I have a Compaq laptop Model Presario, service tag C300EA that will not
start. It's this one: http://www.microdevices.lk/images/Laptop.jpg
the motherboard is an IBL30 LA-3324P and they retail for about £125.
ouch
The problem is when I plug a power supply into it and press the on/off
button the power led flashes rapidly for a few seconds and then cuts
out. I then have to wait about a minute before it will light up again.
I've tried three different power supplies, one of them coming from a
battery/voltage converter and all three power supplies produce the same
fault on the laptop so it's not the power supply. It acts the same with
or without a battery fitted. When the power supply is plugged in I did
notice the battery icon flickers all the time with no battery in.
I also connected an amp meter to the power supply and when the power
light does flicker there is virtually no current draw into the laptop.
I split the chassis to take a look and saw that the power socket wires
go straight onto the motherboard. There is no power board or
daughtercard as such..
does anyone have an idea if there's a known component that causes this
problem? or is it a case of new motherboard?
thanks for any pointers.

On Tue, 17 Feb 2009 23:35:37 -0000, "tg"
wrote:

I have a Compaq laptop Model Presario, service tag C300EA that will not
start. It's this one: http://www.microdevices.lk/images/Laptop.jpg
the motherboard is an IBL30 LA-3324P and they retail for about £125.
ouch
The problem is when I plug a power supply into it and press the on/off
button the power led flashes rapidly for a few seconds and then cuts
out. I then have to wait about a minute before it will light up again.
I've tried three different power supplies, one of them coming from a
battery/voltage converter and all three power supplies produce the same
fault on the laptop so it's not the power supply. It acts the same with
or without a battery fitted. When the power supply is plugged in I did
notice the battery icon flickers all the time with no battery in.
I also connected an amp meter to the power supply and when the power
light does flicker there is virtually no current draw into the laptop.
I split the chassis to take a look and saw that the power socket wires
go straight onto the motherboard. There is no power board or
daughtercard as such..
does anyone have an idea if there's a known component that causes this
problem? or is it a case of new motherboard?
thanks for any pointers.

Perhaps the plague? No, not THAT one, THIS one:
http://en.wikipedia.org/wiki/Capacitor_plague

Worth eyeballing since you already have the main board exposed.

--
Rich Webb Norfolk, VA

On Feb 17, 6:35*pm, "tg" wrote:
I have a Compaq laptop Model Presario, service tag C300EA that will not
start. It's this one:http://www.microdevices.lk/images/Laptop.jpg
the motherboard is an IBL30 LA-3324P and they retail for about £125.
ouch
The problem is when I plug a power supply into it and press the on/off
button the power led flashes rapidly for a few seconds and then cuts
out. I then have to wait about a minute before it will light up again.
I've tried three different power supplies, one of them coming from a
battery/voltage converter and all three power supplies produce the same
fault on the laptop so it's not the power supply. It acts the same with
or without a battery fitted. When the power supply is plugged in I did
notice the battery icon flickers all the time with no battery in.
I also connected an amp meter to the power supply and when the power
light does flicker there is virtually no current draw into the laptop.
I split the chassis to take a look and saw that the power socket wires
go straight onto the motherboard. There is no power board or
daughtercard as such..
does anyone have an idea if there's a known component that causes this
problem? or is it a case of new motherboard?
thanks for any pointers.

The symptoms suggest a short on the mainboard, the PSU aren't able to
regulate so their protection circuits are cycling them off as best
they can (at the price-point of the design).

There isn't much you can do at this point except strip the mainboard
down as much as possible. Disconnect hard drive, optical, memory, CPU
(except if you take the heatsink off and it was heatsinking the
chipset, you must put that heatsink back on and ensure it makes good
contact with the chipset still), card reader, screen, inverter board.
See if it will then "seem" (since you have no screen, watch the power
LED(s)) to stay on. It may not, without a processor and memory. If
necessary put those back in and retry. If it stays on, reconnect
screen but not the backpanel lighting inverter yet. If it turns on
and stays on, see if there is output to the screen by shining a strong
flashlight on it.

If it works this far, an inverter failure is a common cause. If it
didn't work at all up to this point, mainboard probably needs
replaced. If it works up to some point in the middle, suspect the part
(s) you added at that point. These days such a problem is typically
handled by replacing the mainboard at a repair shop, then if that
doesn't work they replace the next part and so on, till it's fixed or
the customer refuses to pay for their diagnosed problem since often
the laptop cost little more than the total repair cost.

In article , Rich Webb
says...

Perhaps the plague? No, not THAT one, THIS one:
http://en.wikipedia.org/wiki/Capacitor_plague

Worth eyeballing since you already have the main board exposed.

Didn't think laptops used electrolytic capacitors...



--
Conor

I only please one person per day. Today is not your day. Tomorrow isn't
looking good either. - Scott Adams

On Feb 17, 7:16*pm, Conor wrote:
In article , Rich Webb
says...

Perhaps the plague? No, not THAT one, THIS one:
http://en.wikipedia.org/wiki/Capacitor_plague

Worth eyeballing since you already have the main board exposed.

Didn't think laptops used electrolytic capacitors...

--
Conor

I only please one person per day. Today is not your day. Tomorrow isn't
looking good either. - Scott Adams

What did you think they used for capacitors in the power supply?

Conor wrote:
In article , Rich Webb
says...

Perhaps the plague? No, not THAT one, THIS one:
http://en.wikipedia.org/wiki/Capacitor_plague

Worth eyeballing since you already have the main board exposed.

Didn't think laptops used electrolytic capacitors...



They're surface mount, so you might not recognize them. Google is your
friend....

On Feb 18, 12:33*am, "hr(bob) "
wrote:
On Feb 17, 7:16*pm, Conor wrote:

In article , Rich Webb
says...

Perhaps the plague? No, not THAT one, THIS one:
http://en.wikipedia.org/wiki/Capacitor_plague

Worth eyeballing since you already have the main board exposed.

Didn't think laptops used electrolytic capacitors...

--
Conor

I only please one person per day. Today is not your day. Tomorrow isn't
looking good either. - Scott Adams

What did you think they used for capacitors in the power supply?

In the external AC-DC brick/wart, yes there are certainly
electrolytics.

In the interior of the notebook, only a cost-cutting design would have
any, so yes it is possible but no better notebook would have any.

On Feb 18, 1:09*am, jakdedert wrote:
Conor wrote:
In article , Rich Webb
says...

Perhaps the plague? No, not THAT one, THIS one:
http://en.wikipedia.org/wiki/Capacitor_plague

Worth eyeballing since you already have the main board exposed.

Didn't think laptops used electrolytic capacitors...

They're surface mount, so you might not recognize them. *Google is your
friend....

Yes, but, although surface mount caps can be electrolytic, in a
notebook (none at all if it's a good design), very few caps are
electrolytic, if any, except in the external brick AC-DC PSU.

In article 23249f90-8ab6-4d4f-b2d2-4de755ce52f5
@l37g2000vba.googlegroups.com, hr(bob) says...

What did you think they used for capacitors in the power supply?

Grasping at straws.

That's not remotely related to the problem is it?


--
Conor

I only please one person per day. Today is not your day. Tomorrow isn't
looking good either. - Scott Adams

In article , jakdedert
says...

Conor wrote:
In article , Rich Webb
says...

Perhaps the plague? No, not THAT one, THIS one:
http://en.wikipedia.org/wiki/Capacitor_plague

Worth eyeballing since you already have the main board exposed.

Didn't think laptops used electrolytic capacitors...



They're surface mount, so you might not recognize them. Google is your
friend....

I wouldn't buy any laptop using electrolytics other than in an external
power brick.


--
Conor

I only please one person per day. Today is not your day. Tomorrow isn't
looking good either. - Scott Adams

On Wed, 18 Feb 2009 13:54:47 -0000, Conor
wrote:

In article , jakdedert
says...

Conor wrote:
In article , Rich Webb
says...

Perhaps the plague? No, not THAT one, THIS one:
http://en.wikipedia.org/wiki/Capacitor_plague

Worth eyeballing since you already have the main board exposed.

Didn't think laptops used electrolytic capacitors...



They're surface mount, so you might not recognize them. Google is your
friend....

I wouldn't buy any laptop using electrolytics other than in an external
power brick.

The battery (or external supply) sources one voltage. The main board and
peripheral components require multiple, regulated voltages. Therefore,
somewhere there are several DC-DC converters to supply those voltages.
Those regulators will likely use tants or low ESR aluminum
electrolytics.

The OP is having problems with a "laptop power fault," therefore
*something* is likely wrong in a power stage.

Capacitors in the power stages are rather more likely to fail than
inductors or (properly rated) semiconductors, therefore it's worth
examining them for no other reason than crossing them off the list.

--
Rich Webb Norfolk, VA

In sci.electronics.repair wrote:
On Feb 18, 1:09*am, jakdedert wrote:
Conor wrote:
In article , Rich Webb
says...

Perhaps the plague? No, not THAT one, THIS one:
http://en.wikipedia.org/wiki/Capacitor_plague

Worth eyeballing since you already have the main board exposed.

Didn't think laptops used electrolytic capacitors...

They're surface mount, so you might not recognize them. *Google is your
friend....

Yes, but, although surface mount caps can be electrolytic, in a
notebook (none at all if it's a good design), very few caps are
electrolytic, if any, except in the external brick AC-DC PSU.

That's complete nonsense, of course a laptop uses electrolytics, and
lots of them to filter power throughout the unit. As jakedart said
they're surface mount units. Take one apart sometime & look.

Jerry

In sci.electronics.repair wrote:
On Feb 17, 6:35*pm, "tg" wrote:
I have a Compaq laptop Model Presario, service tag C300EA that will not
start. It's this one:http://www.microdevices.lk/images/Laptop.jpg
the motherboard is an IBL30 LA-3324P and they retail for about £125.
ouch
The problem is when I plug a power supply into it and press the on/off
button the power led flashes rapidly for a few seconds and then cuts
out. I then have to wait about a minute before it will light up again.
I've tried three different power supplies, one of them coming from a
battery/voltage converter and all three power supplies produce the same
fault on the laptop so it's not the power supply. It acts the same with
or without a battery fitted. When the power supply is plugged in I did
notice the battery icon flickers all the time with no battery in.
I also connected an amp meter to the power supply and when the power
light does flicker there is virtually no current draw into the laptop.
I split the chassis to take a look and saw that the power socket wires
go straight onto the motherboard. There is no power board or
daughtercard as such..
does anyone have an idea if there's a known component that causes this
problem? or is it a case of new motherboard?
thanks for any pointers.

The symptoms suggest a short on the mainboard, the PSU aren't able to
regulate so their protection circuits are cycling them off as best
they can (at the price-point of the design).

There isn't much you can do at this point except strip the mainboard
down as much as possible. Disconnect hard drive, optical, memory, CPU
(except if you take the heatsink off and it was heatsinking the
chipset, you must put that heatsink back on and ensure it makes good
contact with the chipset still), card reader, screen, inverter board.
See if it will then "seem" (since you have no screen, watch the power
LED(s)) to stay on. It may not, without a processor and memory. If
necessary put those back in and retry. If it stays on, reconnect
screen but not the backpanel lighting inverter yet. If it turns on
and stays on, see if there is output to the screen by shining a strong
flashlight on it.

If it works this far, an inverter failure is a common cause. If it
didn't work at all up to this point, mainboard probably needs
replaced. If it works up to some point in the middle, suspect the part
(s) you added at that point. These days such a problem is typically
handled by replacing the mainboard at a repair shop, then if that
doesn't work they replace the next part and so on, till it's fixed or
the customer refuses to pay for their diagnosed problem since often
the laptop cost little more than the total repair cost.

Had a problem like that with an old Dell laptop. Measuring the
resistance across the power input jack showed a direct short. After
disassembling the unit I found an electrolytic across the power lines,
after the rf filter & fuse that was shorted. Removed it and the laptop
now works fine (so much for no electrolytics in laptops).

Jerry

On Wed, 18 Feb 2009 13:54:47 -0000, Conor wrote:

In article , jakdedert
says...

Conor wrote:
In article , Rich Webb
says...

Perhaps the plague? No, not THAT one, THIS one:
http://en.wikipedia.org/wiki/Capacitor_plague

Worth eyeballing since you already have the main board exposed.

Didn't think laptops used electrolytic capacitors...



They're surface mount, so you might not recognize them. Google is your
friend....

I wouldn't buy any laptop using electrolytics other than in an external
power brick.

I guess you'll never own one then ....

On Feb 18, 6:20*pm, Jerry Peters wrote:
In sci.electronics.repair wrote:
On Feb 18, 1:09*am, jakdedert wrote:
Conor wrote:
In article , Rich Webb
says...

Perhaps the plague? No, not THAT one, THIS one:
http://en.wikipedia.org/wiki/Capacitor_plague

Worth eyeballing since you already have the main board exposed.

Didn't think laptops used electrolytic capacitors...

They're surface mount, so you might not recognize them. *Google is your
friend....

Yes, but, although surface mount caps can be electrolytic, in a
notebook (none at all if it's a good design), very few caps are
electrolytic, if any, except in the external brick AC-DC PSU.

That's complete nonsense, of course a laptop uses electrolytics, and
lots of them to filter power throughout the unit. As jakedart said
they're surface mount units. Take one apart sometime & look.

* * * * Jerry

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

The solid caps are black, and yellow. The ceramics of course are tan.
There are plenty more pictures from 3rd parties available with a
google search if you can't accept the above pics are typical:
http://images.google.com/images?q=laptop+mainboard

On Feb 19, 12:19*am, wrote:
... BTW, this is the whole thing
there is no separate power board:

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.

On Feb 18, 9:06*pm, rebel wrote:
On Wed, 18 Feb 2009 13:54:47 -0000, Conor wrote:
In article , jakdedert
says...

Conor wrote:
In article , Rich Webb
says...

Perhaps the plague? No, not THAT one, THIS one:
http://en.wikipedia.org/wiki/Capacitor_plague

Worth eyeballing since you already have the main board exposed.

Didn't think laptops used electrolytic capacitors...

They're surface mount, so you might not recognize them. *Google is your
friend....

I wouldn't buy any laptop using electrolytics other than in an external
power brick.

I guess you'll never own one then ....

False. The only place a typical modern laptop has electrolytic
capacitors is in the AC-DC brick, and there typically 2 or 3. There
might be one of those old build-your-own PCChips kits still running
that has 'lytics, but that's because PCChips makes cheap junk and it
was huge for what it was, IIRC.

On Feb 18, 6:25*pm, Jerry Peters wrote:
In sci.electronics.repair wrote:
On Feb 17, 6:35*pm, "tg" wrote:
I have a Compaq laptop Model Presario, service tag C300EA that will not
start. It's this one:http://www.microdevices.lk/images/Laptop.jpg
the motherboard is an IBL30 LA-3324P and they retail for about £125.
ouch
The problem is when I plug a power supply into it and press the on/off
button the power led flashes rapidly for a few seconds and then cuts
out. I then have to wait about a minute before it will light up again.
I've tried three different power supplies, one of them coming from a
battery/voltage converter and all three power supplies produce the same
fault on the laptop so it's not the power supply. It acts the same with
or without a battery fitted. When the power supply is plugged in I did
notice the battery icon flickers all the time with no battery in.
I also connected an amp meter to the power supply and when the power
light does flicker there is virtually no current draw into the laptop.
I split the chassis to take a look and saw that the power socket wires
go straight onto the motherboard. There is no power board or
daughtercard as such..
does anyone have an idea if there's a known component that causes this
problem? or is it a case of new motherboard?
thanks for any pointers.

The symptoms suggest a short on the mainboard, the PSU aren't able to
regulate so their protection circuits are cycling them off as best
they can (at the price-point of the design).

There isn't much you can do at this point except strip the mainboard
down as much as possible. *Disconnect hard drive, optical, memory, CPU
(except if you take the heatsink off and it was heatsinking the
chipset, you must put that heatsink back on and ensure it makes good
contact with the chipset still), card reader, screen, inverter board.
See if it will then "seem" (since you have no screen, watch the power
LED(s)) to stay on. *It may not, without a processor and memory. *If
necessary put those back in and retry. *If it stays on, reconnect
screen but not the backpanel lighting inverter yet. *If it turns on
and stays on, see if there is output to the screen by shining a strong
flashlight on it.

If it works this far, an inverter failure is a common cause. *If it
didn't work at all up to this point, mainboard probably needs
replaced. *If it works up to some point in the middle, suspect the part
(s) you added at that point. *These days such a problem is typically
handled by replacing the mainboard at a repair shop, then if that
doesn't work they replace the next part and so on, till it's fixed or
the customer refuses to pay for their diagnosed problem since often
the laptop cost little more than the total repair cost.

Had a problem like that with an old Dell laptop. Measuring the
resistance across the power input jack showed a direct short. After
disassembling the unit I found an electrolytic across the power lines,
after the rf filter & fuse that was shorted. Removed it and the laptop
now works fine (so much for no electrolytics in laptops).

* * * * Jerry

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.

wrote in news:f8d97d59-d8dc-4594-8cd4-
:

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

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.

There are almost certainly others but resolution insufficient.

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.




--
bz 73 de N5BZ k

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

remove ch100-5 to avoid spam trap

In article , rebel says...

I wouldn't buy any laptop using electrolytics other than in an external
power brick.

I guess you'll never own one then ....

There speaks someone who knows **** all about electronics. If you did,
you'd know why electrolytic caps in a laptop is generally considered "A
Bad Idea".


--
Conor

I only please one person per day. Today is not your day. Tomorrow isn't
looking good either. - Scott Adams

In article 39, bz
says...

wrote in news:f8d97d59-d8dc-4594-8cd4-
:

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

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.


--
Conor

I only please one person per day. Today is not your day. Tomorrow isn't
looking good either. - Scott Adams

"Conor" wrote in message
...
In article
39, bz
says...

wrote in
news:f8d97d59-d8dc-4594-8cd4-
:

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

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.


--
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.

David

In article , David says...

"Conor" wrote in message
...
In article
39, bz
says...

wrote in
news:f8d97d59-d8dc-4594-8cd4-
:

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

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.


--
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.




--
Conor

I only please one person per day. Today is not your day. Tomorrow isn't
looking good either. - Scott Adams

On Feb 19, 10:57*am, "David" wrote:
"Conor" wrote in message

...



In article
39, bz
says...

wrote in
news:f8d97d59-d8dc-4594-8cd4-
:

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

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.

--
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.

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.

On Feb 19, 7:35*am, bz wrote:
wrote in news:f8d97d59-d8dc-4594-8cd4-
:

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

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.

wrote in news:d972e65d-ba83-4734-b5b7-
:

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:Ca...d-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:Ca...ectrolytic.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.

remove ch100-5 to avoid spam trap

In sci.electronics.repair Conor wrote:
In article 39, bz
says...

wrote in news:f8d97d59-d8dc-4594-8cd4-
:

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

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.

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

Jerry

In sci.electronics.repair wrote:
On Feb 19, 10:57*am, "David" wrote:
"Conor" wrote in message

...



In article
39, bz
says...

wrote in
news:f8d97d59-d8dc-4594-8cd4-
:

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

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.

--
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.

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.

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

Jerry

In sci.electronics.repair wrote:
On Feb 18, 6:25*pm, Jerry Peters wrote:
In sci.electronics.repair wrote:
On Feb 17, 6:35*pm, "tg" wrote:
I have a Compaq laptop Model Presario, service tag C300EA that will not
start. It's this one:http://www.microdevices.lk/images/Laptop.jpg
the motherboard is an IBL30 LA-3324P and they retail for about £125.
ouch
The problem is when I plug a power supply into it and press the on/off
button the power led flashes rapidly for a few seconds and then cuts
out. I then have to wait about a minute before it will light up again.
I've tried three different power supplies, one of them coming from a
battery/voltage converter and all three power supplies produce the same
fault on the laptop so it's not the power supply. It acts the same with
or without a battery fitted. When the power supply is plugged in I did
notice the battery icon flickers all the time with no battery in.
I also connected an amp meter to the power supply and when the power
light does flicker there is virtually no current draw into the laptop.
I split the chassis to take a look and saw that the power socket wires
go straight onto the motherboard. There is no power board or
daughtercard as such..
does anyone have an idea if there's a known component that causes this
problem? or is it a case of new motherboard?
thanks for any pointers.

The symptoms suggest a short on the mainboard, the PSU aren't able to
regulate so their protection circuits are cycling them off as best
they can (at the price-point of the design).

There isn't much you can do at this point except strip the mainboard
down as much as possible. *Disconnect hard drive, optical, memory, CPU
(except if you take the heatsink off and it was heatsinking the
chipset, you must put that heatsink back on and ensure it makes good
contact with the chipset still), card reader, screen, inverter board.
See if it will then "seem" (since you have no screen, watch the power
LED(s)) to stay on. *It may not, without a processor and memory. *If
necessary put those back in and retry. *If it stays on, reconnect
screen but not the backpanel lighting inverter yet. *If it turns on
and stays on, see if there is output to the screen by shining a strong
flashlight on it.

If it works this far, an inverter failure is a common cause. *If it
didn't work at all up to this point, mainboard probably needs
replaced. *If it works up to some point in the middle, suspect the part
(s) you added at that point. *These days such a problem is typically
handled by replacing the mainboard at a repair shop, then if that
doesn't work they replace the next part and so on, till it's fixed or
the customer refuses to pay for their diagnosed problem since often
the laptop cost little more than the total repair cost.

Had a problem like that with an old Dell laptop. Measuring the
resistance across the power input jack showed a direct short. After
disassembling the unit I found an electrolytic across the power lines,
after the rf filter & fuse that was shorted. Removed it and the laptop
now works fine (so much for no electrolytics in laptops).

* * * * Jerry

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

In article vVjnl.387314$Mh5.177109@bgtnsc04-
news.ops.worldnet.att.net, lid says...
In sci.electronics.repair Conor wrote:
In article 39, bz
says...

wrote in news:f8d97d59-d8dc-4594-8cd4-
:

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

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.

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).

wrote:

On Feb 18, 6:20Â*pm, Jerry Peters wrote:
In sci.electronics.repair wrote:
On Feb 18, 1:09Â*am, jakdedert wrote:
Conor wrote:
In article , Rich
Webb says...

Perhaps the plague? No, not THAT one, THIS one:
http://en.wikipedia.org/wiki/Capacitor_plague

Worth eyeballing since you already have the main board exposed.

Didn't think laptops used electrolytic capacitors...

They're surface mount, so you might not recognize them. Â*Google is
your friend....

Yes, but, although surface mount caps can be electrolytic, in a
notebook (none at all if it's a good design), very few caps are
electrolytic, if any, except in the external brick AC-DC PSU.

That's complete nonsense, of course a laptop uses electrolytics, and
lots of them to filter power throughout the unit. As jakedart said
they're surface mount units. Take one apart sometime & look.

Jerry

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 !

The ceramics of course are tan.
There are plenty more pictures from 3rd parties available with a
google search if you can't accept the above pics are typical:
http://images.google.com/images?q=laptop+mainboard

--
Best Regards:
Baron.

wrote:

On Feb 19, 12:19Â*am, wrote:
... BTW, this is the whole thing
there is no separate power board:

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 !

--
Best Regards:
Baron.

On Feb 19, 3:24*pm, bz wrote:
wrote in news:d972e65d-ba83-4734-b5b7-
:

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:Ca...d-polarity.jpg

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

On Feb 19, 4:13*pm, Jerry Peters wrote:
In sci.electronics.repair wrote:
On Feb 19, 10:57*am, "David" wrote:
"Conor" wrote in message

...

In article
39, bz
says...

wrote in
news:f8d97d59-d8dc-4594-8cd4-
:

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

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.

--
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.

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.

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?

On Feb 19, 4:10*pm, Jerry Peters wrote:
In sci.electronics.repair Conor wrote:

In article 39, bz
says...

wrote in news:f8d97d59-d8dc-4594-8cd4-
:

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

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.

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.

On Feb 19, 4:16*pm, Jerry Peters wrote:
In sci.electronics.repair wrote:
On Feb 18, 6:25*pm, Jerry Peters wrote:
In sci.electronics.repair wrote:
On Feb 17, 6:35*pm, "tg" wrote:
I have a Compaq laptop Model Presario, service tag C300EA that will not
start. It's this one:http://www.microdevices.lk/images/Laptop.jpg
the motherboard is an IBL30 LA-3324P and they retail for about £125.
ouch
The problem is when I plug a power supply into it and press the on/off
button the power led flashes rapidly for a few seconds and then cuts
out. I then have to wait about a minute before it will light up again.
I've tried three different power supplies, one of them coming from a
battery/voltage converter and all three power supplies produce the same
fault on the laptop so it's not the power supply. It acts the same with
or without a battery fitted. When the power supply is plugged in I did
notice the battery icon flickers all the time with no battery in.
I also connected an amp meter to the power supply and when the power
light does flicker there is virtually no current draw into the laptop.
I split the chassis to take a look and saw that the power socket wires
go straight onto the motherboard. There is no power board or
daughtercard as such..
does anyone have an idea if there's a known component that causes this
problem? or is it a case of new motherboard?
thanks for any pointers.

The symptoms suggest a short on the mainboard, the PSU aren't able to
regulate so their protection circuits are cycling them off as best
they can (at the price-point of the design).

There isn't much you can do at this point except strip the mainboard
down as much as possible. *Disconnect hard drive, optical, memory, CPU
(except if you take the heatsink off and it was heatsinking the
chipset, you must put that heatsink back on and ensure it makes good
contact with the chipset still), card reader, screen, inverter board..
See if it will then "seem" (since you have no screen, watch the power
LED(s)) to stay on. *It may not, without a processor and memory. *If
necessary put those back in and retry. *If it stays on, reconnect
screen but not the backpanel lighting inverter yet. *If it turns on
and stays on, see if there is output to the screen by shining a strong
flashlight on it.

If it works this far, an inverter failure is a common cause. *If it
didn't work at all up to this point, mainboard probably needs
replaced. *If it works up to some point in the middle, suspect the part
(s) you added at that point. *These days such a problem is typically
handled by replacing the mainboard at a repair shop, then if that
doesn't work they replace the next part and so on, till it's fixed or
the customer refuses to pay for their diagnosed problem since often
the laptop cost little more than the total repair cost.

Had a problem like that with an old Dell laptop. Measuring the
resistance across the power input jack showed a direct short. After
disassembling the unit I found an electrolytic across the power lines,
after the rf filter & fuse that was shorted. Removed it and the laptop
now works fine (so much for no electrolytics in laptops).

* * * * Jerry

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

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.

On Feb 19, 3:24*pm, bz wrote:
wrote in news:d972e65d-ba83-4734-b5b7-
:

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:Ca...d-polarity.jpg

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

wrote in news:58f338af-65bf-42a4-b96e-
:

On Feb 19, 3:24*pm, bz wrote:
wrote in news:d972e65d-ba83-4734-b5b7-
:

Nope. *There are wet tantalum capacitors (that exist), but nobody use
s
.....
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'.
.....

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.

[quote]
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.

remove ch100-5 to avoid spam trap

On Feb 19, 7:16*pm, bz wrote:
wrote in news:58f338af-65bf-42a4-b96e-
:





On Feb 19, 3:24*pm, bz wrote:
wrote in news:d972e65d-ba83-4734-b5b7-
:

Nope. *There are wet tantalum capacitors (that exist), but nobody use
s
....
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'.
....

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.

[quote]
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.

* 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.

On Feb 19, 4:13*pm, Jerry Peters wrote:
In sci.electronics.repair wrote:
On Feb 19, 10:57*am, "David" wrote:
"Conor" wrote in message

...

In article
39, bz
says...

wrote in
news:f8d97d59-d8dc-4594-8cd4-
:

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

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.

--
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.

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.

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).