
or go to a different store because they "felt cheated", they are just going
to look for a replacement at the lowest possible price.

Very likey if it is an item which can be shipped, it will be bought from
an internet retailer. Being interested in photography, I'm sure you remember
all of those mail order scam dealers some of whom are still around, even after
ripping off customers for since the 1960's.

Like many of those camera dealers, internet retailers are often the same
company using different names.

Geoff.

 

[Mark Zacharias]

There's a lot of discussion here about the quality and longevity of
electrolytic capacitors, and to read much of it, one would think that
these are the most failure-prone of all electronic components, and that
any piece of equipment you may have around the house (or lab) that uses
them is likely to fail any day now.

I can't really dispute any of this, except to say that this is not my
experience at all.

Three pieces of electronic equipment I use every day: my computer
(motherboard is about 10 years old), my "good" audio equipment (Technics
amplifier, Vector Research tuner, both somewhere between 15-20 years old),
and the receiver I use for sound on my computer (an Allied that I bought
*used* in 1975).

I have other old elecronic stuff that also works fine.

None of these have had any electrolytics fail, so far as I know. So what
gives? Am I just lucky? Did the manufacturers use higher-quality caps than
what's commonly used today? (The motherboard ain't anything special--it's
an Asus, I think, but I do have extra fans in the enclosure.)

Replaced 2 shorted 2200uf / 16v axial caps in a McIntosh 2205 just
yesterday. They were Euro crap - Rodersteins or some such.

To me it just seems that quality rules but is not always predictable. No
doubt McIntosh thought these caps were just fine. 30 years later, the caps
fail - I suspect due to the oxidation / tarnish we often see on Euro metals.

I once worked on a Honeywell (Philips-built) defibrillator on which the fuse
holders were so crusty and blackened with tarnish they wouldn't even conduct
electricity to the fuses they were holding!

I wouldn't want my life depending on that one...

Mark Z.

 

[Geoffrey S. Mendelson]

Chuckle 2.0. Statistics time. Let's pretend that a large quantity of
old electrolytic capacitors were defective. In that case, they would
have died long ago, been recycled, leaving only the good electrolytic
capacitors. 30 years later, all you see are good working ancient
equipment. Not having seen the older blown caps, you might presume
that all ancient electrolytics are reliable over a long term.

Go over to any of the newsgroups, mailing lists or websites dedicated to
using tube, as in when they were popular, not modern stuff because "it sounds
good" radios.

The first thing anyone will tell you is check the tubes, the second is replace
ALL of the capacitors starting with the electrolytics. Electrolytics dry out
from lack of use, and there are ways of getting them working again without
destroying them, but it is not always successful.

.....

Incidentally, I have a 486DX2/66 and Conner 1Gbyte SCSI HD in my
palatial office, running SCO Open Desktop 3.2v4.2 since about 1990.
The PS blew up at one point and I've blown 2 CPU fans, but otherwise,
it's much the same today as it was 19 years ago. From this evidence,
do I deduce that the older motherboards, hard disks, and operating
systems are more reliable than today's equivalents?

So David and Jeff, the chance of the devices you mention that are in
continous usage still working tomorrow morning is pretty good.

The chances of the identical device having sat for almost 20 years in a closet
without being touched is almost nill.

As for Jeff's conclusion, I would say the evidence supports it, which is not
proof. On the other hand since the great capacitor disaster of 2002, I would
say yes, the modern equipment is not designed with long term longevity in
mind.

Geoff.

 

[David Nebenzahl]

It's not that the one unit has an SMPs and another does not. It's that the
SMPs in question are designed, like the rest of the unit, to last longer
than the warranty, but not much more.

I'm not so sure about that. In this case, the warranty has long been
expired, yet the power supply merrily chugs along. (I bought it in
1999.) So how long do you consider to be "not much more" than after the
warranty expires?

Let's get a little more specific here, pleeze.

 

[Geoffrey S. Mendelson]

I'm not so sure about that. In this case, the warranty has long been
expired, yet the power supply merrily chugs along. (I bought it in
1999.) So how long do you consider to be "not much more" than after the
warranty expires?

David, I was referring to devices built after the massive capacitor failure
in late 2002. After that people no longer expected indefinite life out of
consumer electronics.

That's why there are many Pentuim III and equivalent computers still in use
and almost no Pentium IV slightly newer ones.

Geoff.

 

[JB]

There's a lot of discussion here about the quality and longevity of
electrolytic capacitors, and to read much of it, one would think that
these are the most failure-prone of all electronic components, and that
any piece of equipment you may have around the house (or lab) that uses
them is likely to fail any day now.

I can't really dispute any of this, except to say that this is not my
experience at all.

Three pieces of electronic equipment I use every day: my computer
(motherboard is about 10 years old), my "good" audio equipment (Technics
amplifier, Vector Research tuner, both somewhere between 15-20 years
old), and the receiver I use for sound on my computer (an Allied that I
bought *used* in 1975).

I have other old elecronic stuff that also works fine.

None of these have had any electrolytics fail, so far as I know. So what
gives? Am I just lucky? Did the manufacturers use higher-quality caps
than what's commonly used today? (The motherboard ain't anything
special--it's an Asus, I think, but I do have extra fans in the enclosure.)

This is funny!

Anyone who has had thousands of various pieces of equipment across the bench
knows about this, but how do you make sense to people who had "Three pieces"
that work?

I don't agree that all caps should all be automatically replaced. There are
a great many reasons they fail. Any manufacturer has certainly had failures
in the production run of some model that either had supplier problems, or a
latent quality issue of a specific run of a part that only showed up in a
specific circuit or application. In the past, serious manufacturers had a
factory authorized service network in order to get specific feedback.
Lessons that were learned now allow untouchable offshore facilities to
shovel cheap products. Quality control is a major job involving tracking of
every part shipment and production change. Aside from that, it is obvious
that capacitors have been a long time problem in trying to get costs and
size down, make them survive, and design around them. Not all Caps are the
same and not all are created equally and some see a harder life than the
rest of their kind.

 

[Adrian Tuddenham]

Chuckle 2.0. Statistics time. Let's pretend that a large quantity of
old electrolytic capacitors were defective. In that case, they would
have died long ago, been recycled, leaving only the good electrolytic
capacitors. 30 years later, all you see are good working ancient
equipment. Not having seen the older blown caps, you might presume
that all ancient electrolytics are reliable over a long term.

I've just had to change a 16uf 450v electrolytic in my Solartron CO 546
signal generator. It's the first one to dry out since the generator was
made in the 1950s but I'm not drawing any statistical conclusions from
that.

 

[GregS]

David, I was referring to devices built after the massive capacitor failure
in late 2002. After that people no longer expected indefinite life out of
consumer electronics.

I got that feeling well before 2002.

greg

 

[Geoffrey S. Mendelson]

I got that feeling well before 2002.

At one time Japanese cameras came with a little sticker, "JCII Passed",
from the Japan Camera Inspection Institute. Sometime in the 1980's they
started to show up with stickers that said "Passed" or "QC Passed",
which meant nothing.

Pretty soon it spread to all sorts of consumer items, including electronics.

That's when I got the feeling that quality control had been forgoten about.
What really clinched it for me was when I saw for the first time a Tiawanese
knock-off of a Japanese knock-off of US product.

Now you can get PRC made knock-offs of Korean knock-offs of Tiwanese
knock-offs of Japanese knock-offs of US products legally sold under the
original brand name. :-(

Geoff.

 

[Slang]

....................... From this evidence,

do I deduce that the older motherboards, hard disks, and operating
systems are more reliable than today's equivalents?

Sure!!!!
30 years ago, market was growing all over the world.
Now things are different: in our countries (1st world...) people MOSTLY
CHANGE their apparatus when them are broken.
So.....
Slang