Toshiba Laptop suddenly "loses" wall power

I've searched around a bit but can't find anyone else with this exact
problem.

From time to time, my Toshiba laptop (P35-S6292) spontaneously loses
the power feed coming from the wall and switches over to battery
power. The icon on the task bar changes from the little plug to the
battery, the screen dims as I have configured the power options and
the LED on the underside of the front of the machine is dark. It's as
if the power supply isn't plugged in at all.

If I shut the machine down in this state (Start -- Shut Down), the
machine _almost_ shuts down completely. Windows shuts down, the hard
drives stop spinning, the LCD turns off, the fans all shut off, but
the little blue LED surrounding the power button stays on. It stays
in this state until I remove the jack on the power supply from the
back of the machine and then it's really off.

If I then plug the power supply back into the port on the back of the
laptop, the power LED on the front underside of the laptop lights back
up again, and when I turn the laptop back on, it runs off wall power
once again.

Sometimes I don't experience it once in two weeks, and then on some
days I'm shutting down and restarting three times in a night. That's
_really_ annoying.

Anyone experienced this besides me?

I'm assuming that installing run-of-the-mill software packages will
not cause this kind of problem.

The last major platform change that was made to this machine was that
it did have its BIOS upgraded when I last brought it in for
servicing. The problem I was experiencing was screen-related. I
decided not to have the screen replaced, but the service center did
disassemble the machine, blow out the dust and upgrade my BIOS.

I suspect the BIOS upgrade and I'm trying to determine if I can get my
hands on the original BIOS to restore it.

But I'm also open to anything else I should do to rectify the problem.

Any help you can offer is appreciated, thanks!

wrote:

I've searched around a bit but can't find anyone else with this exact problem.

Then you need to do some basic fault finding.

From time to time, my Toshiba laptop (P35-S6292) spontaneously loses
the power feed coming from the wall and switches over to battery power.
The icon on the task bar changes from the little plug to the battery, the
screen dims as I have configured the power options and the LED on the
underside of the front of the machine is dark. It's as if the power supply
isn't plugged in at all.

Then the first thing to do is to decide which of two obvious possibilitys is happening.

Either the wall power is going away at times, due to a bad mains
lead, a bad power supply that plugs into the wall, or a bad connection
of that to the laptop, or all of those are fine and the laptop is deciding
that the wall power is going away when it isnt. The first is MUCH more
likely and can be checked by someone who can do basic diagnosis
by monitoring the voltage just back from the connection of the wall
power to the laptop, back inside the laptop a bit so you can see if the
problem is a faulty connector there. That can be done with a multimeter.

If you discover that the wall power is indeed going away when the
laptop decides that it is, you just have to decide if its a bad connector
on the laptop thats not making good contact all the time, that there is
a cracked solder joint where thats soldered into the laptop, or whether
the power pack is faulty, or one of the two leads, in and out of that.

If I shut the machine down in this state (Start -- Shut Down), the
machine _almost_ shuts down completely. Windows shuts down,
the hard drives stop spinning, the LCD turns off, the fans all shut
off, but the little blue LED surrounding the power button stays on.
It stays in this state until I remove the jack on the power supply
from the back of the machine and then it's really off.

Does that only happen when the laptop has decided that its not on wall power anymore ?

If I then plug the power supply back into the port on the back of the
laptop, the power LED on the front underside of the laptop lights back up
again, and when I turn the laptop back on, it runs off wall power once again.

That suggests its a flakey connection somewhere, most likely the connector
where the power pack plugs into the laptop. They do fail there quite often.

Sometimes I don't experience it once in two weeks, and then on
some days I'm shutting down and restarting three times in a night.

What happens if you wriggle the connector for
the wall power where it goes into the laptop ?

That's _really_ annoying.

Anyone experienced this besides me?

Yep, its quite a common failure mode for a laptop.

I'm assuming that installing run-of-the-mill software
packages will not cause this kind of problem.

Very unlikely to be that.

The last major platform change that was made to this machine was
that it did have its BIOS upgraded when I last brought it in for servicing.
The problem I was experiencing was screen-related. I decided not to
have the screen replaced, but the service center did disassemble the
machine, blow out the dust and upgrade my BIOS.

I suspect the BIOS upgrade

Thats unlikely given its a Toshiba.

and I'm trying to determine if I can get my hands on the original BIOS to restore it.

But I'm also open to anything else I should do to rectify the problem.

Try wriggling the plug where the wall power plugs into the
laptop and see if you can get it to decide its lost wall power.

Any help you can offer is appreciated, thanks!

On 11 Mar 2007 16:30:24 -0700,
wrote:

I've searched around a bit but can't find anyone else with this exact
problem.

From time to time, my Toshiba laptop (P35-S6292) spontaneously loses
the power feed coming from the wall and switches over to battery
power. The icon on the task bar changes from the little plug to the
battery, the screen dims as I have configured the power options and
the LED on the underside of the front of the machine is dark. It's as
if the power supply isn't plugged in at all.

If I shut the machine down in this state (Start -- Shut Down), the
machine _almost_ shuts down completely. Windows shuts down, the hard
drives stop spinning, the LCD turns off, the fans all shut off, but
the little blue LED surrounding the power button stays on. It stays
in this state until I remove the jack on the power supply from the
back of the machine and then it's really off.

If I then plug the power supply back into the port on the back of the
laptop, the power LED on the front underside of the laptop lights back
up again, and when I turn the laptop back on, it runs off wall power
once again.

Sometimes I don't experience it once in two weeks, and then on some
days I'm shutting down and restarting three times in a night. That's
_really_ annoying.

Anyone experienced this besides me?

It could be the power supply itself- you could rig up some
kind of multimeter to monitor it, but more often it's that
the power jack on the laptop has come loose due to being a
poor mechanical design.

Unfortunately it's going to require replacing the whole
mainboard which is quite expensive unless laptop is under
warranty, unless you can find a repairshop to do it (which
is quite possible), or do it yourself. If you are included
to DIY, that would be the preferred path to take for cost
effectiveness, if you have the spare time.



I'm assuming that installing run-of-the-mill software packages will
not cause this kind of problem.

No they shouldn't.


The last major platform change that was made to this machine was that
it did have its BIOS upgraded when I last brought it in for
servicing. The problem I was experiencing was screen-related. I
decided not to have the screen replaced, but the service center did
disassemble the machine, blow out the dust and upgrade my BIOS.

I suspect the BIOS upgrade and I'm trying to determine if I can get my
hands on the original BIOS to restore it.

But I'm also open to anything else I should do to rectify the problem.

Any help you can offer is appreciated, thanks!

You might (very gently) wiggle the power plug while plugged
in to see if that causes or resolves it. A bad power plug
or plug pulling loose from the circuit board is a pretty
common failure on laptops.

On Mar 11, 11:53 pm, kony wrote:
On 11 Mar 2007 16:30:24 -0700,
wrote:



I've searched around a bit but can't find anyone else with this exact
problem.

From time to time, my Toshiba laptop (P35-S6292) spontaneously loses
the power feed coming from the wall and switches over to battery
power. The icon on the task bar changes from the little plug to the
battery, the screen dims as I have configured the power options and
the LED on the underside of the front of the machine is dark. It's as
if the power supply isn't plugged in at all.

If I shut the machine down in this state (Start -- Shut Down), the
machine _almost_ shuts down completely. Windows shuts down, the hard
drives stop spinning, the LCD turns off, the fans all shut off, but
the little blue LED surrounding the power button stays on. It stays
in this state until I remove the jack on the power supply from the
back of the machine and then it's really off.

If I then plug the power supply back into the port on the back of the
laptop, the power LED on the front underside of the laptop lights back
up again, and when I turn the laptop back on, it runs off wall power
once again.

Sometimes I don't experience it once in two weeks, and then on some
days I'm shutting down and restarting three times in a night. That's
_really_ annoying.

Anyone experienced this besides me?

It could be the power supply itself- you could rig up some
kind of multimeter to monitor it, but more often it's that
the power jack on the laptop has come loose due to being a
poor mechanical design.

Unfortunately it's going to require replacing the whole
mainboard which is quite expensive unless laptop is under
warranty, unless you can find a repairshop to do it (which
is quite possible), or do it yourself. If you are included
to DIY, that would be the preferred path to take for cost
effectiveness, if you have the spare time.



I'm assuming that installing run-of-the-mill software packages will
not cause this kind of problem.

No they shouldn't.



The last major platform change that was made to this machine was that
it did have its BIOS upgraded when I last brought it in for
servicing. The problem I was experiencing was screen-related. I
decided not to have the screen replaced, but the service center did
disassemble the machine, blow out the dust and upgrade my BIOS.

I suspect the BIOS upgrade and I'm trying to determine if I can get my
hands on the original BIOS to restore it.

But I'm also open to anything else I should do to rectify the problem.

Any help you can offer is appreciated, thanks!

You might (very gently) wiggle the power plug while plugged
in to see if that causes or resolves it. A bad power plug
or plug pulling loose from the circuit board is a pretty
common failure on laptops.

These are all excellent suggestions.

Instead of detailing this in my original note (trying not to make my
original note too long), I have already performed some
troubleshooting:

(1) Used a multimeter to determine that the power coming from the
power supply is within spec
(2) Wiggled the following connection points of the power supply while
connected to the multimeter: jack end, cord connection at the
transformer, plug connection at the wall.
(3) Wiggled the power jack while it was connected to the machine

At no time was I able to get the power reading on the Multimeter to
drop to zero nor was I able to make the laptop switch over to battery
power "on demand". In addition, once the laptop had decided the wall
power had disappeared, no amount of cord-wiggling, removal or
reinsertion was able to get the laptop to kick back over to the wall
power supply.

If I were dealing with a short or a faulty connection anywhere along
the line I would expect that, once the laptop had switched itself over
to battery power, I would be able to get the laptop to switch back to
wall power, even if only momentarily, by wiggling the wires and/or
jack connections. A faulty connection should work both ways - it
should fail and succeed by wiggling of the wires - but I have not once
observed this to happen.

Once it's on battery power it's running off batteries until its shut
down, no matter what else I do.

I recently blew the dust back out of my machine once again - perhaps
something metallic had found its way onto the power traces - but I'm
still leaning towards a BIOS issue with the version of the BIOS my
machine is running now.

Thanks for all your thoughts.

Instead of detailing this in my original note (trying not to make my
original note too long), I have already performed some
troubleshooting:

(1) Used a multimeter to determine that the power coming from the
power supply is within spec
(2) Wiggled the following connection points of the power supply while
connected to the multimeter: jack end, cord connection at the
transformer, plug connection at the wall.
(3) Wiggled the power jack while it was connected to the machine

At no time was I able to get the power reading on the Multimeter to
drop to zero nor was I able to make the laptop switch over to battery
power "on demand". In addition, once the laptop had decided the wall
power had disappeared, no amount of cord-wiggling, removal or
reinsertion was able to get the laptop to kick back over to the wall
power supply.

If I were dealing with a short or a faulty connection anywhere along
the line I would expect that, once the laptop had switched itself over
to battery power, I would be able to get the laptop to switch back to
wall power, even if only momentarily, by wiggling the wires and/or
jack connections. A faulty connection should work both ways - it
should fail and succeed by wiggling of the wires - but I have not once
observed this to happen.

Once it's on battery power it's running off batteries until its shut
down, no matter what else I do.

I recently blew the dust back out of my machine once again - perhaps
something metallic had found its way onto the power traces - but I'm
still leaning towards a BIOS issue with the version of the BIOS my
machine is running now.

Thanks for all your thoughts.- Hide quoted text -

- Show quoted text -

Have you explored the possibility that the PSU or Laptop are going
into a protection mode? Many PSUs will shut down if they are becoming
hot or detect a fault (which can be caused by a bad lead) and wont
come back until the psu is allowed to stand for some time (few
minutes).

It may be that something else is hapenning that the Laptop doesnt like
and is killing the connection, one I have seen is excessive ripple
caused by power supply caps drying out/bursting causing spontaneous
shoutdown in Lexbook systems and IBM POS Beetles.


P

On 12 Mar 2007 04:04:15 -0700,
wrote:


Instead of detailing this in my original note (trying not to make my
original note too long), I have already performed some
troubleshooting:

(1) Used a multimeter to determine that the power coming from the
power supply is within spec
(2) Wiggled the following connection points of the power supply while
connected to the multimeter: jack end, cord connection at the
transformer, plug connection at the wall.
(3) Wiggled the power jack while it was connected to the machine

At no time was I able to get the power reading on the Multimeter to
drop to zero nor was I able to make the laptop switch over to battery
power "on demand". In addition, once the laptop had decided the wall
power had disappeared, no amount of cord-wiggling, removal or
reinsertion was able to get the laptop to kick back over to the wall
power supply.

If I were dealing with a short or a faulty connection anywhere along
the line I would expect that, once the laptop had switched itself over
to battery power, I would be able to get the laptop to switch back to
wall power, even if only momentarily, by wiggling the wires and/or
jack connections. A faulty connection should work both ways - it
should fail and succeed by wiggling of the wires - but I have not once
observed this to happen.

While it might still be possible to have an intermittent
connection with the jack/traces that varies per temperature,
I would begin to suspect the mainboard has cold joints or
cracks. You can look it over with a strong light,
magnifying glass, and try to run it like that if possible
but it might be hard to find from inspection, so you'd use a
meter to trace back the circuit from the PSU jack as far as
possible.