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It not just that... go search for "tin whiskers". We have nothing toI also suspect that the eco-fanaticism that has given us lead-free
solder doesn't help either, as the elevated process temperatures
required to get this hateful stuff to stick to anything other than
itself, is known to not do some components a lot of good, and I'm sure
that, no matter how comparitively brief these additional early-life
heat stresses on the electros are, they have to be at least another
potentially destructive factor to consider in terms of long life and
reliability ...
I wonder what's going to happen when these lead-free joints start
failing en masse... I can just see a class-action suit against the
European Economic Community.
You cannot get large capacitance values in a small package size with aWilliam Sommerwerck wrote:
If I interpret your question correctly, it's meaningless.
Polymer capacitors (ie, plastic-dielectric caps, such as polystryrene,
Mylar, and Teflon) simply cannot produce the huge capacitances in small
spaces that electrolytics can. They cannot easily replace
electrolytics.
How about ceramic caps?
So why do the good brands tolerate those conditions so well while theTo some extent, I don't think it is all the capacitors' fault, to be honest.
The places that electrolytics are found in today's equipments, tend to be
very stressful to them, when you couple in other factors such as the
international law on pain of death that requires designers to place electros
as close as is physically possible to anything that runs hot, and then to
mount the power supply or whatever board they're on, upside down in the
corner of the equipment with the least airflow, it's actually not that
surprising that these devices exhibit such *apparent* unreliability.
But the problems with junk capacitors showed up way before the switchI also suspect that the eco-fanaticism that has given us lead-free solder doesn't
help either, as the elevated process temperatures required to get this
hateful stuff to stick to anything other than itself, is known to not do some
components a lot of good,
Ok, I stand corrected.Jeff Liebermann wrote:
The caps in the photo really are solid polymer caps:
http://www.dslreports.com/forum/r19863881-Solid-Polymer-Capacitor-Failure
The caps in the photo really are NOT solid polymer caps.
Groan. So much for my method of using the case style to recognize theThey're regular Sacon brand conventional wet electrolytics, only
housed in the same kind of packaging normally used for polymer caps.
So that's the trick to recognizing the difference. Thanks.Even some of the replies in the message thread where that photo is
from mention this. Real polymer caps, except Fujitsu hybrids, don't
have explosion rupture cutouts, unlike the caps in the photo -- notice
the "K" rupture cutout on top of each cap.
Arfa Daily wrote:
To some extent, I don't think it is all the capacitors' fault, to be
honest.
The places that electrolytics are found in today's equipments, tend to be
very stressful to them, when you couple in other factors such as the
international law on pain of death that requires designers to place
electros
as close as is physically possible to anything that runs hot, and then
to
mount the power supply or whatever board they're on, upside down in the
corner of the equipment with the least airflow, it's actually not that
surprising that these devices exhibit such *apparent* unreliability.
So why do the good brands tolerate those conditions so well while the
same old junk brands don't? And contrary to what you say, most of the
caps aren't in hot spots but are running at under 60 Celcius
I don't dispute that junk capacitors have been failing for a long time, butI also suspect that the eco-fanaticism that has given us lead-free solder
doesn't
help either, as the elevated process temperatures required to get this
hateful stuff to stick to anything other than itself, is known to not do
some
components a lot of good,
But the problems with junk capacitors showed up way before the switch
to lead-free solder, and only one of my RoHS mobos has so far popped a
cap, probably more because it's newer (late 2007), not because it's
better, but it has the same OST brand junk caps.
Some of the fault lies with the makers of junk, agreed. But not all, by anyThe real fault lies with the makers of junk, period.
I'm in complete agreement with Arfa. Internal heating caused by theAs far as your contention that most of the caps that fail are running
at under 60 deg and are not in hotspots, that may be true if you are
talking just mobos, which are a bit of a special case in that apart
from all the problems that have been caused in the past with boards
built using caps with fake electrolyte, the caps that fail are all
decouplers on constant DC rails, and are rated voltage wise pretty
close to the continuous voltages that are applied to them. Even
accepting that, many of the decoupling caps that do fail on mobos, are
sited very close (by nature of the job that they have to do) to LSIs
which *do* run very hot.
The caps that I am talking more about in general, are on switch mode
power supplies, where they are subjected to huge stresses from the
high frequency pulse currents that they have to endure, and the self
heating caused by this in all but the most expensive types, very
specifically specced for use in these positions. Further, the ones
that fail most regularly are, without doubt, the ones positioned close
to heatsinks. I replace hundreds every year in the course of my daily
work. Although the caps positioned on switchers are by far the most
common ones to fail, they are by no means the only ones. I also
replace many in other circuits, for instance audio output stages,
where failed ones are almost invariably close to heatsinks.
Arfa
Generally true. This is old (2005) but the best I could find:As far as your contention that most of the caps that fail are running at
under 60 deg and are not in hotspots, that may be true if you are talking
just mobos,
Worse. The caps are not on constant DC. There are huge ripplefake electrolyte, the caps that fail are all decouplers on constant DC
rails, and are rated voltage wise pretty close to the continuous voltages
that are applied to them.
Yeah, but along with the general decrease in quality, there has beenHowever, if we take junk out of the equation, anyone
directly involved at the sharp end of electronic service will tell you, as I
do now, that over the last five years or so, the incidence of electrolytic
failure has increased a lot with the increased use of switchmode power
supplies in all sorts of consumer equipment, and the unstoppable rise of
Chinese designed and manufactured equipment, where many good design
practices, such as ensuring adequate ventilation, are not observed on cost
grounds.
Good point. I have no idea if there is a correlation but it seemsAs to whether the increased process temperatures of lead free
soldering has had any effect on long term reliability of electros, I really
don't know for sure. I could be wrong, but it seems to me that over the last
couple of years, the incidence of electrolytic failure has increased even
more than the trend of the last 5 or 7 years, so it was just a thought in
that this was something else that had changed in that timeframe, and may
have been a contributory factor
They wouldn't make junk if consumers didn't demand low prices. ThereThe real fault lies with the makers of junk, period.
Some of the fault lies with the makers of junk, agreed. But not all, by any
means.
That better quality components tolerate abuse more readily than cheapo"larry moe 'n curly" <larrymoencurly@my-deja.com> wrote in message
news:a4e6ca4a-6925-4866-8cd6-9c2ccb8e3964@a10g2000pre.googlegroups.com...
To some extent, I don't think it is all the capacitors' fault, to be honest.
The places that electrolytics are found in today's equipments, tend to be
very stressful to them, when you couple in other factors such as the
international law on pain of death that requires designers to place
electros as close as is physically possible to anything that runs hot,
and then to mount the power supply or whatever board they're on,
upside down in the corner of the equipment with the least airflow,
it's actually not that surprising that these devices exhibit such
*apparent* unreliability.
So why do the good brands tolerate those conditions so well while the
same old junk brands don't? And contrary to what you say, most of the
caps aren't in hot spots but are running at under 60 Celcius
So, what exactly are you saying ... ? That better quality components
tolerate abuse more readily than cheapo crap ones ? Very profound ... I
don't think that is actually at odds with anything I said, is it ?
I seem to recall in my original reply to William that part of the reason that he may
have had good luck in regard to electrolytic failure, is the fact that he
has tended in the past to buy better quality equipment where the
manufacturers have been prepared to "design to a better spec with a few
cents more spent on components ..."
electrolytics for the same value?If I interpret your question correctly, it's meaningless.
Polymer capacitors (ie, plastic-dielectric caps, such as polystryrene,
Mylar, and Teflon) simply cannot produce the huge capacitances in small
spaces that electrolytics can. They cannot easily replace electrolytics.
How much bigger (in volume) are polymer capacitors than
Both Asus and Gigabyte make motherboards that they claim use allOn Thu, 19 Nov 2009 21:44:36 -0800, Daniel Prince
neutrino1@ca.rr.com> wrote:
I have also read that there are
motherboards with solid polymer capacitors.
Sure. However, they're very difficult to identify without back
tracking the part number or chopping one in half and looking for the
black goo inside. The clue is that they tend to be short and not very
tall, while conventional electrolytics are much taller:
How much would the retail cost of a computer power supply orYeah, but along with the general decrease in quality, there has been
proportional decrease in price. It's price that driving the decline
in quality. Running the operating temperature and voltages near the
point of failure is one way to save on costs.
They wouldn't make junk if consumers didn't demand low prices. There
are usually "premium" versions of almost any consumer product, but few
can afford the price. (If you want quality, be prepared to pay for
it).
The usual markup from cost to sales to retail prices is about 4.5Jeff Liebermann <jeffl@cruzio.com> wrote:
Yeah, but along with the general decrease in quality, there has been
proportional decrease in price. It's price that driving the decline
in quality. Running the operating temperature and voltages near the
point of failure is one way to save on costs.
They wouldn't make junk if consumers didn't demand low prices. There
are usually "premium" versions of almost any consumer product, but few
can afford the price. (If you want quality, be prepared to pay for
it).
How much would the retail cost of a computer power supply or
motherboard etc. increase if they were made to last twice as long?
Five times as long? Ten times as long?
I don't know the specific numbers for those multipliers.How much would the retail cost of a computer power supply or
motherboard etc. increase if they were made to last twice as long?
Five times as long? Ten times as long?
It seems to me that there is a good opportunity here for otherThe problems start when there are competing products. I call it the
Walmart effect. Walmart, Kmart, and many online vendors specialize in
selling solely on the basis of price. If there are two competing
products, differing only a few pennies in selling price, *ALL* their
orders will go to the lower priced product, with nothing to the higher
priced equivalent. Walmart aggravates the effect by setting the price
at some artificial low level, and challenging their vendors to meet
their price goal.
There are such businesses. However, they are small and the number isJeff Liebermann <jeffl@cruzio.com> wrote:
The problems start when there are competing products. I call it the
Walmart effect. Walmart, Kmart, and many online vendors specialize in
selling solely on the basis of price. If there are two competing
products, differing only a few pennies in selling price, *ALL* their
orders will go to the lower priced product, with nothing to the higher
priced equivalent. Walmart aggravates the effect by setting the price
at some artificial low level, and challenging their vendors to meet
their price goal.
It seems to me that there is a good opportunity here for other
retailers. If a retailer sold only electronic goods that were well
made and well designed, they could sell them for ten to thirty
percent more than the junk sold at Walmart and Kmart.
I'm sure there are those out there. Whether they can support a retailI think many consumers would be willing to pay a little extra for
devices that would probably last four to ten times as long. This
would be especially true if they had two (or more) cheap-junk brand
devices fail.
Welcome to Realityland. A former ladyfriend was a buyer for a largeThe retailer could require vendors to only use non-junk capacitors
with voltage ratings at least three times the voltage the capacitors
would be exposed to. They could also require that no part of the
device ever get more than 30 degrees warmer than the temperature of
the room it is used in.
More reality. The name of the game in big retail is turnover. MyThe devices could have much longer warranties and the store could
advertise itself as "The quality store". I do not think this would
require excessive advertising, especially after the first few years.
Jeff Liebermann <jeffl@cruzio.com> wrote:
The problems start when there are competing products. I call it the
Walmart effect. Walmart, Kmart, and many online vendors specialize in
selling solely on the basis of price. If there are two competing
products, differing only a few pennies in selling price, *ALL* their
orders will go to the lower priced product, with nothing to the higher
priced equivalent. Walmart aggravates the effect by setting the price
at some artificial low level, and challenging their vendors to meet
their price goal.
It seems to me that there is a good opportunity here for other
retailers. If a retailer sold only electronic goods that were well
made and well designed, they could sell them for ten to thirty
percent more than the junk sold at Walmart and Kmart.
I think many consumers would be willing to pay a little extra for
devices that would probably last four to ten times as long. This
would be especially true if they had two (or more) cheap-junk brand
devices fail.
The retailer could require vendors to only use non-junk capacitors
with voltage ratings at least three times the voltage the capacitors
would be exposed to.
They could also require that no part of the device ever get more
than 30 degrees warmer than the temperature of the room it is
used in.
The devices could have much longer warranties and the store could
advertise itself as "The quality store". I do not think this would
require excessive advertising, especially after the first few years.
... and are cursed with brand new problems.-snip-
The good part about all this is that problem products just don't last
very long. Soon after the problems are found, the replacements appear
in the stores. The replacements have all the latest features, use all
the latest designs, and follow all the latest fashion trends.
I do service work for several retailers of 'quality' consumer electronics,Jeff Liebermann <jeffl@cruzio.com> wrote:
The problems start when there are competing products. I call it the
Walmart effect. Walmart, Kmart, and many online vendors specialize in
selling solely on the basis of price. If there are two competing
products, differing only a few pennies in selling price, *ALL* their
orders will go to the lower priced product, with nothing to the higher
priced equivalent. Walmart aggravates the effect by setting the price
at some artificial low level, and challenging their vendors to meet
their price goal.
It seems to me that there is a good opportunity here for other
retailers. If a retailer sold only electronic goods that were well
made and well designed, they could sell them for ten to thirty
percent more than the junk sold at Walmart and Kmart.
I think many consumers would be willing to pay a little extra for
devices that would probably last four to ten times as long. This
would be especially true if they had two (or more) cheap-junk brand
devices fail.
The retailer could require vendors to only use non-junk capacitors
with voltage ratings at least three times the voltage the capacitors
would be exposed to. They could also require that no part of the
device ever get more than 30 degrees warmer than the temperature of
the room it is used in.
The devices could have much longer warranties and the store could
advertise itself as "The quality store". I do not think this would
require excessive advertising, especially after the first few years.
--
I don't understand why they make gourmet cat foods. I have
known many cats in my life and none of them were gourmets.
They were all gourmands!
If you find yourself cursed, hire an exorcist.On Mon, 30 Nov 2009 12:09:10 -0800, Jeff Liebermann wrote:
-snip-
The good part about all this is that problem products just don't last
very long. Soon after the problems are found, the replacements appear
in the stores. The replacements have all the latest features, use all
the latest designs, and follow all the latest fashion trends.
... and are cursed with brand new problems.