laptop power fault: compaq presario C300EA

[Conor]

[email protected] wrote in [email protected]:


Two light tan, near left bottom corner, ~1/4 distance to top edge and ~1/8
distance to right edge, with brown polarity bands, opposite polarity, bands
out.

Without part numbers, it's meaningless.

I see at least 3 on the bottom view, one near the top edge center and two
near the bottom edge center, partially hidden by a wiring bundle.

Any cap over 10 uF will probably be electrolytic.

Wrong.

 

[David]

Without part numbers, it's meaningless.


Wrong.

Actually most laptops use tantalum polarized capacitors
which are a type of electrolytic capacitor. What they avoid
are the more common aluminum electrolytic capacitors.
Ceramics are available in low voltages at quite high
capacitance values, but I have yet to see one over 10 uF.

David

 

[Conor]

Actually most laptops use tantalum polarized capacitors
which are a type of electrolytic capacitor. What they avoid
are the more common aluminum electrolytic capacitors.
Ceramics are available in low voltages at quite high
capacitance values, but I have yet to see one over 10 uF.

Beat me to it. Was just going to post a link to a piccy of a tantalum.

 

[[email protected]]

Actually most laptops use tantalum polarized capacitors
which are a type of electrolytic capacitor. What they avoid
are the more common aluminum electrolytic capacitors.
Ceramics are available in low voltages at quite high
capacitance values, but I have yet to see one over 10 uF.

David

Nope. There are wet tantalum capacitors (that exist), but nobody uses
those in laptops. In laptops you find surface mount dry tantalums
among other solid types, not electrolytic at all... again, this refers
to semi-modern laptops, not something really ancient.

 

[[email protected]]

[email protected] wrote in [email protected]:


Two light tan, near left bottom corner, ~1/4 distance to top edge and ~1/8
distance to right edge, with brown polarity bands, opposite polarity, bands
out.

?? You have not indicated any electrolytic caps (but that's to be
expected since there aren't any).

There are almost certainly others but resolution insufficient.

Other caps yes, but not electrolytic. I made that picture on a
scanner, how high a resolution can you handle?
Think these are 600DPI, roughly 6000x6000 res. so I'd recommend not
trying to open them directly in a web browser.
~ 11MB Top Scan http://69.36.166.207/usr_1034/Top.jpg
~ 7MB Bottom http://69.36.166.207/usr_1034/Bottom.jpg

I see at least 3 on the bottom view, one near the top edge center and two
near the bottom edge center, partially hidden by a wiring bundle.

Caps yes, tantalum or other solid types like niobium. I suppose I
should clarify that sometimes I'll see people calling solid
capacitors, "solid electrolytic" but that is a misnomer, electrolytic
implies a liquid electrolyte. Perhaps they really meant solid
aluminum (can).

Any cap over 10 uF will probably be electrolytic.

Practically all (on that example board scan) that aren't ceramic are
over 10uF, none of which are electrolytic. Certainly years ago this
would have been near impossible at any reasonable price, but great
gains have been made in solid capacitors in the last 8 years or so,
give or take.

 

[bz]

[email protected] wrote in [email protected]:

Nope. There are wet tantalum capacitors (that exist), but nobody uses
those in laptops. In laptops you find surface mount dry tantalums
among other solid types, not electrolytic at all... again, this refers
to semi-modern laptops, not something really ancient.

http://en.wikipedia.org/wiki/Electrolytic_capacitor

Take a look at the pictures.
http://en.wikipedia.org/wiki/File:Cap-elko-smd-polarity.jpg

Check your laptop and make sure you DON'T have any of the mugs in the shot.

If you are saying that 'modern' laptops don't have
http://en.wikipedia.org/wiki/File:Capacitors_electrolytic.jpg
then you are right but modern laptops DO have other types of electrolytic.

The defining part that makes a capacitor an electrolytic is the presence of
an electrolyte and the electro-chemical reaction that forms one of the
electrodes in 'very close proximity' to the metal electrode which can be
aluminum or tantalum or some other metal.

I used to make ceramic capacitors, so I am not really an expert on
electrolytic but you seem to have a mistaken idea as to what constitutes an
'electrolytic'.




--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

[email protected] remove ch100-5 to avoid spam trap

 

[Jerry Peters]

Without part numbers, it's meaningless.


Wrong.

Any cap over .1 uF or so will probably be an electro.

Jerry

 

[Jerry Peters]

Nope. There are wet tantalum capacitors (that exist), but nobody uses
those in laptops. In laptops you find surface mount dry tantalums
among other solid types, not electrolytic at all... again, this refers
to semi-modern laptops, not something really ancient.

A tatalum cap is a type of electrolytic. Specifically the dielectric
is formed by electro-chemical action.

Jerry

 

[Jerry Peters]

Now you know one of the reasons why they don't typically put
electrolytics in laptops anymore. I never suggested no old laptop
ever had any, but this is a pretty modern laptop not some ancient Dell.

Considering the size it was probably a tantalum, which is a *type* of
electrolytic capacitor.

Considering the Dell is by now probably 12 years old I'd say it's
doing quite well.

Jerry

 

[krw]

Any cap over .1 uF or so will probably be an electro.

Nah, ceramics up to (and including) 10uF are common. I use bunches
of 'em. There's quite an overlap (both have their use).

 

[Baron]

I have, several times. They use mostly if not entirely solid,
(usually chip) caps, and ceramics with good reason. Electrolytics
wear out too fast inside modern laptops because of the elevated temps,
not to mention their height being a problem when engineering something
as thin as reasonably possible.

Here's a picture of both sides of a quite typical HP laptop mainboard,
under two years old and quite similar to what they're still using.
Point out the electrolytic caps on it and BTW, this is the whole thing
there is no separate power board:

http://img242.imageshack.us/img242/5075/topsmfz3.jpg

There are six visible in fz3.jpg

http://img243.imageshack.us/img243/961/bottomsmsf5.jpg

and four, possibly five in sf5.jpg

The solid caps are black, and yellow.

Those two are tants and I think the others are too !

 

[Baron]

By that I meant no internal power converter board that's separate, it
does have a separate input jack board (also without caps, it's only a
strip big enough to hold a couple jacks), and the brick AC-DC adapter
separate as with practically all laptops in the last several years.

There is a switch mode PSU in the first picture bottom right hand side
along with its four caps and inductor !

 

[[email protected]]

[email protected] wrote in [email protected]:


http://en.wikipedia.org/wiki/Electrolytic_capacitor

Take a look at the pictures.http://en.wikipedia.org/wiki/File:Cap-elko-smd-polarity.jpg

Check your laptop and make sure you DON'T have any of the mugs in the shot.

If you are saying that 'modern' laptops don't havehttp://en.wikipedia.org/wiki/File:Capacitors_electrolytic.jpg
then you are right but modern laptops DO have other types of electrolytic..

The defining part that makes a capacitor an electrolytic is the presence of
an electrolyte and the electro-chemical reaction that forms one of the
electrodes in 'very close proximity' to the metal electrode which can be
aluminum or tantalum or some other metal.

I used to make ceramic capacitors, so I am not really an expert on
electrolytic but you seem to have a mistaken idea as to what constitutes an
'electrolytic'.

--
bz      73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

[email protected]   remove ch100-5 to avoid spam trap

This is a good example of why we can't trust the encyclopedia that
anyone can edit.
The pictured caps aren't all electrolytic. The first two from the
left are, and the rest are not (not 100% sure about the 2nd from the
end on the right side).

Electrolytic requires liquid electrolyte.

 

[[email protected]]

A tatalum cap is a type of electrolytic. Specifically the dielectric
is formed by electro-chemical action.

        Jerry

There are types of wet tantalums that are electrolytic caps, but the
solid tantalums are not. Where are these urban myths coming from?

 

[[email protected]]

Any cap over .1 uF or so will probably be an electro.

        Jerry

No. You can easily see on cap manufacturer datasheets that almost all
chip caps are not electrolytic, and even ceramics now go up to 20uF.
The chip tantalum, niobium, and other solid polymer caps you'll often
find in laptops typically go up to about 470uF, there have been great
strides in the past few years in this respect.

 

[[email protected]]

Considering the size it was probably a tantalum, which is a *type* of
electrolytic capacitor.

Considering the Dell is by now probably 12 years old I'd say it's
doing quite well.

        Jerry

Yes that's a great life for a laptop but at what point do you have to
build your own battery packs because even the new stock is several
years old stock?

It was not likely a tantalum, you do realize they explode, not vent,
when shorted or reverse polarity? Not sure about the wet ones
(probably not), but there's no reason they'd use something that exotic
on the DC power inlet filter.

 

[[email protected]]

[email protected] wrote in [email protected]:


http://en.wikipedia.org/wiki/Electrolytic_capacitor

Take a look at the pictures.http://en.wikipedia.org/wiki/File:Cap-elko-smd-polarity.jpg

Check your laptop and make sure you DON'T have any of the mugs in the shot.

If you are saying that 'modern' laptops don't havehttp://en.wikipedia.org/wiki/File:Capacitors_electrolytic.jpg
then you are right but modern laptops DO have other types of electrolytic..

The defining part that makes a capacitor an electrolytic is the presence of
an electrolyte and the electro-chemical reaction that forms one of the
electrodes in 'very close proximity' to the metal electrode which can be
aluminum or tantalum or some other metal.

I used to make ceramic capacitors, so I am not really an expert on
electrolytic but you seem to have a mistaken idea as to what constitutes an
'electrolytic'.

http://www.hitachi-aic.com/english/products/capacitors/tantal/k_chip.html

Not electrolyte in the conventional sense of the word.
While we could (and are) technically arguing about what constitutes an
electrolyte, the majority of the capacitor industry is calling
electrolytic caps those that have a liquid solvent. A few may have
caused confusion because when they claim electrolytic they are not
talking about the same thing, they are only referring to the
manufacturing process in which they grow the oxide layer on the metal
using electrolyte which is not put in the capacitor as a finished
product.

 

[bz]

[email protected] wrote in [email protected]:

.....

This is a good example of why we can't trust the encyclopedia that
anyone can edit.
The pictured caps aren't all electrolytic. The first two from the
left are, and the rest are not (not 100% sure about the 2nd from the
end on the right side).

Electrolytic requires liquid electrolyte.

READ the article.
http://en.wikipedia.org/wiki/Electrolytic_capacitor
I see no mistakes in it.

YOU are mistaken in your idea that electrolytics require a liquid
electrolyte.

You will find that the essential action that produces an electrolytic is the
formation of the dielectric 'oxide' layer by the electrochemical action.

There is no point in arguing over a definition. One either accept the
commonly used definition and communicates with the world or insists on using
a different definition and is frequently misunderstood.

Electrolyte: An electrolyte is a substance that will dissociate into ions in
solution and acquire the capacity to conduct electricity. The electrolytes
include sodium, potassium, chloride, calcium and phosphate. Informally,
called lytes. (The clue to the word electrolyte is in the lyte which comes
from the Greek lytos meaning that may be dissolved.)
[unquote]

If you look up "solid electrolyte" you will find that there are many
compounds that are considered electrolytes that contain no water and some are
even solids.

The SM chip left of C34 is probably an electrolytic, as are the two above the
marking C518 on the topside picture. On the bottom, the two chips I mentioned
before are just to the right and above the marking R678, another is above the
marking 07/03/17 on the heat pipe in your bottom picture.

But we have wandered far afield of helping the OP fix the problem with his
laptop.





--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

[email protected] remove ch100-5 to avoid spam trap

 

[[email protected]]

[email protected] wrote in [email protected]:

....

This is a good example of why we can't trust the encyclopedia that
anyone can edit.
The pictured caps aren't all electrolytic.  The first two from the
left are, and the rest are not (not 100% sure about the 2nd from the
end on the right side).

Electrolytic requires liquid electrolyte.

READ the article.http://en.wikipedia.org/wiki/Electrolytic_capacitor
I see no mistakes in it.

YOU are mistaken in your idea that electrolytics require a liquid
electrolyte.

You will find that the essential action that produces an electrolytic is the
formation of the dielectric 'oxide' layer by the electrochemical action.

There is no point in arguing over a definition. One either accept the
commonly used definition and communicates with the world or insists on using
a different definition and is frequently misunderstood.

Electrolyte: An electrolyte is a substance that will dissociate into ionsin
solution and acquire the capacity to conduct electricity. The electrolytes
include sodium, potassium, chloride, calcium and phosphate. Informally,
called lytes. (The clue to the word electrolyte is in the lyte which comes
from the Greek lytos meaning that may be dissolved.)
[unquote]

If you look up "solid electrolyte" you will find that there are many
compounds that are considered electrolytes that contain no water and someare
even solids.

The SM chip left of C34 is probably an electrolytic, as are the two abovethe
marking C518 on the topside picture. On the bottom, the two chips I mentioned
before are just to the right and above the marking R678, another is abovethe
marking 07/03/17 on the heat pipe in your bottom picture.

But we have wandered far afield of helping the OP fix the problem with his  
laptop.

--
bz      73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

[email protected]   remove ch100-5 to avoid spam trap

Electrolytic is not about manufacturing as some mistakenly claim, it
is about the end result product.

If a cap has no liquid electrolyte in it, only ignorant people would
call that electrolytic in this day and age.

 

[[email protected]]

A tatalum cap is a type of electrolytic. Specifically the dielectric
is formed by electro-chemical action.

        Jerry

Which is never what the majority calls an electrolytic cap. The
industry doesn't describe based on process, it differentiates based on
end result (except for ignorant marketing departments).