This is my wife's laptop which I posted recently. It had somehow
mysteriously "acquired" an unknown CMOS password which was preventing
me from getting through post and into boot. I believe that it was Jeff
who found a thread on another group which talked about this very thing
and offered a procedure for resolving it. I performed the procedure
and it cleared the password, (or whatever it was that was blocking the
boot sequence). I was very grateful for that help. After doing this
though the computer seemed flaky, freezing at times,etc, So we dumped
the hard drive and reloaded Windows. Now it seems to work fairly well
on battery, however most times, (but not always) oddly plugging the
power supply in will cause the computer to freeze. It is then
necessary to do a hard power down and boot back up with just battery.
This has always seemed to work. Most times though if the power cord is
connected it will either not boot, or it will boot, let you do a
couple of things like maybe get to a Website, and then perhaps a
couple of more keystrokes and then it will freeze. I have repeated
this problem many times now since clearing the phantom password and it
seems to be consistently tied into operating on AC power. Does anyone
have any ideas about this? Thanks, Lenny

I'm reminded of the joke about the patient raising an arm above his head and
saying "It hurts when I do that, doctor!"

"Well, don't do that!"

Obviously you can't run the computer solely on battery power.

Can you get ahold of a new power supply? It's possible the supply you have is
noisy, or generates a transient when plugged into the computer.

On Thu, 3 Jan 2013 21:28:50 -0800 (PST), klem kedidelhopper
wrote:

This is my wife's laptop which I posted recently. It had somehow
mysteriously "acquired" an unknown CMOS password which was preventing
me from getting through post and into boot. I believe that it was Jeff
who found a thread on another group which talked about this very thing
and offered a procedure for resolving it. I performed the procedure
and it cleared the password, (or whatever it was that was blocking the
boot sequence). I was very grateful for that help. After doing this
though the computer seemed flaky, freezing at times,etc, So we dumped
the hard drive and reloaded Windows. Now it seems to work fairly well
on battery, however most times, (but not always) oddly plugging the
power supply in will cause the computer to freeze. It is then
necessary to do a hard power down and boot back up with just battery.
This has always seemed to work. Most times though if the power cord is
connected it will either not boot, or it will boot, let you do a
couple of things like maybe get to a Website, and then perhaps a
couple of more keystrokes and then it will freeze. I have repeated
this problem many times now since clearing the phantom password and it
seems to be consistently tied into operating on AC power. Does anyone
have any ideas about this? Thanks, Lenny


Have you cleaned out the cpu heatsink fins or is the cpu fan not
working? The cpu runs faster when plugged into power and might be
overheating. Chuck

On Jan 4, 9:56*am, chuck wrote:
On Thu, 3 Jan 2013 21:28:50 -0800 (PST), klem kedidelhopper









wrote:
This is my wife's laptop which I posted recently. It had somehow
mysteriously "acquired" an unknown *CMOS password which was preventing
me from getting through post and into boot. I believe that it was Jeff
who found a thread on another group which talked about this very thing
and offered a procedure for resolving it. I performed the procedure
and it cleared the password, (or whatever it was that was blocking the
boot sequence). I was very grateful for that help. After doing this
though the computer seemed flaky, freezing at times,etc, So we dumped
the hard drive and reloaded Windows. Now it seems to work fairly well
on battery, however most times, (but not always) oddly plugging the
power supply in will cause the computer to freeze. It is then
necessary to *do a hard power down and boot back up with just battery.
This has always seemed to work. Most times though if the power cord is
connected it will either not boot, or it will boot, let you do a
couple of things like maybe get to a Website, and then perhaps a
couple of more keystrokes and then it will freeze. I have repeated
this problem many times now since clearing the phantom password and it
seems to be consistently tied into operating on AC power. Does anyone
have any ideas about this? Thanks, Lenny

Have you cleaned out the cpu heatsink fins or is the cpu fan not
working? *The cpu runs faster when plugged into power and might be
overheating. *Chuck
When I had it apart to reset the Eprom the fan and heat sink looked
pretty clean. I think I'll look at the power supply output on the
scope and while observing it I'll load it and see if anything happens.
If you guys have any more ideas though, I'm all ears. Lenny.

On Thu, 3 Jan 2013 21:28:50 -0800 (PST), klem kedidelhopper
wrote:

This is my wife's laptop which I posted recently. It had somehow
mysteriously "acquired" an unknown CMOS password which was preventing
me from getting through post and into boot. I believe that it was Jeff
who found a thread on another group which talked about this very thing
and offered a procedure for resolving it. I performed the procedure
and it cleared the password, (or whatever it was that was blocking the
boot sequence). I was very grateful for that help. After doing this
though the computer seemed flaky, freezing at times,etc, So we dumped
the hard drive and reloaded Windows. Now it seems to work fairly well
on battery, however most times, (but not always) oddly plugging the
power supply in will cause the computer to freeze. It is then
necessary to do a hard power down and boot back up with just battery.
This has always seemed to work. Most times though if the power cord is
connected it will either not boot, or it will boot, let you do a
couple of things like maybe get to a Website, and then perhaps a
couple of more keystrokes and then it will freeze. I have repeated
this problem many times now since clearing the phantom password and it
seems to be consistently tied into operating on AC power. Does anyone
have any ideas about this? Thanks, Lenny
My wife's Dell laptop was acting flaky when run on AC. LEDs flashing
randomly and refusal to boot up. Sometimes it would boot up and then
lock up. I traced it to the power supply. There are three wires in the
power supply cable. Of the three two are of a heavier gauge than the
third. One of the heavier wires, the braided one that also acts as a
shield was soldered badly. All I did was reflow the solder to this
wire and the laptop resumed normal operation.
Eric

On 1/4/2013 5:56 PM, klem kedidelhopper wrote:
On Jan 4, 9:56 am, chuck wrote:
On Thu, 3 Jan 2013 21:28:50 -0800 (PST), klem kedidelhopper









wrote:
This is my wife's laptop which I posted recently. It had somehow
mysteriously "acquired" an unknown CMOS password which was preventing
me from getting through post and into boot. I believe that it was Jeff
who found a thread on another group which talked about this very thing
and offered a procedure for resolving it. I performed the procedure
and it cleared the password, (or whatever it was that was blocking the
boot sequence). I was very grateful for that help. After doing this
though the computer seemed flaky, freezing at times,etc, So we dumped
the hard drive and reloaded Windows. Now it seems to work fairly well
on battery, however most times, (but not always) oddly plugging the
power supply in will cause the computer to freeze. It is then
necessary to do a hard power down and boot back up with just battery.
This has always seemed to work. Most times though if the power cord is
connected it will either not boot, or it will boot, let you do a
couple of things like maybe get to a Website, and then perhaps a
couple of more keystrokes and then it will freeze. I have repeated
this problem many times now since clearing the phantom password and it
seems to be consistently tied into operating on AC power. Does anyone
have any ideas about this? Thanks, Lenny

Have you cleaned out the cpu heatsink fins or is the cpu fan not
working? The cpu runs faster when plugged into power and might be
overheating. Chuck
When I had it apart to reset the Eprom the fan and heat sink looked
pretty clean. I think I'll look at the power supply output on the
scope and while observing it I'll load it and see if anything happens.
If you guys have any more ideas though, I'm all ears. Lenny.

Did you replace the backup battery?

On Jan 4, 5:08*pm, tuinkabouter wrote:
On 1/4/2013 5:56 PM, klem kedidelhopper wrote:









On Jan 4, 9:56 am, chuck wrote:
On Thu, 3 Jan 2013 21:28:50 -0800 (PST), klem kedidelhopper

wrote:
This is my wife's laptop which I posted recently. It had somehow
mysteriously "acquired" an unknown *CMOS password which was preventing
me from getting through post and into boot. I believe that it was Jeff
who found a thread on another group which talked about this very thing
and offered a procedure for resolving it. I performed the procedure
and it cleared the password, (or whatever it was that was blocking the
boot sequence). I was very grateful for that help. After doing this
though the computer seemed flaky, freezing at times,etc, So we dumped
the hard drive and reloaded Windows. Now it seems to work fairly well
on battery, however most times, (but not always) oddly plugging the
power supply in will cause the computer to freeze. It is then
necessary to *do a hard power down and boot back up with just battery.
This has always seemed to work. Most times though if the power cord is
connected it will either not boot, or it will boot, let you do a
couple of things like maybe get to a Website, and then perhaps a
couple of more keystrokes and then it will freeze. I have repeated
this problem many times now since clearing the phantom password and it
seems to be consistently tied into operating on AC power. Does anyone
have any ideas about this? Thanks, Lenny

Have you cleaned out the cpu heatsink fins or is the cpu fan not
working? *The cpu runs faster when plugged into power and might be
overheating. *Chuck
When I had it apart to reset the Eprom the fan and heat sink looked
pretty clean. I think I'll look at the power supply output on the
scope and while observing it I'll load it and see if anything happens.
If you guys have any more ideas though, I'm all ears. Lenny.

Did you replace the backup battery?

I didn't because the time and date and all parameters seemed to have
stayed up. Lenny

It may be screwed up. For now, to deal with it set the power balance the same for AC and battery and see what happens.

Almost all laptops dim the display and change the processor mode from performance on AC to economy on battery. This is the main thing that could be freezing the OS. If it was rebooting, shutting down or something then that would be different. It is looking for a power configuration that is likely not there.

On mine I can control it from Windows, but not all machines will have that and if you reload or reset stuff, this config data coulld be missing or corrupt. It can be in BIOS or the OS, or both. (kinda like control panel)

Go back into setup, find power management. If you can find in there ANYWHERE that differentiates between battery power and AC, set them identical. Or turn the whole feature clean off if possible.

Incidentally, before proceeding, will it boot up from AC power ? If so, does DISconnecting the AC power cause this as well ? If not, you set everything to run as if it on batteries all the time. In fact that is probably best anyway, unless it dims the screen and makes it hard to see. I only run mine on battery in the dark because otherwise it is too hard to see.

Hell, I guess a solar battery for it would just about fix me up woulntit.

On Jan 4, 8:58*pm, wrote:
It may be screwed up. For now, to deal with it set the power balance the same for AC and battery and see what happens.

Almost all laptops dim the display and change the processor mode from performance on AC to economy on battery. This is the main thing that could be freezing the OS. If it was rebooting, shutting down or something then that would be different. It is looking for a power configuration that is likely not there.

On mine I can control it from Windows, but not all machines will have that and if you reload or reset stuff, this config data coulld be missing or corrupt. It can be in BIOS or the OS, or both. (kinda like control panel)

Go back into setup, find power management. If you can find in there ANYWHERE that differentiates between battery power and AC, set them identical. Or turn the whole feature clean off if possible.

Incidentally, before proceeding, will it boot up from AC power ? If so, does DISconnecting the AC power cause this as well ? If not, you set everything to run as if it on batteries all the time. In fact that is probably best anyway, unless it dims the screen and makes it hard to see. I only run mine on battery in the dark because otherwise it is too hard to see.

Hell, I guess a solar battery for it would just about fix me up woulntit.

I looked in Bios and can't find anything to do with power management
or battery power etc. I don't think it's an option on this version.
Could it be called something else? Lenny

On Jan 5, 10:27*pm, klem kedidelhopper
wrote:
On Jan 4, 8:58*pm, wrote:

It may be screwed up. For now, to deal with it set the power balance the same for AC and battery and see what happens.

Almost all laptops dim the display and change the processor mode from performance on AC to economy on battery. This is the main thing that could be freezing the OS. If it was rebooting, shutting down or something then that would be different. It is looking for a power configuration that is likely not there.

On mine I can control it from Windows, but not all machines will have that and if you reload or reset stuff, this config data coulld be missing or corrupt. It can be in BIOS or the OS, or both. (kinda like control panel)

Go back into setup, find power management. If you can find in there ANYWHERE that differentiates between battery power and AC, set them identical. Or turn the whole feature clean off if possible.

Incidentally, before proceeding, will it boot up from AC power ? If so, does DISconnecting the AC power cause this as well ? If not, you set everything to run as if it on batteries all the time. In fact that is probably best anyway, unless it dims the screen and makes it hard to see. I only run mine on battery in the dark because otherwise it is too hard to see.

Hell, I guess a solar battery for it would just about fix me up woulntit.

"BTW this never happens when you disconnect the battery. Only if you
connect it while you're using it. Lenny "

AHA ! There are regulators all over the place and most depend on electrolytic capacitors.

See where I am going with this ?

I looked in Bios and can't find anything to do with power management
or battery power etc. I don't think it's an option on this version.

The controls for power management are usually available from the operating
system. Which OS does this computer run?

On 1/6/2013 5:14 AM, William Sommerwerck wrote:
I looked in Bios and can't find anything to do with power management
or battery power etc. I don't think it's an option on this version.

The controls for power management are usually available from the
operating system. Which OS does this computer run?

Don't know if this will help, but it's made it possible for me to change
power settings in control panel on some laptops.

http://www.itexperience.net/2008/03/...power-schemes/

On Thu, 3 Jan 2013 21:28:50 -0800 (PST), klem kedidelhopper
wrote:

So we dumped
the hard drive and reloaded Windows.

What version of Windoze does this Toshiblah run? (Basic, Home, Pro,
etc)? Looking at the specs, it appears to have come with Vista.

What did you use to reload Windoze? A recovery partition on the hard
disk? A Toshiba recovery disk set? A recovery disk set that you
created? A retail Windoze CD? A random Windoze CD? It should be
something from Toshiba or you're guaranteed to have driver problems.

Oddly, I've had difficulties using the recovery partition on other
vendors (HP and Compaq) drives. It installs correctly, but then
Microsoft update refuses to update for various reasons. There are
plenty of workaround but even after they're applied, the system
usually ends up "unstable" or strange. I've had much better luck
using the manufacturers recovery CD/DVD sets.

Now it seems to work fairly well
on battery, however most times, (but not always) oddly plugging the
power supply in will cause the computer to freeze.

Toshiba uses a two wire power jack scheme, so there's no normally
closed connection in the jack. That used to cause such problems on
older laptops, but not this one.

When you say plugging in the power supply, does that mean:
1. 117VAC power is applied to the charger, and then plugged into the
laptop?
2. Or, power jack is plugged into the laptop and 117VAC is applied?
If the latter, I've seen power supplies that belch strange and
disgusting waveforms and DC when starting up and that can confuse the
laptop power management circuitry. If you have another Toshiba or 19V
clone battery charger, try it.

It is then
necessary to do a hard power down and boot back up with just battery.

So, it won't restart if the charger is plugged in? I would normally
suggest that you try running the laptop with just the charger, and
with the battery removed. However, that's risky with a possibly
defective charger, so don't try it. Replacement chargers are $8 and
up on eBay, so it may pay to just order one and see what happens.
http://www.ebay.com/sch/i.html?_trksid=p5197.m570.l1313&_nkw=toshiba+a200+ charger&_sacat=0&_from=R40

This has always seemed to work. Most times though if the power cord is
connected it will either not boot, or it will boot, let you do a
couple of things like maybe get to a Website, and then perhaps a
couple of more keystrokes and then it will freeze.

Hmmm... This sounds more like software than hardware. Google for
power management registry repair or try Microsoft Fix-It:
http://support.microsoft.com/fixit/
http://support.microsoft.com/mats/windows_battery_power_settings/

I have repeated
this problem many times now since clearing the phantom password and it
seems to be consistently tied into operating on AC power. Does anyone
have any ideas about this? Thanks, Lenny

Coincidence is a bad substitute for cause and effect. Clearing the
password probably has little to do with the power problem UNLESS you
did the procedure that requires shorting two pins on the motherboard.
One mistake, and poof.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 1/6/2013 8:49 AM, Jeff Liebermann wrote:
On Thu, 3 Jan 2013 21:28:50 -0800 (PST), klem kedidelhopper
wrote:

So we dumped
the hard drive and reloaded Windows.

What version of Windoze does this Toshiblah run? (Basic, Home, Pro,
etc)? Looking at the specs, it appears to have come with Vista.

What did you use to reload Windoze? A recovery partition on the hard
disk? A Toshiba recovery disk set? A recovery disk set that you
created? A retail Windoze CD? A random Windoze CD? It should be
something from Toshiba or you're guaranteed to have driver problems.

Oddly, I've had difficulties using the recovery partition on other
vendors (HP and Compaq) drives. It installs correctly, but then
Microsoft update refuses to update for various reasons. There are
plenty of workaround but even after they're applied, the system
usually ends up "unstable" or strange. I've had much better luck
using the manufacturers recovery CD/DVD sets.

Now it seems to work fairly well
on battery, however most times, (but not always) oddly plugging the
power supply in will cause the computer to freeze.

Toshiba uses a two wire power jack scheme, so there's no normally
closed connection in the jack. That used to cause such problems on
older laptops, but not this one.

When you say plugging in the power supply, does that mean:
1. 117VAC power is applied to the charger, and then plugged into the
laptop?
2. Or, power jack is plugged into the laptop and 117VAC is applied?
If the latter, I've seen power supplies that belch strange and
disgusting waveforms and DC when starting up and that can confuse the
laptop power management circuitry. If you have another Toshiba or 19V
clone battery charger, try it.

It is then
necessary to do a hard power down and boot back up with just battery.

So, it won't restart if the charger is plugged in? I would normally
suggest that you try running the laptop with just the charger, and
with the battery removed. However, that's risky with a possibly
defective charger, so don't try it. Replacement chargers are $8 and
up on eBay, so it may pay to just order one and see what happens.
http://www.ebay.com/sch/i.html?_trksid=p5197.m570.l1313&_nkw=toshiba+a200+ charger&_sacat=0&_from=R40

This has always seemed to work. Most times though if the power cord is
connected it will either not boot, or it will boot, let you do a
couple of things like maybe get to a Website, and then perhaps a
couple of more keystrokes and then it will freeze.

Hmmm... This sounds more like software than hardware. Google for
power management registry repair or try Microsoft Fix-It:
http://support.microsoft.com/fixit/
http://support.microsoft.com/mats/windows_battery_power_settings/

I have repeated
this problem many times now since clearing the phantom password and it
seems to be consistently tied into operating on AC power. Does anyone
have any ideas about this? Thanks, Lenny

Coincidence is a bad substitute for cause and effect. Clearing the
password probably has little to do with the power problem UNLESS you
did the procedure that requires shorting two pins on the motherboard.
One mistake, and poof.



This doesn't sound exactly like the problem, but it's a similar issue.
I have a Dell with a (formerly) bad battery...long story...the laptop
charge light blinks an error sequence.
The laptop encourages me to replace the battery by this behavior.
The battery will only charge with the computer off.
The computer always runs off battery, even when plugged in.
The only way to run on AC is to REMOVE the battery.
Battery issues can have non-obvious symptoms.

On Jan 6, 12:04*pm, mike wrote:
On 1/6/2013 8:49 AM, Jeff Liebermann wrote:







On Thu, 3 Jan 2013 21:28:50 -0800 (PST), klem kedidelhopper
*wrote:

So we dumped
the hard drive and reloaded Windows.

What version of Windoze does this Toshiblah run? *(Basic, Home, Pro,
etc)? *Looking at the specs, it appears to have come with Vista.

What did you use to reload Windoze? *A recovery partition on the hard
disk? *A Toshiba recovery disk set? *A recovery disk set that you
created? *A retail Windoze CD? *A random Windoze CD? *It should be
something from Toshiba or you're guaranteed to have driver problems.

Oddly, I've had difficulties using the recovery partition on other
vendors (HP and Compaq) drives. *It installs correctly, but then
Microsoft update refuses to update for various reasons. *There are
plenty of workaround but even after they're applied, the system
usually ends up "unstable" or strange. *I've had much better luck
using the manufacturers recovery CD/DVD sets.

Now it seems to work fairly well
on battery, however most times, (but not always) oddly plugging the
power supply in will cause the computer to freeze.

Toshiba uses a two wire power jack scheme, so there's no normally
closed connection in the jack. *That used to cause such problems on
older laptops, but not this one.

When you say plugging in the power supply, does that mean:
1. *117VAC power is applied to the charger, and then plugged into the
laptop?
2. *Or, power jack is plugged into the laptop and 117VAC is applied?
If the latter, I've seen power supplies that belch strange and
disgusting waveforms and DC when starting up and that can confuse the
laptop power management circuitry. *If you have another Toshiba or 19V
clone battery charger, try it.

It is then
necessary to *do a hard power down and boot back up with just battery.

So, it won't restart if the charger is plugged in? *I would normally
suggest that you try running the laptop with just the charger, and
with the battery removed. *However, that's risky with a possibly
defective charger, so don't try it. *Replacement chargers are $8 and
up on eBay, so it may pay to just order one and see what happens.
http://www.ebay.com/sch/i.html?_trksid=p5197.m570.l1313&_nkw=toshiba+...

This has always seemed to work. Most times though if the power cord is
connected it will either not boot, or it will boot, let you do a
couple of things like maybe get to a Website, and then perhaps a
couple of more keystrokes and then it will freeze.

Hmmm... This sounds more like software than hardware. *Google for
power management registry repair or try Microsoft Fix-It:
http://support.microsoft.com/fixit/
http://support.microsoft.com/mats/windows_battery_power_settings/

I have repeated
this problem many times now since clearing the phantom password and it
seems to be consistently tied into operating on AC power. Does anyone
have any ideas about this? Thanks, Lenny

Coincidence is a bad substitute for cause and effect. *Clearing the
password probably has little to do with the power problem UNLESS you
did the procedure that requires shorting two pins on the motherboard.
One mistake, and poof.

This doesn't sound exactly like the problem, but it's a similar issue.
I have a Dell with a (formerly) bad battery...long story...the laptop
charge light blinks an error sequence.
The laptop encourages me to replace the battery by this behavior.
The battery will only charge with the computer off.
The computer always runs off battery, even when plugged in.
The only way to run on AC is to REMOVE the battery.
Battery issues can have non-obvious symptoms.

A few observations and history:
Yes I did have to clear the bogus CMOS password problem by shorting
the two points on the mother board going by the procedure that you had
sent me the link to Jeff. And I never had this "freezing" problem
before the password issue. However it's more complicated than that.

Also I did find the power balance information that Jurb suggested. It
wasn't in BIOS but in control panel. There were three fields, and I
made them all identical but that didn't seem to make a difference.
They addressed dimming the panel on battery and two other things.

Further, after clearing the password a few weeks ago, the computer
seemed unstable. So we copied a few needed files to a memory stick
and my son dumped the hard drive and installed Windows 7 from a disc
he had, that among others had an OS version on it for "Toshiba". This
computer was given to us so we never had a rescue disk of any kind to
go with it, and unfortunately I don't recall what OS was in there
before he dumped it. So I don't know when this "freezing" problem
actually occurred, after clearing CMOS, or after he installed the new
operating system. I also don't know anything about the disc he used,
like where it came from or even if it was OEM etc.

Another observation: I always plug the AC in first. Then I connect the
19VDCjack to the computer. If I disconnect the the DC plug it's done
with the power supply still connected to 120V as well. The computer
will never freeze when disconnecting the DC plug, rather it's only
when connecting it to the computer when it's running on battery
alone.

This afternoon I looked at the power supply on the scope. This supply
is rated 19VDC 3.95A. With no load the output read 19.2V. There was a
small 20mv.low frequency triangle waveform present. Approximately
every 6 usec. there was a 160mv. spike. I took a better look at the
spikes. They actually looked like ringing pulses with a width of about
80 usec. I then loaded the supply with a 4 amp resistive load. The
voltage dropped to 18.9V and the spikes increased in amplitude to
about .900V. every 6usec.

Now given a SMPS that's charging LI-ion batteries I don't know whether
or not the above constitutes a "noisy" supply or if these kind of
aberrations are to be expected. So I figured I'd substitute my bench
supply with linear regulation as a test.

I set up 19 V with a current limit of 4A. I then connected this to the
computer and after hitting power on I immediately noticed the current
meter surging to 100ma. every second or so. The computer booted up
and worked for about 2 minutes and then just shut down. Afterwards I
was not able to get it to come back on with the bench supply. Thinking
that trying to use a linear supply to power a device with LI-ion
batteries probably wasn't the smartest thing to do I then connected
the suspect Toshiba supply and the computer booted up and never froze
during a 1 hour period of using it.
I'm chasing a ghost.

So now what I do know is that the power supply does spike up to .900V
when its fully loaded. I don't know what the actual load of the
computer is, and since I couldn't simulate this I figured I'd go for
worst case. However I think that I can assume that it must also spike
somewhat when connected to an already powered on computer as well.
Whether or not it's supposed to do this or if this is my problem is
anyone's guess. It's pretty clear that the computer does not like to
run on pure DC though. Lenny

On 1/6/2013 5:00 PM, klem kedidelhopper wrote:


Further, after clearing the password a few weeks ago, the computer
seemed unstable. So we copied a few needed files to a memory stick
and my son dumped the hard drive and installed Windows 7 from a disc
he had, that among others had an OS version on it for "Toshiba".

Not clear what that means. I've seen universal install disks for XP.
They address the OEM activation issues, but probably don't have all the
drivers you need for every version of every Toshiba computer ever made.

This afternoon I looked at the power supply on the scope. This supply
is rated 19VDC 3.95A. With no load the output read 19.2V. There was a
small 20mv.low frequency triangle waveform present. Approximately
every 6 usec. there was a 160mv. spike. I took a better look at the
spikes. They actually looked like ringing pulses with a width of about
80 usec. I then loaded the supply with a 4 amp resistive load. The
voltage dropped to 18.9V and the spikes increased in amplitude to
about .900V. every 6usec.

Assuming you have a quality scope and probes and know what you're doing,
0.9V sounds like a lot, but probably not killer.

Now given a SMPS that's charging LI-ion batteries I don't know whether
or not the above constitutes a "noisy" supply or if these kind of
aberrations are to be expected. So I figured I'd substitute my bench
supply with linear regulation as a test.

I set up 19 V with a current limit of 4A. I then connected this to the
computer and after hitting power on I immediately noticed the current
meter surging to 100ma. every second or so. The computer booted up
and worked for about 2 minutes and then just shut down. Afterwards I
was not able to get it to come back on with the bench supply. Thinking
that trying to use a linear supply to power a device with LI-ion
batteries probably wasn't the smartest thing to do I then connected
the suspect Toshiba supply and the computer booted up and never froze
during a 1 hour period of using it.
I'm chasing a ghost.

So now what I do know is that the power supply does spike up to .900V
when its fully loaded. I don't know what the actual load of the
computer is, and since I couldn't simulate this I figured I'd go for
worst case. However I think that I can assume that it must also spike
somewhat when connected to an already powered on computer as well.
Whether or not it's supposed to do this or if this is my problem is
anyone's guess. It's pretty clear that the computer does not like to
run on pure DC though. Lenny

I've seen some wacky designs, but never seen a laptop that wouldn't
run off a DC bench supply.

mike wrote:

I've seen some wacky designs, but never seen a laptop that wouldn't
run off a DC bench supply.


Some power supplies are identified by a '1 Wire' device that tells
the laptop that it's the right supply. There are three contacts at the
output plug.