Today I ordered electrolytic caps. It was frustrating. I had planned to get
the best low-ESR replacements for all the caps in some switching power
supplies. I discovered how limited any one manufacturer's low-ESR catalog is.
Many of what I needed (none of which seem to me to be esoteric values) were
not available. A couple of times I had to leave a particular manufacturer's
catalog altogether to find a value.

Which brings me to my question. I was trying to get all Panasonic FM-series
(hi-temp, low-ESR) caps. I've heard good things about Panasonic's caps, but
being forced to another brand I has no idea of comparable quality. (This, at
Digi-Key and Mouser.)

Also, How important is the type of electrolyte? I've read that low-ESR caps
are frequently made with water-based electrolyte whereas non-water-based
formulae cannot give low ESR value.

The qualities of caps (ie, hi-ripple, hi-temp, low-ESR, etc.) are frequently
discussed on electronics forum, but I haven't seen the different
manufacturers compared.

How do the quality of caps compare by

Nichicon
Panasonic
Vishay / Sprague
Mallory
Rubycon
United Chemi-Con
Cornell Dublier
Xicon

Feel free to add to the list, praise, trash, and/or list in order of your
preference. Extra credit for essays on why you like / hate / prefer a brand
or series of caps.

Thanks,
--
DaveC

This is an invalid return address
Please reply in the news group

DaveC wrote:

Today I ordered electrolytic caps. It was frustrating. I had planned to get
the best low-ESR replacements for all the caps in some switching power
supplies. I discovered how limited any one manufacturer's low-ESR catalog is.
Many of what I needed (none of which seem to me to be esoteric values) were
not available. A couple of times I had to leave a particular manufacturer's
catalog altogether to find a value.

Which brings me to my question. I was trying to get all Panasonic FM-series
(hi-temp, low-ESR) caps. I've heard good things about Panasonic's caps, but
being forced to another brand I has no idea of comparable quality. (This, at
Digi-Key and Mouser.)

Also, How important is the type of electrolyte? I've read that low-ESR caps
are frequently made with water-based electrolyte whereas non-water-based
formulae cannot give low ESR value.

The qualities of caps (ie, hi-ripple, hi-temp, low-ESR, etc.) are frequently
discussed on electronics forum, but I haven't seen the different
manufacturers compared.

How do the quality of caps compare by

Nichicon
Panasonic
Vishay / Sprague
Mallory
Rubycon
United Chemi-Con
Cornell Dublier
Xicon

Feel free to add to the list, praise, trash, and/or list in order of your
preference. Extra credit for essays on why you like / hate / prefer a brand
or series of caps.

Toss a coin ?

I'd tend to trust Panasonic btw. They tend to have good specs but even they have
various options. When purchasing for a new project, they are my first choice for
prototyping. At the economy level I'd go for Samwha ( had excellent results ).

Graham

On May 7, 9:53*am, DaveC wrote:
Today I ordered electrolytic caps. It was frustrating. I had planned to get
the best low-ESR replacements for all the caps in some switching power
supplies. I discovered how limited any one manufacturer's low-ESR catalog is.
Many of what I needed (none of which seem to me to be esoteric values) were
not available. A couple of times I had to leave a particular manufacturer's
catalog altogether to find a value.

"low ESR" is not good enough for a purchasing spec. By the standards
of just a few decades ago, all of today's electrolytics are low ESR.
But whether anything meets your requirement is driven by the
requirement, not bullet points in the capacitor maker's glossies.

It's easy to find electrolytics of same voltage and capacitance which
have ESR specs different by a factor of 10 or more. It shouldn't be
too surprising that package and size have a lot to do with ESR. If
your requirements are not met by any commercially available
capacitors, you might think about making your design more
realistic :-).

Digikey etc. let you sort by ESR.

It is also possible to choose capacitors which are too low in ESR and
lead to instability with low-dropout regulators or other circuits.

Tim.

Eeyore wrote in
:

I'd tend to trust Panasonic btw.

Me too. I used them to replace the low ESR caps on an ITX mainboard that runs
in fairly hot and enclosed conditions. The board failed previously because
caps with dodgy electrolyte were used, it leaked, dried, causing poor power
conditioning and early video failure. The problem has not reappeared with the
Panasonic FM electrolytics I used.

Panasonic and Nichicon make about 20 different grades and "types" of
electrolytics. Does one just look for high operating temp and low ESR, or
are there other factors (or combinations thereof) to consider?

On Thu, 7 May 2009 09:42:16 -0700 (PDT), Tim Shoppa
wrote:

On May 7, 9:53*am, DaveC wrote:
Today I ordered electrolytic caps. It was frustrating. I had planned to get
the best low-ESR replacements for all the caps in some switching power
supplies. I discovered how limited any one manufacturer's low-ESR catalog is.
Many of what I needed (none of which seem to me to be esoteric values) were
not available. A couple of times I had to leave a particular manufacturer's
catalog altogether to find a value.

"low ESR" is not good enough for a purchasing spec. By the standards
of just a few decades ago, all of today's electrolytics are low ESR.
But whether anything meets your requirement is driven by the
requirement, not bullet points in the capacitor maker's glossies.

It's easy to find electrolytics of same voltage and capacitance which
have ESR specs different by a factor of 10 or more. It shouldn't be
too surprising that package and size have a lot to do with ESR. If
your requirements are not met by any commercially available
capacitors, you might think about making your design more
realistic :-).

Digikey etc. let you sort by ESR.

It is also possible to choose capacitors which are too low in ESR and
lead to instability with low-dropout regulators or other circuits.

Tim.

And a lot of, maybe most, switchers are stabilized by the filter cap
esr.

John

Tim Shoppa wrote:

Digikey etc. let you sort by ESR.

Manufacturer's data sheets are more comprehensive. And don't forget ripple current.

Graham

William Sommerwerck wrote:

Panasonic and Nichicon make about 20 different grades and "types" of
electrolytics. Does one just look for high operating temp and low ESR, or
are there other factors (or combinations thereof) to consider?

If you get their full catalogues, there should be a selection table.

Graham

In article .net,
DaveC wrote:

Today I ordered electrolytic caps. It was frustrating. I had planned to get
the best low-ESR replacements for all the caps in some switching power
supplies. I discovered how limited any one manufacturer's low-ESR catalog is.
Many of what I needed (none of which seem to me to be esoteric values) were
not available. A couple of times I had to leave a particular manufacturer's
catalog altogether to find a value.

How critically are you trying to match the values?

Please remember that 'lytics are manufactured and sold with a rather
wide tolerance range. For example, the Panasonic FM and FC series
have a +/- 20% tolerance specification, and the nominal values they
list (in the Digi-Key catalog at least) are around 20-30% apart... so
there's some amount of overlap between the values you'd expect to get.

Older caps were often sold with -20% +80% tolerance, which meant that
you could end up getting quite a lot more capacitance than you had
"paid for".

In most cases, these days, I'd just look at the space I have available
to fit the cap, and then pick the "equal or next largest capacitance,
equal or higher working voltage" to what the BOM calls for. Unless
there was a particular need for a specific value (e.g. for timing
purpose) I wouldn't sweat about things like "the BOM calls for a 220
uF, and all they have in that size is a 330 uF."

And, if there were timing issues involved, I don't think I'd be using
a 'lytic at all in that application!

Which brings me to my question. I was trying to get all Panasonic FM-series
(hi-temp, low-ESR) caps. I've heard good things about Panasonic's caps, but
being forced to another brand I has no idea of comparable quality. (This, at
Digi-Key and Mouser.)

I've heard good things about Nichicon, and have used them in some
repair/retrofit projects. Don't have anywhere near enough information
about long-term performance to be of help with your question, though.

Also, How important is the type of electrolyte? I've read that low-ESR caps
are frequently made with water-based electrolyte whereas non-water-based
formulae cannot give low ESR value.

For what it's worth, I've seen several of the PC-motherboard
manufacturers touting their use of solid-electrolyte capacitors for
the CPU VRM... and this is a high-current, high-ripple, low-ESR-
is-very-important application. One manufacturer was citing a "50,000
hour" lifetime figure on the motherboard carton (although I think this
assumes very good cooling of the board).

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On Thu, 7 May 2009 10:34:08 -0700, "William Sommerwerck"
wrote:

Panasonic and Nichicon make about 20 different grades and "types" of
electrolytics. Does one just look for high operating temp and low ESR, or
are there other factors (or combinations thereof) to consider?

Dimensions (which affects life reduction due to self heating as well
as simply fitting the available space), lifetime (at temperature),
cost, availability, low operating temperature, maximum ripple current,
leakage current, tolerance, working voltage, surge voltage, etc.

"William Sommerwerck" wrote in
:

Does one just look for high operating temp and low ESR

Worked for me. I bet there is a more proper way to go, but I just assumed
that those two considerations would give me the best lifetime, though I also
add in a choice for a higher voltage cap because voltage headroom also
certifies an easy ride and long life.

Spehro Pefhany wrote in
:

Panasonic and Nichicon make about 20 different grades and "types" of
electrolytics. Does one just look for high operating temp and low ESR, or
are there other factors (or combinations thereof) to consider?

Dimensions (which affects life reduction due to self heating as well
as simply fitting the available space), lifetime (at temperature),
cost, availability, low operating temperature, maximum ripple current,
leakage current, tolerance, working voltage, surge voltage, etc.


Those are interesting, but I found that it's often easier to focus on a
subset. Dimensions are often dictated by the space, so I just go for higher
voltage caps which will be bigger anyway, that solves the self-heating and
the voltage overhead for safety.

Availaibility is interesting, but often the best parts get neglected till
people cry over spilt unobtainium. Although they cost a bit more, it might be
best to go for them anyway, that way suppliers will take care of
availability. The best way to make unobtainium is the slow fission of
amnesium...

One thing I never remember well is the correlation between ripple current and
ESR, though I imagine low ESR types tolerate ripple currents better because
they will dissipate less power per amp of ripple.

On Thu, 07 May 2009 13:59:30 -0500, Lostgallifreyan
wrote:

Spehro Pefhany wrote in
:

Panasonic and Nichicon make about 20 different grades and "types" of
electrolytics. Does one just look for high operating temp and low ESR, or
are there other factors (or combinations thereof) to consider?

Dimensions (which affects life reduction due to self heating as well
as simply fitting the available space), lifetime (at temperature),
cost, availability, low operating temperature, maximum ripple current,
leakage current, tolerance, working voltage, surge voltage, etc.


Those are interesting, but I found that it's often easier to focus on a
subset. Dimensions are often dictated by the space, so I just go for higher
voltage caps which will be bigger anyway, that solves the self-heating and
the voltage overhead for safety.

Maybe for replacement use, where someone else has already crunched the
numbers.

Availaibility is interesting, but often the best parts get neglected till
people cry over spilt unobtainium.

I always try to use the most bog-standard, inexpensive, available and
reliable parts. There's more than enough excitement to be had in the
parts that really ought to be oddball.

Although they cost a bit more, it might be
best to go for them anyway, that way suppliers will take care of
availability. The best way to make unobtainium is the slow fission of
amnesium...

I'm not eager to take dusty stock off the hands of distributors under
most conditions.

One thing I never remember well is the correlation between ripple current and
ESR, though I imagine low ESR types tolerate ripple currents better because
they will dissipate less power per amp of ripple.

Yes, all other things being equal. One thing that's not obvious unless
you study the data is that self-heating, even when within the
allowable ripple current rating, can dramatically reduce the lifetime
of the capacitors (and often also the product).

Spehro Pefhany wrote in
:

I always try to use the most bog-standard, inexpensive, available and
reliable parts. There's more than enough excitement to be had in the
parts that really ought to be oddball.


That's true, though I sometimes analogise with the old batteries, SP2 and
HP2, in the UK, they were the safe middle ground of zinc carbon types, with
all kinds of esoterica lingering from portable valve radios and specialised
photoflash types. SP was standard power, HP, high power. SP was cheaper. Both
endured (even now, I think) because people realised it was often better to
pay more for HP as you usually got better bang per buck that way. I sometimes
think the electronics industry is like buyers who all go for SP because it's
cheaper, and still middle ground, and who come to mourn the demise of HP and
likely only have themselves to blame.

I think just edging a tier upward in performance is worth the cost. For one
thing it is a good way to beat the disability culture that besets
manufacturing now, and if unchecked, will result in government pressures to
reduce inefficiency and waste. I suspect most makers would rather jump than
be pushed, especially if jumping early gives them something to help advertise
the product's reliability.

Although they cost a bit more, it might be
best to go for them anyway, that way suppliers will take care of
availability. The best way to make unobtainium is the slow fission of
amnesium...

I'm not eager to take dusty stock off the hands of distributors under
most conditions.


Nor me, but by then it's usually too late anyway. Dusty amnesium is about as
appetising as sweaty gelignite.

Lostgallifreyan wrote in
:

disability

Strange typo... meant 'disposability'

And also for completeness and no good reason whatsoever, I wanted to mention
that bell boxes and bike lights were also a source of some very bizarre and
esoteric 'standard' batteries best avoided, now seen in museums, probably..

In article , Dave Platt
writes

One manufacturer was citing a "50,000
hour" lifetime figure on the motherboard carton

Are you sure there isn't a microdot in the small print with the words
"electrolytic capacitors excepted" printed on it?

--
(\__/)
(='.'=) Bunny says Windows 7 is Vi$ta reloaded.
(")_(") http://imgs.xkcd.com/comics/windows_7.png

Mike Tomlinson wrote:
In article , Dave Platt
writes

One manufacturer was citing a "50,000
hour" lifetime figure on the motherboard carton

Are you sure there isn't a microdot in the small print with the words
"electrolytic capacitors excepted" printed on it?


"lifetime" is a word of dubious interpretation. Does it mean that it
won't break in that time, that it can be repaired in that time if it
does break, or something else?

If they claimed an MTBF of 50,000 hours, that would be different.

Sylvia.

Mike Tomlinson wrote:

In article , Dave Platt
writes

One manufacturer was citing a "50,000
hour" lifetime figure on the motherboard carton

Are you sure there isn't a microdot in the small print with the words
"electrolytic capacitors excepted" printed on it?

After the bad caps debacle one manufacturer, it might be Gigabyte, moved
to the OSCON type in which case it may very well be true.

Graham

On Fri, 08 May 2009 22:04:27 +1000, Sylvia Else
wrote:

Mike Tomlinson wrote:
In article , Dave Platt
writes

One manufacturer was citing a "50,000
hour" lifetime figure on the motherboard carton

Are you sure there isn't a microdot in the small print with the words
"electrolytic capacitors excepted" printed on it?


"lifetime" is a word of dubious interpretation. Does it mean that it
won't break in that time, that it can be repaired in that time if it
does break, or something else?

If they claimed an MTBF of 50,000 hours, that would be different.

Sylvia.

AFAIUI, MTBF typically applies only to the flat part at the bottom of
teh bathtub curve. They conveniently hack off the infantile failures
at the left and the increasing failures as the useful life expires on
the right. IOW, a product can have a much higher MTFB than the time it
takes to wear out.

Also, 50,000 hours 24/7 is only 5.7 years, which is more-or-less what
you'd expect out of a motherboard.

Spehro Pefhany wrote:

Sylvia Else wrote:
Mike Tomlinson wrote:
Dave Platt writes

One manufacturer was citing a "50,000
hour" lifetime figure on the motherboard carton

Are you sure there isn't a microdot in the small print with the words
"electrolytic capacitors excepted" printed on it?


"lifetime" is a word of dubious interpretation. Does it mean that it
won't break in that time, that it can be repaired in that time if it
does break, or something else?

If they claimed an MTBF of 50,000 hours, that would be different.


AFAIUI, MTBF typically applies only to the flat part at the bottom of
teh bathtub curve. They conveniently hack off the infantile failures
at the left and the increasing failures as the useful life expires on
the right. IOW, a product can have a much higher MTFB than the time it
takes to wear out.

Also, 50,000 hours 24/7 is only 5.7 years, which is more-or-less what
you'd expect out of a motherboard.

And if you run a 105C cap at 40C you'll get ~ 85 times the datasheet
lifetime. So a 2,000 hr 105C cap would last over 19 years. Watch the ripple
current of course !

Interesting point there. One decoupling cap on a mobo of mine near the
graphics card slot was visibly bulged whereas others weren't. I imagine it
was hot air being blown onto it by the GPU fan.

Graham

In article , Spehro Pefhany
writes

Also, 50,000 hours 24/7 is only 5.7 years, which is more-or-less what
you'd expect out of a motherboard.

Not from electrolytic caps, which was kind of the point. Even Panasonic
specify only 10k hours for their top of the range electros.

--
(\__/)
(='.'=) Bunny says Windows 7 is Vi$ta reloaded.
(")_(") http://imgs.xkcd.com/comics/windows_7.png

On Fri, 8 May 2009 15:08:31 +0100, Mike Tomlinson
wrote:

In article , Spehro Pefhany
writes

Also, 50,000 hours 24/7 is only 5.7 years, which is more-or-less what
you'd expect out of a motherboard.

Not from electrolytic caps, which was kind of the point. Even Panasonic
specify only 10k hours for their top of the range electros.

I guess that would be a rather serious problem if the temperature
inside your computer case averaged 105°C = 221°F.

http://www.loc.gov/rr/scitech/mysteries/friedegg.html

In article , Spehro Pefhany
writes

I guess that would be a rather serious problem if the temperature
inside your computer case averaged 105°C = 221°F.

Seen a modern mainboard recently? Voltage regulation MOSFETs with
heatsinks on, some with their own extractor fans? Heat coupled to the
capacitors by a few millimetres of thick copper PCB trace for excellent
heat conduction?

--
(\__/)
(='.'=) Bunny says Windows 7 is Vi$ta reloaded.
(")_(") http://imgs.xkcd.com/comics/windows_7.png

Also, 50,000 hours 24/7 is only 5.7 years, which is more-or-less what
you'd expect out of a motherboard.

Not from electrolytic caps, which was kind of the point. Even Panasonic
specify only 10k hours for their top of the range electros.

But isn't that at "high" temperatures, or some other extreme operating
condition?

On Fri, 8 May 2009 15:37:26 +0100, Mike Tomlinson
wrote:

In article , Spehro Pefhany
writes

I guess that would be a rather serious problem if the temperature
inside your computer case averaged 105°C = 221°F.

Seen a modern mainboard recently?

Certainly.

Voltage regulation MOSFETs with
heatsinks on, some with their own extractor fans? Heat coupled to the
capacitors by a few millimetres of thick copper PCB trace for excellent
heat conduction?

Have you put a thermocouple on the capacitors?

Mike Tomlinson wrote:

Spehro Pefhany writes

Also, 50,000 hours 24/7 is only 5.7 years, which is more-or-less what
you'd expect out of a motherboard.

Not from electrolytic caps, which was kind of the point. Even Panasonic
specify only 10k hours for their top of the range electros.

AT RATED TEMP and RATED RIPPLE CURRENT. Rarely found in combination except
by bad design, and it does happen sometimes.

You can get far better by de-rating. Rule of thumb is to reduce the temp
from rated value by 10C and double the lifetime etc etc.

Graham

William Sommerwerck wrote:

Also, 50,000 hours 24/7 is only 5.7 years, which is more-or-less what
you'd expect out of a motherboard.

Not from electrolytic caps, which was kind of the point. Even Panasonic
specify only 10k hours for their top of the range electros.

But isn't that at "high" temperatures, or some other extreme operating
condition?

Yes.

Grham

Mike Tomlinson wrote:

Spehro Pefhany writes

I guess that would be a rather serious problem if the temperature
inside your computer case averaged 105°C = 221°F.

Seen a modern mainboard recently? Voltage regulation MOSFETs with
heatsinks on, some with their own extractor fans? Heat coupled to the
capacitors by a few millimetres of thick copper PCB trace for excellent
heat conduction?

Point 1: You can ventilate your case and CPU far better than 'normal'
methods.

Point 2: leave the side panels off like I tend to do !

Graham

Spehro Pefhany wrote:

Mike Tomlinson wrote:
Spehro Pefhany writes

I guess that would be a rather serious problem if the temperature
inside your computer case averaged 105°C = 221°F.

Seen a modern mainboard recently?

Certainly.

Voltage regulation MOSFETs with
heatsinks on, some with their own extractor fans? Heat coupled to the
capacitors by a few millimetres of thick copper PCB trace for excellent
heat conduction?

Have you put a thermocouple on the capacitors?

You need a themocouple and a suitable meter for that ! ;~)

Graham

Sylvia Else wrote:
Mike Tomlinson wrote:
In article , Dave Platt
writes

One manufacturer was citing a "50,000
hour" lifetime figure on the motherboard carton

Are you sure there isn't a microdot in the small print with the words
"electrolytic capacitors excepted" printed on it?


"lifetime" is a word of dubious interpretation. Does it mean that it
won't break in that time, that it can be repaired in that time if it
does break, or something else?

If they claimed an MTBF of 50,000 hours, that would be different.

****, I'd generally be happy with 2000 hours MTBF.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

Point 2: Leave the side panels off like I tend to do!

I do, but that's mostly to make it easy to perform full backups. The machine
run coolers, though it spews more RF, which keeps atomic clocks in the same
room from synching.

By the way, check the CPU cooler occasionally. Mine hadn't been cleaned
since I bought the computer over eight years ago, and you cannot believe how
clogged with shmutz the heat sink was.

William Sommerwerck wrote:

Point 2: Leave the side panels off like I tend to do!

I do, but that's mostly to make it easy to perform full backups. The machine
run coolers, though it spews more RF, which keeps atomic clocks in the same
room from synching.

Not a problem for me.


By the way, check the CPU cooler occasionally. Mine hadn't been cleaned
since I bought the computer over eight years ago, and you cannot believe how
clogged with shmutz the heat sink was.

I clean them moderately regularly. Plus I don't operate in a very dusty
environment.

Gragam

By the way, check the CPU cooler occasionally. Mine
hadn't been cleaned since I bought the computer over
eight years ago, and you cannot believe how clogged
with shmutz the heat sink was.

I clean them moderately regularly. Plus I don't operate
in a very dusty environment.

Nor do I. This wasn't dust -- it was more like gobs of sub-microscopic
carbon particles.

William Sommerwerck wrote:

By the way, check the CPU cooler occasionally. Mine
hadn't been cleaned since I bought the computer over
eight years ago, and you cannot believe how clogged
with shmutz the heat sink was.

I clean them moderately regularly. Plus I don't operate
in a very dusty environment.

Nor do I. This wasn't dust -- it was more like gobs of sub-microscopic
carbon particles.

Never seen that. On the CPU cooler itself you mean ?

Grham

Eeyore wrote:



Mike Tomlinson wrote:

In article , Dave Platt
writes

One manufacturer was citing a "50,000
hour" lifetime figure on the motherboard carton

Are you sure there isn't a microdot in the small print with the words
"electrolytic capacitors excepted" printed on it?

After the bad caps debacle one manufacturer, it might be Gigabyte,
moved to the OSCON type in which case it may very well be true.

Graham

Yes ! Gigabyte got bitten hard by that and the fake motherboard scam.

--
Best Regards:
Baron.

On Fri, 08 May 2009 17:12:11 +0100, Eeyore
wrote:



Spehro Pefhany wrote:

Mike Tomlinson wrote:
Spehro Pefhany writes

I guess that would be a rather serious problem if the temperature
inside your computer case averaged 105°C = 221°F.

Seen a modern mainboard recently?

Certainly.

Voltage regulation MOSFETs with
heatsinks on, some with their own extractor fans? Heat coupled to the
capacitors by a few millimetres of thick copper PCB trace for excellent
heat conduction?

Have you put a thermocouple on the capacitors?

You need a themocouple and a suitable meter for that ! ;~)

Graham

Really? ;-)

Of course many, if not most, portable multimeters have type K
thermocouple inputs (of dubious accuracy, but good enough for this
sort of thing) and many are supplied with a bead thermocouple.

On Sat, 09 May 2009 02:16:42 +1000, Bob Larter
wrote:

Sylvia Else wrote:
Mike Tomlinson wrote:
In article , Dave Platt
writes

One manufacturer was citing a "50,000
hour" lifetime figure on the motherboard carton

Are you sure there isn't a microdot in the small print with the words
"electrolytic capacitors excepted" printed on it?


"lifetime" is a word of dubious interpretation. Does it mean that it
won't break in that time, that it can be repaired in that time if it
does break, or something else?

If they claimed an MTBF of 50,000 hours, that would be different.

****, I'd generally be happy with 2000 hours MTBF.

Less than 12 weeks? You have a bright potential future with Samsung,
HP etc.

Spehro Pefhany wrote:

Eeyore wrote:
Spehro Pefhany wrote:
Mike Tomlinson wrote:
Spehro Pefhany writes

I guess that would be a rather serious problem if the temperature
inside your computer case averaged 105°C = 221°F.

Seen a modern mainboard recently?

Certainly.

Voltage regulation MOSFETs with
heatsinks on, some with their own extractor fans? Heat coupled to the
capacitors by a few millimetres of thick copper PCB trace for excellent
heat conduction?

Have you put a thermocouple on the capacitors?

You need a themocouple and a suitable meter for that ! ;~)

Graham

Really? ;-)

Of course many, if not most, portable multimeters have type K
thermocouple inputs (of dubious accuracy, but good enough for this
sort of thing) and many are supplied with a bead thermocouple.

Funnily enough, often some of the cheapest ones have the thermocouple input but
I used to keep a supply of type-K themocoouples anyway. I like keeping an eye
on temps.

Graham

I clean them moderately regularly. Plus I don't operate
in a very dusty environment.

Nor do I. This wasn't dust -- it was more like gobs of
sub-microscopic carbon particles.

Never seen that. On the CPU cooler itself you mean?

On the heat-sink. It reminded me of the black stuff that comes off a CRT
faceplate. Only a lot more.

On May 7, 6:53*am, DaveC wrote:
Today I ordered electrolytic caps. It was frustrating. I had
planned to get
the best low-ESR replacements for all the caps in some switching
power
supplies. I discovered how limited any one manufacturer's low-ESR
catalog is.
Many of what I needed (none of which seem to me to be esoteric
values) were
not available. A couple of times I had to leave a particular
manufacturer's
catalog altogether to find a value.

Which brings me to my question. I was trying to get all Panasonic
FM-series
(hi-temp, low-ESR) caps. I've heard good things about Panasonic's
caps, but
being forced to another brand I has no idea of comparable quality.
(This, at
Digi-Key and Mouser.)

Also, How important is the type of electrolyte? I've read that low-
ESR caps
are frequently made with water-based electrolyte whereas non-water-
based
formulae cannot give low ESR value.

The qualities of caps (ie, hi-ripple, hi-temp, low-ESR, etc.) are
frequently
discussed on electronics forum, but I haven't seen the different
manufacturers compared.

How do the quality of caps compare by

Nichicon
Panasonic
Vishay / Sprague
Mallory
Rubycon
United Chemi-Con
Cornell Dublier
Xicon

Feel free to add to the list, praise, trash, and/or list in order
of your
preference. Extra credit for essays on why you like / hate / prefer
a brand
or series of caps.

Thanks,
--
DaveC

I buy the replacement parts at a Hollywood dub house. Last year I
bought 14.000 'lytics , 10,000 installed by 3 of us. My first choice
in Panasonic FM but the selection isn't as wide as the second choice
of FC caps. If I run into a physical size problem Nichicon PW series
often helps. For surface mount first choice is Panasonic FK and
sometimes HC series. If you're doing this a lot like we are, Metcal
soldering irons are HIGHLY recommended. The STTC-126 tip (700 F 30
degree bent tip) is really good for clearing stubborn holes - usually
ground planes with lousy thermal reliefs. A lifted pad is a very rare
event with a good soldering iron.

100uf 25V (most common value for us) cost 20 cents in 1's 10.28 / 100
but are only $57.54 / 1000. I try for 1000s whenever possible.

G²