fixing power supply problems in dell Inspiron 1100

My laptop(Dell Inspiron 1100) is 5 years old. Suddenly, its power
supply seems to have died. It will not start(neither the CPU,hard
drive or monitor LED's power up when I press the power on button)with
the AC adapter or battery. I suspect its power supply is
malfunctioning. I opened it up, cleaned the dust and saw for any
broken connections, but did not find any. I presume the power supply
connections are wired deep inside due to which my cursory examination
could not find any issues). It is out of warranty and I am in India,
Asia where Dell does not have a authorized service center(which was
told to me when I spoke to them on phone).

I was using it a few days back when the power suddenly went off. The
battery started functioning and the power returned after a while after
which the machine started running on AC power. I could shut it down
normally, but when I tried to restart it two days later it won't.
Could the fact I did not
have a surge protector or Voltage stabilizer damaged the power supply?

On a side note I was running Win 2k(I know it is outdated), but don't
think that could be an issue. It's chipset is Intel Brookdale-G i845GL

Any clues on how to proceed would be highly appreciated.

Thanks a lot.

s wrote:
> My laptop(Dell Inspiron 1100) is 5 years old. Suddenly, its power
> supply seems to have died. It will not start(neither the CPU,hard
> drive or monitor LED's power up when I press the power on button)with
> the AC adapter or battery. I suspect its power supply is
> malfunctioning. I opened it up, cleaned the dust and saw for any
> broken connections, but did not find any. I presume the power supply
> connections are wired deep inside due to which my cursory examination
> could not find any issues). It is out of warranty and I am in India,
> Asia where Dell does not have a authorized service center(which was
> told to me when I spoke to them on phone).
>
> I was using it a few days back when the power suddenly went off. The
> battery started functioning and the power returned after a while after
> which the machine started running on AC power. I could shut it down
> normally, but when I tried to restart it two days later it won't.
> Could the fact I did not
> have a surge protector or Voltage stabilizer damaged the power supply?
>
> On a side note I was running Win 2k(I know it is outdated), but don't
> think that could be an issue. It's chipset is Intel Brookdale-G i845GL
>
> Any clues on how to proceed would be highly appreciated.
>
> Thanks a lot.

I have not succeeded in finding any good reference information
on how a laptop controls power. So that limits how much advice
I can offer, on what to do when you open up the insides of the
laptop.

A common failure point for laptops, is the power input jack on the
laptop motherboard. The pins on the jack can break away from the
PCB. Soldering them back may be of limited use, because they
can crack again later.

The power supply itself (external adapter), is likely a switching
power supply. It has to be, if it is going to be compact. Using
a multimeter, you can switch to the multimeter volts range and measure the
voltage on it. Ideally, a load test, drawing the rated power, would
also be useful, to determine whether the switcher is working properly.
It might produce the 19V or whatever is supposed to be on the output,
when there is no electrical load, but once you draw a couple amps, it
could switch off. It really depends if the external adapter has
protection against overload, and whether the adapter has become weak
from old age.

But, as for what is inside the laptop, I haven't seen enough detailed
pictures or schematics, to know what they use for a power supervisor,
and how that circuit responds to various conditions.

This picture, shows the insides of a regular ATX power supply. Notice
that the tops of some of the "blue cylinders", are covered with a
brown deposit. These are failed electrolytic capacitors. The vent on
the top is implemented as stamped lines in the aluminum, and if
pressure is present inside the cylinder, the lines split and the
material inside escapes without exploding. I recently opened an
ATX power supply here, and I found exactly this condition. Considering
the age of your computer, it is possible that some of the
cylinders (electrolytic capacitors) are leaking. They might
be present in the external adapter for example.

http://upload.wikimedia.org/wikipedi...4/PSU_Caps.jpg

If you catch the leakage soon enough, the capacitors can be replaced
with new ones. If the hardware is used, with the leaking capacitors
still in the circuit, it causes other components (MOSFETs, toriodal
transformers and the like) to fail. And it is a lot harder to
find replacements for some of the other items that can get damaged.
In my case, if I wanted to, I could repair my ATX power supply, because
it doesn't appear anything else is broken.

Paul

Thanks for the reply.


> A common failure point for laptops, is the power input jack on the
> laptop motherboard. The pins on the jack can break away from the
> PCB. Soldering them back may be of limited use, because they
> can crack again later.
How do I locate this power input jack? All I could see when I opened
it was the power button was above some sort
of switch. That had a small IC (Integrated Circuit) at its end which
was fitting into another one. I might not be describing it
accurately as I am not too tech-savvy so hopefully I can be excused if
I am bit vague.

> The power supply itself (external adapter), is likely a switching
> power supply. It has to be, if it is going to be compact. Using
> a multimeter, you can switch to the multimeter volts range and measure the
> voltage on it. Ideally, a load test, drawing the rated power, would
> also be useful, to determine whether the switcher is working properly.
> It might produce the 19V or whatever is supposed to be on the output,
> when there is no electrical load, but once you draw a couple amps, it
> could switch off. It really depends if the external adapter has
> protection against overload, and whether the adapter has become weak
> from old age.

The adapter shows a steady green light when connected to a wall outlet
which leads me to believe
it is working fine.

> This picture, shows the insides of a regular ATX power supply.
Does a laptop also have a similar ATX power supply like this one?

>Notice
> that the tops of some of the "blue cylinders", are covered with a
> brown deposit. These are failed electrolytic capacitors. The vent on
> the top is implemented as stamped lines in the aluminum, and if
> pressure is present inside the cylinder, the lines split and the
> material inside escapes without exploding. I recently opened an
> ATX power supply here, and I found exactly this condition. Considering
> the age of your computer, it is possible that some of the
> cylinders (electrolytic capacitors) are leaking. They might
> be present in the external adapter for example.

> http://upload.wikimedia.org/wikipedi...4/PSU_Caps.jpg
>
> If you catch the leakage soon enough, the capacitors can be replaced
> with new ones. If the hardware is used, with the leaking capacitors
> still in the circuit, it causes other components (MOSFETs, toriodal
> transformers and the like) to fail. And it is a lot harder to
> find replacements for some of the other items that can get damaged.
> In my case, if I wanted to, I could repair my ATX power supply, because
> it doesn't appear anything else is broken.

I am not sure I understand you fully, but do you mean I should open my
machine again, see if
I can find similar faulty capacitors and replace them?

On a side note I recall few days ago my monitor did not start up the
first time. Only when I pressed the
power switch very firmly did it start, but the power, hard disk led's
lit up fine the first time itself. But, this occurred when
I did not use my machine daily. When I started using it daily this
problem disappeared. Could this
have to do anything with my present problem(i.e. was that a symptom of
this major problem)?

Thanks again for your aid and time.

s wrote:
> Thanks for the reply.
>
>
>> A common failure point for laptops, is the power input jack on the
>> laptop motherboard. The pins on the jack can break away from the
>> PCB. Soldering them back may be of limited use, because they
>> can crack again later.

> How do I locate this power input jack? All I could see when I opened
> it was the power button was above some sort
> of switch. That had a small IC (Integrated Circuit) at its end which
> was fitting into another one. I might not be describing it
> accurately as I am not too tech-savvy so hopefully I can be excused if
> I am bit vague.

This article, in the section at the top, shows a person checking their
power input jack. (While the guy is using a multimeter which costs
more than $100, that isn't necessary. I have a $20 multimeter that is
good enough for quick checks, even if it is only 3% accurate.)

http://www.laptoprepair101.com/lapto...ps-and-tricks/

"In some laptops the power socket (DC jack) is soldered to the motherboard.
If the battery stops charging when you wiggle the power plug inside
the jack, either you have a bad power adapter (test it with a voltmeter)
or the power jack is broken or loose."

Where the jack is soldered to the motherboard, sometimes the connections
crack, leading to an intermittent connection. This is a picture of the
power input jack, soldered to the motherboard inside the laptop. That
"hole with the pin" is what you see on the outside of the laptop.

http://www.laptoprepair101.com/wp-im...k-soldered.jpg

>> The power supply itself (external adapter), is likely a switching
>> power supply. It has to be, if it is going to be compact. Using
>> a multimeter, you can switch to the multimeter volts range and measure the
>> voltage on it. Ideally, a load test, drawing the rated power, would
>> also be useful, to determine whether the switcher is working properly.
>> It might produce the 19V or whatever is supposed to be on the output,
>> when there is no electrical load, but once you draw a couple amps, it
>> could switch off. It really depends if the external adapter has
>> protection against overload, and whether the adapter has become weak
>> from old age.
>
> The adapter shows a steady green light when connected to a wall outlet
> which leads me to believe
> it is working fine.
>
>> This picture, shows the insides of a regular ATX power supply.

> Does a laptop also have a similar ATX power supply like this one?

No, I was illustrating one failure mechanism of switching power supplies.
That being, capacitors that prematurely fail. The adapter on a laptop
is smaller, uses some of the same principles as an ATX power supply,
but is going to look different inside if you opened it up. The switching
adapter on your laptop, only puts out one voltage, so it can be
simplified when compared to an ATX power supply. The ATX supply
has +12,+5,+3.3,+5VSB,-12V as outputs. Your laptop adapter might
be +19V only. (Laptop adapters vary from product to product and
are not interchangeable without due diligence. I've heard of
cases, where a laptop was damaged by using the wrong adapter.)

The status light won't tell you everything you need to know, but
I suppose if the light remains on steady while you are pressing the
power switch in the upper right corner of your laptop, that is a
good sign. That the adapter is not at fault. If the adapter light
winked, when the power switch was pressed, that would make you
suspicious of the adapter. I only mention this, if you don't have a
multimeter to do checks. Even with a multimeter, ideally you'd
want to to a load test on it, to see how healthy it really is.

>
> I am not sure I understand you fully, but do you mean I should open my
> machine again, see if
> I can find similar faulty capacitors and replace them?

The capacitors, if faulty, could be inside the adapter. Electrically,
any capacitors in there would experience the most stress. Inside the
laptop, the battery voltage (14V or some other voltage), will be
converted by another switching circuit, to lower voltages like 5V, 3.3V,
1.5V (Vcore for processor) and so on. So potentially, there are more
things that could go wrong inside the laptop. In a laptop, the
power conversion is being done it two steps - one step is via the
external adapter, but a second step is being done on the laptop
motherboard. And that is the part I don't have any details on.
The Vcore power conversion would be pretty conventional, but I
don't know what kind of chip the laptop uses to orchestrate
all of it.

As I explained before, the "power switch" on the top of the laptop, doesn't
switch the power directly. It sends a logic level signal to something
else. That something, switches the power state in response to pushing
the button. If you were to connect an ammeter to the power switch,
you won't see multiple amps flowing through it. So in that sense,
the power switch on your laptop, won't have the same issues as
say the switch on your vacuum cleaner. Switches of that type sometimes
wear out or burn out, because of the power level they are handling.
The switch on the laptop, lives in a relatively benign environment.
For the switch itself to fail, there would have to be a mechanical
issue (switch crushed by being pressed too hard).

>
> On a side note I recall few days ago my monitor did not start up the
> first time. Only when I pressed the
> power switch very firmly did it start, but the power, hard disk led's
> lit up fine the first time itself. But, this occurred when
> I did not use my machine daily. When I started using it daily this
> problem disappeared. Could this
> have to do anything with my present problem(i.e. was that a symptom of
> this major problem)?
>
> Thanks again for your aid and time.
>

In the LCD panel used as a display on the laptop, is another power
conversion device. It is called the inverter. It converts lower
voltage DC, into 700V to 1000 VAC, to run the CCFL lamps. The
cold cathode fluorescent lamps, are what makes the light for the
laptop screen. Sometimes, when a laptop fails, everything seems
to be booting as normal, but the screen remains dark. In that
case, it could be a bad inverter. But usually, you get some
preliminary warning, such as the laptop screen lights for a
few seconds, and then the light goes out. That happens, because
the inverter is able to run for a few seconds, but then decides
it is overloaded. Turning down the intensity setting of the
laptop, can change the symptoms a bit, but after a few
more weeks, the screen may no longer light. A replacement
inverter is one fix. Or a workaround is to connect an external
monitor to the VGA connector on the back of the laptop.

If the problem is inside the laptop, it is going to
require a high level of skill to track down, plus
disassembly of stuff that is easy to damage. All the
cabling inside the laptop is delicate, with cheesy
connectors that are easy to break. Once you decide
you're "going in" as it were, be prepared to never
see the laptop work again. You can always put the hard
drive from the laptop, in a 2.5" external USB enclosure,
if you want to get the files off it.

The power problem could be anywhere in the above described
power conversion steps. It could be an adapter problem.
It could be a problem inside the laptop, where the battery
voltage is converted to 5V, 3.3V, 1.5V. It could be
the component that supervises it all, on the motherboard.
Even in pictures of laptop motherboards, I haven't been
able to positively identify some of these subsystems.

Paul

Thanks again for the reply and great explanation.

On Oct 14, 3:02*am, Paul <nos...@needed.com> wrote:
> This article, in the section at the top, shows a person checking theirpowerinput jack. (While the guy is using a multimeter which costs
> more than $100, that isn't necessary. I have a $20 multimeter that is
> good enough for quick checks, even if it is only 3% accurate.)

Can the power input jack get damaged due to voltage fluctuations I
faced? And, how can I explain that during the power outage(and when
power was restored) it was fine and now it is having issues? Could the
damage been done at that point which is showing up now? Also, doesn't
an adapter protect the laptop from such voltage spikes? Was my mistake
not using a surge protector or voltage stabilizer? And if the jack is
damaged could that prevent starting of the laptop even from battery?

>. Even with a multimeter, ideally you'd
> want to to a load test on it, to see how healthy it really is.

The problem is here in India where I live such components are pricey
and it is hard to obtain
a good quality one(coupled with the fact nearly all local shops have a
no-return policy).





> As I explained before, the "powerswitch" on the top of the laptop, doesn't
> switch thepowerdirectly. It sends a logic level signal to something
> else. That something, switches thepowerstate in response to pushing
> the button. If you were to connect an ammeter to thepowerswitch,
> you won't see multiple amps flowing through it. So in that sense,
> thepowerswitch on your laptop, won't have the same issues as
> say the switch on your vacuum cleaner. Switches of that type sometimes
> wear out or burn out, because of thepowerlevel they are handling.
> The switch on the laptop, lives in a relatively benign environment.
> For the switch itself to fail, there would have to be a mechanical
> issue (switch crushed by being pressed too hard).

How can I test if the switch has failed or not? I recall it pressing
it too hard when
my monitor did not start up in the first time a few weeks back. Could
that have caused
some damage which is showing up now? If the switch is damaged can it
be replaced(and if so how
difficult/expensive it might be)?

> > On a side note I recall few days ago my monitor did not start up the
> > first time. Only when I pressed the
> >powerswitch very firmly did it start, but thepower, hard disk led's
> > lit up fine the first time itself. But, this occurred when
> > I did not use my machine daily. When I started using it daily this
> > problem disappeared. Could this
> > have to do anything with my present problem(i.e. was that a symptom of
> > this major problem)?
>


> In the LCD panel used as a display on the laptop, is anotherpower
> conversion device. It is called the inverter. It converts lower
> voltage DC, into 700V to 1000 VAC, to run the CCFL lamps. The
> cold cathode fluorescent lamps, are what makes the light for the
> laptop screen. Sometimes, when a laptop fails, everything seems
> to be booting as normal, but the screen remains dark. In that
> case, it could be a bad inverter. But usually, you get some
> preliminary warning, such as the laptop screen lights for a
> few seconds, and then the light goes out. That happens, because
> the inverter is able to run for a few seconds, but then decides
> it is overloaded. Turning down the intensity setting of the
> laptop, can change the symptoms a bit, but after a few
> more weeks, the screen may no longer light. A replacement
> inverter is one fix. Or a workaround is to connect an external
> monitor to the VGA connector on the back of the laptop.

So, my monitor not starting up initially indicated power was not
going to the LCD panel the first time I powered it or something else?

> If the problem is inside the laptop, it is going to
> require a high level of skill to track down, plus
> disassembly of stuff that is easy to damage. All the
> cabling inside the laptop is delicate, with cheesy
> connectors that are easy to break. Once you decide
> you're "going in" as it were, be prepared to never
> see the laptop work again. You can always put the hard
> drive from the laptop, in a 2.5" external USB enclosure,
> if you want to get the files off it.

Would a better idea be to show it to a service center, though I doubt
how much they can help and if
I can afford even their examination charges(they are around 5000rs or
100$ just to determine what is wrong
with your machine)

> Thepowerproblem could be anywhere in the above describedpowerconversion steps. It could be an adapter problem.
> It could be a problem inside the laptop, where the battery
> voltage is converted to 5V, 3.3V, 1.5V. It could be
> the component that supervises it all, on the motherboard.
> Even in pictures of laptop motherboards, I haven't been
> able to positively identify some of these subsystems.

Can the adapter problem prevent the laptop from starting even from
battery? And, can
motherboards fail due to voltage spikes(after the spike period has
passed like mine where it was
working fine when the power failed and came back and now giving me
issues)?

THANKS A LOT for your responses and time. I am indeed grateful.
> * * Paul

s wrote:
> Thanks again for the reply and great explanation.
>
> Can the power input jack get damaged due to voltage fluctuations I
> faced?

No. Typically a power jack is damaged by mechanical forces.
Such as tripping on the cord and forcefully pulling the
plug out. That can break the solder connections where the
jack is fastened to the motherboard.

> And, how can I explain that during the power outage(and when
> power was restored) it was fine and now it is having issues?

A good question. I don't have an answer.

> Could the damage been done at that point which is showing up now?

It could, but as you explained yourself, the fact that the machine
worked after the failure, but failed to start later, is a bit
strange and not a coincidence.

> Also, doesn't an adapter protect the laptop from such voltage spikes?

Not in any absolute sense. Even a UPS equipped with surge protection
devices, is not always able to prevent problems at its output. The
adapter on the laptop has an emphasis on portability and light
weight, so may not contain all the circuitry the owner would hope
for. For example, some seem to have poor hold-up time, the ability
to resist a short (16 millisecond) power outage.

> Was my mistake not using a surge protector or voltage stabilizer?

Every location has its own set of conditions. I used to work at a
place, where there were short outages every day. The company ended
up buying a UPS for every employee, so no work would be lost. Other
locations may have clean power. Personally, I use a UPS and a surge
protection strip where I am now, and have only had one expensive
monitor damaged, even with that protection. There are no certainties
with electricity.

> And if the jack is damaged could that prevent starting of the
> laptop even from battery?

That is the part of the circuit that I need a schematic for. There
should be some transistors or MOSFETs in the path, to switch the adapter
or the battery. I don't think there are any relays. You would think,
if the battery still has a charge, that the circuit would still operate.
So something is wrong with whatever supervises these functions, and
that is the part I don't have any diagrams for. I've tried to find
chip specifications for power management chips, but wasn't successful
at finding anything for a laptop. As with many high tech things, in
order to find answers, you have to use the right terminology, and
so far, I haven't succeeded at figuring out what they might call
the function.

>
> The problem is here in India where I live such components are pricey
> and it is hard to obtain
> a good quality one(coupled with the fact nearly all local shops have a
> no-return policy).
>

If the battery has a charge, disconnect the AC adapter, and test the
laptop again. If it won't start, then the adapter is not preventing it.

>
> How can I test if the switch has failed or not? I recall it pressing
> it too hard when
> my monitor did not start up in the first time a few weeks back. Could
> that have caused
> some damage which is showing up now? If the switch is damaged can it
> be replaced(and if so how
> difficult/expensive it might be)?

Did the switch work, after you pressed it too hard ? How many times
did it work successfully after that event ? I would think, it is not
a coincidence, that you've had a problem after a power failure, and
that is more likely to be the source of the stress.

Ideally, to test the switch fully, you would disconnect it from the
circuit. But since it is part of a logic circuit, in this case it
is probably sufficient to monitor the voltage on the non-grounded
end of the switch, and see that there is a full logic swing. This
is an example of a typical interface. The switch type is "momentary
contact", and would normally be open circuit. (On a desktop computer,
two of these circuits are used, one for "power" and one for "reset".)
The resistor is a "pullup resistor", and limits the current flow when
the switch is closed. The signal going to the logic circuit, can then have
two voltage values, either V+ or zero volts. If you saw intermediate
values, like 1/2 * V, then you would suspect a problem. The signal
should be binary, and have two well defined states.

V+
|
resistor
|
+---------------> to logic circuit
| Voltage = V+ when user is not pressing the button
x Voltage = zero volts, when user presses the burron
\
x
|
Ground


>
> So, my monitor not starting up initially indicated power was not
> going to the LCD panel the first time I powered it or something else?
>

To me, that indicates that the inverter did not start for some
reason. Some inverters have a signal that controls the intensity,
and if that signal said "zero intensity" then perhaps the inverter
would not start. So perhaps some other part of the laptop could
have done that. The function could be partially controlled
by a power supervisor circuit, that decides when the inverter
should be turned on.

>
> Would a better idea be to show it to a service center, though I doubt
> how much they can help and if
> I can afford even their examination charges(they are around 5000rs or
> 100$ just to determine what is wrong
> with your machine)
>

Even here, there are certain services which we refer to as
"highway robbery". In fact, some laptop repair facilities
here, charge $200 to "look at it", without fixing anything.
So even the people here, think twice before approaching a
repair facility. By comparison, if I take my car to a mechanic,
he might charge $30 to $60 for a simple diagnosis (if the car
had to be extensively disassembled, it would cost more). So
laptop repair is priced above what you would expect.

I see no evidence to suggest that the laptop repair people are
skilled. Many times, a poster here will say "they told me it
needs a new motherboard". Since that is essentially all the
important working parts inside, they can blindly tell the customers
that, perhaps without even opening up the unit.

By comparison, people who work in TV repair shops, know a lot
about the circuits they work on. They work at the component level,
and can repair things without replacing the entire TV. I suspect
laptop repair, requires less skill, if all repairs mean
"replacing the motherboard". I don't even think the average
repair facility (like a Dell authorized one) would solder the
power jack if it was loose. They're replace the entire
motherboard instead.

So the treatment you would receive at your repair facility,
would be just as poor as the treatment we get.

>
> Can the adapter problem prevent the laptop from starting even from
> battery?

Disconnect the adapter and test with the battery. You say the
battery is still charged, so that should be a good test. If
it still won't start, then the problem is more likely to
be inside the laptop.

> And, can
> motherboards fail due to voltage spikes(after the spike period has
> passed like mine where it was
> working fine when the power failed and came back and now giving me
> issues)?
>
> THANKS A LOT for your responses and time. I am indeed grateful.

I think the entire sequence of events has significance. But because
I don't know how the power supervision circuit works, I cannot say
if there is a latent failure mechanism possible or not. I doubt
it just ran long enough, to die on the next restart. Maybe the
circuit thinks the computer is still running for example, and is
not following the correct startup sequence. I'd suggest removing
the CMOS battery, if I thought it was tied into that circuit, but
I don't think it is.

The power supervisor should be reset, when both the main battery
is pulled, and the adapter is disconnected. Leave the battery
out for an hour, so any charge inside has drained, just to be
on the safe side. After that, put the battery back, and try it.
If it won't start, I don't see what else can be tried externally,
so you'd need to trace where the power goes inside the thing.

I've tried tracing some circuits on a desktop motherboard, and
it takes hours to do it, for even the simplest functions. That
is why a schematic is so important, for efficient debugging. I
have fixed things without a schematic, but it isn't an easy
or a sure thing.

Paul

On Tue, 14 Oct 2008 05:48:26 -0700 (PDT), s
<s@mailinator.com> wrote:


>How can I test if the switch has failed or not? I recall it pressing
>it too hard when
>my monitor did not start up in the first time a few weeks back. Could
>that have caused
>some damage which is showing up now? If the switch is damaged can it
>be replaced(and if so how
>difficult/expensive it might be)?
>

>
>So, my monitor not starting up initially indicated power was not
>going to the LCD panel the first time I powered it or something else?
>

In case there might have been power surge damage, disconnect
all things possible while both the battery and AC adapter
are unplugged. This means take out the memory, hard drive,
optical drive, and then try powering it on... not trying to
get it to POST and boot, just seeing whether it will then
turn on at all. If this does not allow power-on, proceed to
unplug the lead to the LCD inverter board, being mindful of
where you leave the stray wire as you don't want it shorting
out on anything, then try to power it on again.

Proceed to unplug as many other things as possible, and
lastly also try taking the processor out although if you
take the heatsink off you will need to clean off the
original thermal interface material and put fresh thermal
compound on before remounting the heatsink later.

With as much as possible disconnected, again try to power on
with the AC adapter connected, then try with it disconnected
and only using the battery. Is it possible you had ran the
laptop long enough that the battery drained down to the
point where it now has insufficient charge to power on the
laptop?

If that is possible I would wonder if the AC adapter had
simply failed even though the light is still on. Having a
multimeter available to measure the voltage produced by the
AC adapter while it is plugged into the mainboard and you're
trying to turn the laptop on might be a useful reading.




>> If the problem is inside the laptop, it is going to
>> require a high level of skill to track down, plus
>> disassembly of stuff that is easy to damage. All the
>> cabling inside the laptop is delicate, with cheesy
>> connectors that are easy to break. Once you decide
>> you're "going in" as it were, be prepared to never
>> see the laptop work again. You can always put the hard
>> drive from the laptop, in a 2.5" external USB enclosure,
>> if you want to get the files off it.

While it is true the cabling and connectors are fragile, if
one takes their time it should not be exceptional to have no
damage from disassembly, frankly I think a more common
problem is when someone mangles the plastic case because
they are having trouble prying it open.


>
>Would a better idea be to show it to a service center, though I doubt
>how much they can help and if
>I can afford even their examination charges(they are around 5000rs or
>100$ just to determine what is wrong
>with your machine)

At this point it is unlikely your 5 year old laptop is worth
the cost to repair it. If there are auctions in your area
or a laptop or computer repair shop nearby you might see if
you can sell the laptop for parts, though first you might
want to take the hard drive out and keep it, or copy off any
important data and then erase it so your data is not in
someone else's hand if you include the hard drive with the
laptop. Typically a desktop-laptop adapter can be used for
this purpose, to do that in a desktop system.



>
>> Thepowerproblem could be anywhere in the above describedpowerconversion steps. It could be an adapter problem.
>> It could be a problem inside the laptop, where the battery
>> voltage is converted to 5V, 3.3V, 1.5V. It could be
>> the component that supervises it all, on the motherboard.
>> Even in pictures of laptop motherboards, I haven't been
>> able to positively identify some of these subsystems.
>
>Can the adapter problem prevent the laptop from starting even from
>battery?

It seems very unlikely, but ultimately it would be good to
test the AC adapter, multimeter measurements to confirm it
is outputting the correct voltage while plugged into the
laptop. Try it with and without the battery installed in
the laptop.


>And, can
>motherboards fail due to voltage spikes(after the spike period has
>passed like mine where it was
>working fine when the power failed and came back and now giving me
>issues)?

Yes, power surge damage can be subtle and a system can keep
working fine only to fail later.

On Tue, 14 Oct 2008 11:45:20 -0400, Paul <nospam@needed.com>
wrote:

<snip>


>That is the part of the circuit that I need a schematic for. There
>should be some transistors or MOSFETs in the path, to switch the adapter
>or the battery. I don't think there are any relays. You would think,
>if the battery still has a charge, that the circuit would still operate.
>So something is wrong with whatever supervises these functions, and
>that is the part I don't have any diagrams for. I've tried to find
>chip specifications for power management chips, but wasn't successful
>at finding anything for a laptop. As with many high tech things, in
>order to find answers, you have to use the right terminology, and
>so far, I haven't succeeded at figuring out what they might call
>the function.


While not a schematic, this article gives a few hints.
Regardless, there's no way to be sure of the specific
circuit in the laptop without tracing it out since the
manufacturer isn't going to give out a schematic.

http://findarticles.com/p/articles/m...28/ai_64834920

Otherwise, probing around the power jack should indicate if
it's shorting something it shouldn't, though when they are
loose it tends to be visually obvious. A link to a really
high resolution picture(s) of the laptop mainboard might
help.

Thanks a lot for the reply and explanations.

On Oct 14, 8:45*pm, Paul <nos...@needed.com> wrote:

> No. Typically apowerjack is damaged by mechanical forces.
> Such as tripping on the cord and forcefully pulling the
> plug out. That can break the solder connections where the
> jack is fastened to the motherboard.

I don't this occurred.



> > The problem is here in India where I live such components are pricey
> > and it is hard to obtain
> > a good quality one(coupled with the fact nearly all local shops have a
> > no-return policy).
>
> If the battery has a charge, disconnect the AC adapter, and test the
> laptop again. If it won't start, then the adapter is not preventing it.

One of my friend who has a same model laptop could get it to function
with my adapter(alone, he removed his battery laptop) and my
battery(removing
adapter). This suggests my laptop and battery could be working fine
and
the issue is somewhere inside the motherboard.


> Did the switch work, after you pressed it too hard ? How many times
> did it work successfully after that event ? I would think, it is not
> a coincidence, that you've had a problem after apowerfailure, and
> that is more likely to be the source of the stress.

Yes, it worked. I did not use the machine for some 10 days. Then to
start
the monitor I had to press it quite hard. Then, when I started using
it
daily I pressed the switch normally and the monitor started up.

> Ideally, to test the switch fully, you would disconnect it from the
> circuit. But since it is part of a logic circuit, in this case it
> is probably sufficient to monitor the voltage on the non-grounded
> end of the switch, and see that there is a full logic swing. This
> is an example of a typical interface. The switch type is "momentary
> contact", and would normally be open circuit. (On a desktop computer,
> two of these circuits are used, one for "power" and one for "reset".)
> The resistor is a "pullup resistor", and limits the current flow when
> the switch is closed. The signal going to the logic circuit, can then have
> two voltage values, either V+ or zero volts. If you saw intermediate
> values, like 1/2 * V, then you would suspect a problem. The signal
> should be binary, and have two well defined states.

I wish I had your background in electronics! Your knowledge in this
matter is
impressive indeed! I can understand what you are saying, but could
not have thought of it myself.



> I'd suggest removing
> the CMOS battery, if I thought it was tied into that circuit, but
> I don't think it is.

How do I find the CMOS battery? When I opened it a preliminary
examination did not reveal that to me.

> Thepowersupervisor should be reset, when both the main battery
> is pulled, and the adapter is disconnected. Leave the battery
> out for an hour, so any charge inside has drained, just to be
> on the safe side. After that, put the battery back, and try it.

This I did already before I started posting here and it did not help.
I actually did this when for some reason my machine
freezes(and even the power button does not work). But, those
situations were pretty rare.

> If it won't start, I don't see what else can be tried externally,
> so you'd need to trace where thepowergoes inside the thing.

For that I would need a vast knowledge like you on laptop hardware
which
unfortunately I do not possess. For me, it seems going to the
service center is the only option and hope I don't get exploited
too badly. I opened it, but the whole motherboard looks like
some Byzantine maze to me and I doubt I could begin to
fathom how and where power flows after the power switch is
pressed.

Thanks for all your responses and help.

Thanks for your reply.

On Oct 15, 12:20*am, kony <s...@spam.com> wrote:

> In case there might have beenpowersurge damage, disconnect
> all things possible while both the battery and AC adapter
> are unplugged. *This means take out the memory, hard drive,
> optical drive, and then try powering it on... not trying to
> get it to POST and boot, just seeing whether it will then
> turn on at all.

I did this and nothing occurred.

>*If this does not allowpower-on, proceed to
> unplug the lead to the LCD inverter board, being mindful of
> where you leave the stray wire as you don't want it shorting
> out on anything, then try topowerit on again. *

How do I unplug the LCD inverter board? I have never opened a laptop
monitor before?

> Proceed to unplug as many other things as possible, and
> lastly also try taking the processor out although if you
> take the heatsink off you will need to clean off the
> original thermal interface material and put fresh thermal
> compound on before remounting the heatsink later.

Unlikely I can do it with my limited knowledge and more difficult
is finding the proper thermal compound(although I don't know even
which compound you are alluding to). I know lot less than the average
laptop
user in such matters.

> With as much as possible disconnected, again try topoweron
> with the AC adapter connected, then try with it disconnected
> and only using the battery. *Is it possible you had ran the
> laptop long enough that the battery drained down to the
> point where it now has insufficient charge topoweron the
> laptop? *

No, the power failed for some 25mins. I ran it on battery for some
15mins, then turned it
off. The battery at that point had a charge to run it for another
75mins as indicated by
the battery icon when I turned off the computer.

> If that is possible I would wonder if the AC adapter had
> simply failed even though the light is still on. *Having a
> multimeter available to measure the voltage produced by the
> AC adapter while it is plugged into the mainboard and you're
> trying to turn the laptop on might be a useful reading.

I could not gather a multimeter, but feel if my adapter can
power my friends laptop(whose battery was removed) it is working fine
like my battery(which could also power my friends machine which was
disconnected from the AC adapter).


> While it is true the cabling and connectors are fragile, if
> one takes their time it should not be exceptional to have no
> damage from disassembly, frankly I think a more common
> problem is when someone mangles the plastic case because
> they are having trouble prying it open.

Depends on the skill level of the person. Possible for you, Paul and
similar such folks, but for someone like me who is trying it
first time without any help it is somewhat tough.

>*Typically a desktop-laptop adapter can be used for
> this purpose, to do that in a desktop system.

Thanks. I will do that.


> Yes,powersurge damage can be subtle and a system can keep
> working fine only to fail later.

So, my mistake was gross negligence in plugging my adapter into the
wall outlet instead of using a surge protector? Or could the age
also have compounded the problem. I have seen such
outages before, but this is the one which has
left my machine in such a state. The earlier ones
did not seem to affect it.

Thanks for your reply and suggestions.

> Otherwise, probing around thepowerjack should indicate if
> it's shorting something it shouldn't, though when they are
> loose it tends to be visually obvious. * A link to a really
> high resolution picture(s) of the laptop mainboard might
> help.

I did the probing and it looks fine. I will try to get a picture soon
of
the laptop motherboard. Thanks for your aid and time

On Oct 15, 11:32*am, s <s...@mailinator.com> wrote:
> So, my mistake was gross negligence in plugging my adapter into the
> wall outlet instead of using asurgeprotector?

If a destructive surge occured, then why is your AC power supply
(adaptor) still working? To say why failure happened, first identify
what is damaged. Sounds like the best you will conclude is a
motherboard defect. Almost all defects have no visible indication.
In the other newsgroup where your post is duplicated, Christopher
accurately described how power is distributed on the motherboard. To
trace this 'no power' fault on the motherboard, use facts that
Christopher provided.

Let's see. You connected that computer to 120 VAC power. If
voltage goes higher, then other household appliances and light bulbs
get damaged. But your computer is rated to work just perfectly even
when AC mains are 240 volts. If excessive voltage (a surge) harmed a
240 volt computer, then why are all those other "only 120 volt"
appliances working just fine?

Most likely reason for failure is something mechanical or a
manufacturing defect inside some component. Such failures rarely
leave any visual indication.

On Wed, 15 Oct 2008 08:32:12 -0700 (PDT), s
<s@mailinator.com> wrote:


>How do I unplug the LCD inverter board? I have never opened a laptop
>monitor before?

There will be at least leads to the CCFL lighting which you
can trace back to the inverter board and unplug, and a cable
for the screen itself (and maybe for a wifi antenna). Just
follow the leads and unplug the right one. You should be
able to tell the antenna lead from inverter board as it goes
to the NIC, and the screen cable is typically a (mylar?)
ribbon.


>
>> Proceed to unplug as many other things as possible, and
>> lastly also try taking the processor out although if you
>> take the heatsink off you will need to clean off the
>> original thermal interface material and put fresh thermal
>> compound on before remounting the heatsink later.
>
>Unlikely I can do it with my limited knowledge and more difficult
>is finding the proper thermal compound(although I don't know even
>which compound you are alluding to). I know lot less than the average
>laptop
>user in such matters.

If you have a mom-n-pop tv/electronics repair shop around,
that might be your best option to "hope" for an affordable
repair - or at least only a small bench fee to be told it
won't be an affordable repair, so that is a roughly $50 to
$100 gamble on what is wrong and if it's cost effective to
fix it. While many places cringe at the idea of a piece of
equipment the customer has dismantled, you might want to
take it to them already in the open state you have it so
they don't have to dismantle it themselves.

If it's more than a cheap discrete component replacement it
is probably not worth repairing at this point, a repair more
invovled than that could easily be over $180 while the
laptop itself is near end of average life at the 5 year
point, could easily need new CCFL tubes and hard drive, have
other typical wear, etc.



>I could not gather a multimeter, but feel if my adapter can
>power my friends laptop(whose battery was removed) it is working fine
>like my battery(which could also power my friends machine which was
>disconnected from the AC adapter).

Yes, it does seem you have ruled out the AC adapter and
battery.


>> Yes,powersurge damage can be subtle and a system can keep
>> working fine only to fail later.
>
>So, my mistake was gross negligence in plugging my adapter into the
>wall outlet instead of using a surge protector?

Not necessarily, yes a surge protector is a good idea but
whether that is the route the surge came in on is another
matter, and some surge protectors aren't quite comprehensive
protection. You could even be the unlucky one in a million
who just happened to have their laptop fail right after a
power outtage, if it were new I'd think it unlikely but at 5
years old the likelihood of a failure goes up every day.


Or could the age
>also have compounded the problem. I have seen such
>outages before, but this is the one which has
>left my machine in such a state. The earlier ones
>did not seem to affect it.
>
>Thanks for your reply and suggestions.

I'm still leaning towards my prior suggestion if you can't
find the fault yourself - sell it whole or part it out to
recoup some of the loss to apply towards a new laptop.