laptop power fault: compaq presario C300EA

T

tg

Guest
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 Ł125.
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" <tg@nospamevereverever.net>
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 Ł125.
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.
Click to expand...
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
 
In article <p5jmp4tnc8bi0ql9044d8uo4uons77mgtb@4ax.com>, 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.
Click to expand...
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, 6:35 pm, "tg" <t...@nospamevereverever.net> 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 Ł125.
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.
Click to expand...
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.
 
On Feb 17, 7:16 pm, Conor <conor_tur...@hotmail.com> wrote:
In article <p5jmp4tnc8bi0ql9044d8uo4uons77m...@4ax.com>, 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
Click to expand...
What did you think they used for capacitors in the power supply?
 
Conor wrote:
In article <p5jmp4tnc8bi0ql9044d8uo4uons77mgtb@4ax.com>, 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
Click to expand...
friend....
 
On Feb 18, 1:09 am, jakdedert <jakded...@bellsouth.net> wrote:
Conor wrote:
In article <p5jmp4tnc8bi0ql9044d8uo4uons77m...@4ax.com>, 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....
Click to expand...
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.
 
On Feb 18, 12:33 am, "hr(bob) hofm...@att.net" <hrhofm...@att.net>
wrote:
On Feb 17, 7:16 pm, Conor <conor_tur...@hotmail.com> wrote:

In article <p5jmp4tnc8bi0ql9044d8uo4uons77m...@4ax.com>, 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?
Click to expand...
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.
 
In article <23249f90-8ab6-4d4f-b2d2-4de755ce52f5
@l37g2000vba.googlegroups.com>, hr(bob) hofmann@att.net says...

What did you think they used for capacitors in the power supply?
Click to expand...
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 <ovNml.5290$9a.2073@bignews1.bellsouth.net>, jakdedert
says...
Conor wrote:
In article <p5jmp4tnc8bi0ql9044d8uo4uons77mgtb@4ax.com>, 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....
Click to expand...
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 <conor_turton@hotmail.com>
wrote:

In article <ovNml.5290$9a.2073@bignews1.bellsouth.net>, jakdedert
says...

Conor wrote:
In article <p5jmp4tnc8bi0ql9044d8uo4uons77mgtb@4ax.com>, 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.
Click to expand...
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
 
On Tue, 17 Feb 2009 23:35:37 -0000, "tg" <tg@nospamevereverever.net>
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 Ł125.
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.
Click to expand...
Check that it's not the Compaq model that used RAM for BIOS and dies
when the backup battery gets low.
 
On Tue, 17 Feb 2009 23:35:37 -0000, "tg"
<tg@nospamevereverever.net>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.
Click to expand...
Bad ram.
 
In sci.electronics.repair emailaddress@insightbb.com wrote:
On Feb 18, 1:09 am, jakdedert <jakded...@bellsouth.net> wrote:
Conor wrote:
In article <p5jmp4tnc8bi0ql9044d8uo4uons77m...@4ax.com>, 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.
Click to expand...
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 emailaddress@insightbb.com wrote:
On Feb 17, 6:35 pm, "tg" <t...@nospamevereverever.net> 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 Ł125.
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.
Click to expand...
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 <conor_turton@hotmail.com> wrote:

In article <ovNml.5290$9a.2073@bignews1.bellsouth.net>, jakdedert
says...

Conor wrote:
In article <p5jmp4tnc8bi0ql9044d8uo4uons77mgtb@4ax.com>, 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.
Click to expand...
I guess you'll never own one then ....
 
On Feb 18, 6:25 pm, Jerry Peters <je...@example.invalid> wrote:
In sci.electronics.repair emailaddr...@insightbb.com wrote:
On Feb 17, 6:35 pm, "tg" <t...@nospamevereverever.net> 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 Ł125.
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
Click to expand...
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.
 
On Feb 18, 9:06 pm, rebel <m...@privacy.net> wrote:
On Wed, 18 Feb 2009 13:54:47 -0000, Conor <conor_tur...@hotmail.com> wrote:
In article <ovNml.5290$9a.2...@bignews1.bellsouth.net>, jakdedert
says...

Conor wrote:
In article <p5jmp4tnc8bi0ql9044d8uo4uons77m...@4ax.com>, 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 ....
Click to expand...
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, 6:20 pm, Jerry Peters <je...@example.invalid> wrote:
In sci.electronics.repair emailaddr...@insightbb.com wrote:
On Feb 18, 1:09 am, jakdedert <jakded...@bellsouth.net> wrote:
Conor wrote:
In article <p5jmp4tnc8bi0ql9044d8uo4uons77m...@4ax.com>, 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
Click to expand...
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, emailaddr...@insightbb.com wrote:
... BTW, this is the whole thing
there is no separate power board:
Click to expand...
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.
 
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