"kony" <spam@spam.com> wrote in message
news:biomi3h6v17ncrddnm62srm8uli4h0foc4@4ax.com...
> On Fri, 2 Nov 2007 14:24:34 -0000, "GT"
> <ContactGT_remove_@hotmail.com> wrote:
>
>>"GT" <ContactGT_remove_@hotmail.com> wrote in message
>>news:0126a38a$0$3687$c3e8da3@news.astraweb.com.. .
>>>I would like to start this with "a friend of mine...", but I can't!
>>>
>>> I have a 1 year old Dell Inspiron 6400 and decided to pour a full cup of
>>> fresh, just boiled tea over it. Sounds silly to mention it, but no milk
>>> or
>>> sugar, just a fresh slice of lemon. Before I could even whip the power
>>> cable out of the back, the machine turned itself off instantly. I pulled
>>> the battery after a moment to limit any further power related damage.
>>> The
>>> memory compartment underneath seems to be dry. The hard disk seems to be
>>> dry - removed that about 5 minutes after the event.
>>
>>Completely overhauled the box, inspecting and drynig as I went. The only
>>tea
>>damaged parts are the keyboard, mousepad and battery compartment. Some
>>liquid must have reached the battery connector as the power went off
>>immediately following the tea incident. I have dried all the parts and
>>left
>>it all over night. No circuitry has been touched by the liquid, other than
>>whatever is under the keyboard keys and under the mousepad and buttons.
>>
>>However, it is dead. Power from battery or mains gives nothing. No fan
>>noise, no lights, nothing. I strongly suspect that damage was done when
>>the
>>tea hit the battery contacts, but don't know where to begin in diagnosing
>>the problem. Will probably just phone Dell, explain and see what they
>>recommend. Its only just over 1 year old (1 year warranty!), but a repair
>>might be more costly than a new machine!
>>
>
> Do you have a mulltimeter? If not, now is a good excuse
> to get one. Even some cheap $20 generic is a very useful
> tool for many purposes, it need not be a $200 Fluke.
>
> Keep the battery out, plug the AC adapter in and trace the
> power from the onboard (or occasionally separate power
> board) section. Basically you would take meter probes and
> follow the power path, from input all the way to some
> chips.
Odd... Plugged in the power adapter and the light comes on (on the adaptor).
Plug that into the laptop and the power light dies on the power adaptor and
the laptop does nothing. There is no power available (instantly) to trace
through the laptop! Sticking the multimeter into the end of the power
adapter wire shows the correct 19.5v, but 0 amps. Seems like the power
adapter is shot! We have another inspiron 6400 at work, so I will figure out
if the adapter is shot by using it on the working PC on Monday. What I am
reluctant to do is try the working power adapter in the broken laptop, as it
might blow the working adapter!
What it feels like is that the laptop 'trips' the power adapter when it is
connected to the laptop, but of course this doesn't explain the 0 amps
readout, unless my multimeter is broken. This is possible as it has
different connections for current and voltage testing.
The laptop battery is fully charged and the laptop doesn't work from that
either, so there is still definitely a problem in the laptop, however, I
rarely use (and could live without) the battery.
GT wrote:
>
> Odd... Plugged in the power adapter and the light comes on (on the adaptor).
> Plug that into the laptop and the power light dies on the power adaptor and
> the laptop does nothing. There is no power available (instantly) to trace
> through the laptop! Sticking the multimeter into the end of the power
> adapter wire shows the correct 19.5v, but 0 amps. Seems like the power
> adapter is shot! We have another inspiron 6400 at work, so I will figure out
> if the adapter is shot by using it on the working PC on Monday. What I am
> reluctant to do is try the working power adapter in the broken laptop, as it
> might blow the working adapter!
>
> What it feels like is that the laptop 'trips' the power adapter when it is
> connected to the laptop, but of course this doesn't explain the 0 amps
> readout, unless my multimeter is broken. This is possible as it has
> different connections for current and voltage testing.
>
> The laptop battery is fully charged and the laptop doesn't work from that
> either, so there is still definitely a problem in the laptop, however, I
> rarely use (and could live without) the battery.
>
>
You make a current measurement, in series with one rail, like this:
To make a current measurement, normally you'd have to hack into the
cable, break one wire, and insert the multimeter on the current
range, to measure the current in the wire. Currents, you measure
in series - voltage you measure in parallel.
Don't even go near the current measurement function, unless you know
how it works. The current measurement terminals on the multimeter, are
a "dead short". If you shove the multimeter, set on current, and wires
plugged to the "current holes" on the meter, into a power adapter,
that shorts out the adapter, and potentially blows the protection
fuse inside the multimeter, or the fuse inside the device being
tortured.
This is why the "current measurement holes" on the multimeter, are
separate from the "voltage/ohms" holes. It is to prevent accidents.
As a result of these details, I hardly ever use the current ranges
on my digital multimeter.
I have a "clamp-on" DC ammeter, but even that requires physical
separation of the conductors, to get a reading. If you clamp one
of those meters, around the pair of wires in the adapter cable
shown above, the reading would be zero. If the jaws are clamped
around just one of the two wires, you get a valid current reading.
Measuring current is tricky, and you have to know what you're doing.
Otherwise, you'll be replacing the fuse inside the multimeter, a lot :-)
On Sun, 4 Nov 2007 22:36:01 -0000, "GT"
<ContactGT_remove_@hotmail.com> wrote:
>"kony" <spam@spam.com> wrote in message
>news:biomi3h6v17ncrddnm62srm8uli4h0foc4@4ax.com.. .
>> On Fri, 2 Nov 2007 14:24:34 -0000, "GT"
>> <ContactGT_remove_@hotmail.com> wrote:
>>
>>>"GT" <ContactGT_remove_@hotmail.com> wrote in message
>>>news:0126a38a$0$3687$c3e8da3@news.astraweb.com. ..
>>>>I would like to start this with "a friend of mine...", but I can't!
>>>>
>>>> I have a 1 year old Dell Inspiron 6400 and decided to pour a full cup of
>>>> fresh, just boiled tea over it. Sounds silly to mention it, but no milk
>>>> or
>>>> sugar, just a fresh slice of lemon. Before I could even whip the power
>>>> cable out of the back, the machine turned itself off instantly. I pulled
>>>> the battery after a moment to limit any further power related damage.
>>>> The
>>>> memory compartment underneath seems to be dry. The hard disk seems to be
>>>> dry - removed that about 5 minutes after the event.
>>>
>>>Completely overhauled the box, inspecting and drynig as I went. The only
>>>tea
>>>damaged parts are the keyboard, mousepad and battery compartment. Some
>>>liquid must have reached the battery connector as the power went off
>>>immediately following the tea incident. I have dried all the parts and
>>>left
>>>it all over night. No circuitry has been touched by the liquid, other than
>>>whatever is under the keyboard keys and under the mousepad and buttons.
>>>
>>>However, it is dead. Power from battery or mains gives nothing. No fan
>>>noise, no lights, nothing. I strongly suspect that damage was done when
>>>the
>>>tea hit the battery contacts, but don't know where to begin in diagnosing
>>>the problem. Will probably just phone Dell, explain and see what they
>>>recommend. Its only just over 1 year old (1 year warranty!), but a repair
>>>might be more costly than a new machine!
>>>
>>
>> Do you have a mulltimeter? If not, now is a good excuse
>> to get one. Even some cheap $20 generic is a very useful
>> tool for many purposes, it need not be a $200 Fluke.
>>
>> Keep the battery out, plug the AC adapter in and trace the
>> power from the onboard (or occasionally separate power
>> board) section. Basically you would take meter probes and
>> follow the power path, from input all the way to some
>> chips.
>
>Odd... Plugged in the power adapter and the light comes on (on the adaptor).
>Plug that into the laptop and the power light dies on the power adaptor and
>the laptop does nothing. There is no power available (instantly) to trace
>through the laptop! Sticking the multimeter into the end of the power
>adapter wire shows the correct 19.5v, but 0 amps. Seems like the power
>adapter is shot! We have another inspiron 6400 at work, so I will figure out
>if the adapter is shot by using it on the working PC on Monday. What I am
>reluctant to do is try the working power adapter in the broken laptop, as it
>might blow the working adapter!
>
>What it feels like is that the laptop 'trips' the power adapter when it is
>connected to the laptop, but of course this doesn't explain the 0 amps
>readout, unless my multimeter is broken. This is possible as it has
>different connections for current and voltage testing.
>
>The laptop battery is fully charged and the laptop doesn't work from that
>either, so there is still definitely a problem in the laptop, however, I
>rarely use (and could live without) the battery.
>
To measure current you have to place the ammeter in series with the
load.
On Sun, 4 Nov 2007 22:36:01 -0000, "GT"
<ContactGT_remove_@hotmail.com> wrote:
>> Do you have a mulltimeter? If not, now is a good excuse
>> to get one. Even some cheap $20 generic is a very useful
>> tool for many purposes, it need not be a $200 Fluke.
>>
>> Keep the battery out, plug the AC adapter in and trace the
>> power from the onboard (or occasionally separate power
>> board) section. Basically you would take meter probes and
>> follow the power path, from input all the way to some
>> chips.
>
>Odd... Plugged in the power adapter and the light comes on (on the adaptor).
>Plug that into the laptop and the power light dies on the power adaptor and
>the laptop does nothing. There is no power available (instantly) to trace
>through the laptop!
Take your meter and measure continuity (and then resistance)
across the PSU input jack contacts. If you can't get the
meter probes into the jack you will have to trace it back on
the PCB. The goal is to determine if the PSU is shot or
just being pulled down to a shorted output.
Another test you could do is (assuming PSU still seems
operational when not plugged into laptop) leave PSU
disconnected from laptop and load it somehow, the load
depending on it's voltage rating. If the PSU light no
longer lights up when disconnected from AC, disconnected
from laptop for a few minutes, then plugged back into AC, it
would seem either the PSU was dying or this new short
condition has done it in, but maybe it's fine so I write the
next paragraph about it...
Supposing it's a 14.4V supply that might allow connecting a
car headlight to it, though much higher voltage and you
wouldn't expect the car headlight to last for long so some
power resistors might be used, the goal being to put at
least a fair load on the PSU, say half of it's rated output
give or take. Something like 4 parallel series of 2, 22
Ohm, 10W power resistors would be in the ballpark as a rough
guess but do the math to be sure I didn't brain ****. Maybe
5 parallel series if the PSU is fairly low voltage relative
to most laptop PSU.
I would wonder if there is still some water or tea in the
laptop somewhere, and with it pulling enough current to shut
off the PSU (if the PSU were still good), I'd be doubly sure
to check the laptop fuses at some point as such a short
condition seems like it ought to burn a fuse else why would
they be there at all... maybe just overrated or the short
was before a fuse in the path.
>Sticking the multimeter into the end of the power
>adapter wire shows the correct 19.5v, but 0 amps. Seems like the power
>adapter is shot!
I'm not sure exactly how you're taking this reading but as
Paul and Andy mentioned the multimeter would have to be in
series with the power, either positive or negative lead is
broken and the meter leads are placed in series so the
current flows through the meter.
At this point, IF I understand what you are describing in
that you had the meter probes in the current measuring
jacks, you had the PSU unplugged from the laptop, you put
one meter probe on the PSU positive contact (probably a DC
barrel connector?) and one meter probe on the negative PSU
contact, then you have probably almost instantly blown a
fuse in the meter (or worse, if it was a really dirt cheap
meter they might have left out the fuse entirely but I
though there was some UL requirement for a fuse(?).
Regardless, if your meter no longer seems able to measure
the current of anything the fuse is probably blown. A
random guess is it has around 500mA rating as when there's
another fuse it is usually closer to 10A or more and I doubt
the laptop PSU can generate over 10A.
>We have another inspiron 6400 at work, so I will figure out
>if the adapter is shot by using it on the working PC on Monday. What I am
>reluctant to do is try the working power adapter in the broken laptop, as it
>might blow the working adapter!
That's why I suggest trying questionable adapter by itself,
and measure for continuity/resistance at the laptop power
jack, while the PSU is not connected to it (nor the
battery).
If you plug the PSU in and the light comes on, I would tend
to guess the adapter is ok and the laptop is shorting it out
but this is just a first impression.
>What it feels like is that the laptop 'trips' the power adapter when it is
>connected to the laptop, but of course this doesn't explain the 0 amps
>readout, unless my multimeter is broken. This is possible as it has
>different connections for current and voltage testing.
I suspect Andy, Paul and I have covered the current issue.
It's an aggravation to have to replace a fuse but most of
the tests you could do don't necessarily require current
checking so for now it's not a problem per se, you can still
measure whether the incoming voltage remains near the spec'd
level and the continuity of the input + - contacts... which
of course should have a very high resistance reading between
them if any.
>
>The laptop battery is fully charged and the laptop doesn't work from that
>either, so there is still definitely a problem in the laptop, however, I
>rarely use (and could live without) the battery.
>
If you're unsure if it's dry then point a fan at it while
open for a couple days, or it may be time to either take it
apart and agitate the board in warm detergent water then
rinse and dry for a few more days, or before that perhaps
unplug all non-essential things in case some integrated
peripheral is shorting out. By nonessential I mean only
goal is to get laptop to turn on and post, nevermind being
able to use it so even the touchpad should be disconnected
until it shows signs of life again.
"Paul" <nospam@needed.com> wrote in message news:fglopm$otb$1@aioe.org...
> GT wrote:
>>
>> Odd... Plugged in the power adapter and the light comes on (on the
>> adaptor). Plug that into the laptop and the power light dies on the power
>> adaptor and the laptop does nothing. There is no power available
>> (instantly) to trace through the laptop! Sticking the multimeter into the
>> end of the power adapter wire shows the correct 19.5v, but 0 amps. Seems
>> like the power adapter is shot! We have another inspiron 6400 at work, so
>> I will figure out if the adapter is shot by using it on the working PC on
>> Monday. What I am reluctant to do is try the working power adapter in the
>> broken laptop, as it might blow the working adapter!
>>
>> What it feels like is that the laptop 'trips' the power adapter when it
>> is connected to the laptop, but of course this doesn't explain the 0 amps
>> readout, unless my multimeter is broken. This is possible as it has
>> different connections for current and voltage testing.
>>
>> The laptop battery is fully charged and the laptop doesn't work from that
>> either, so there is still definitely a problem in the laptop, however, I
>> rarely use (and could live without) the battery.
>
> You make a current measurement, in series with one rail, like this:
>
> A.C.
> Adapter ----------------x <--- multimeter_current_setup --->
> x-------> laptop
> D.C.
> input
>
> Output ------------------------------------------------------------->
> connector
>
> To make a current measurement, normally you'd have to hack into the
> cable, break one wire, and insert the multimeter on the current
> range, to measure the current in the wire. Currents, you measure
> in series - voltage you measure in parallel.
>
> Don't even go near the current measurement function, unless you know
> how it works. The current measurement terminals on the multimeter, are
> a "dead short". If you shove the multimeter, set on current, and wires
> plugged to the "current holes" on the meter, into a power adapter,
> that shorts out the adapter, and potentially blows the protection
> fuse inside the multimeter, or the fuse inside the device being
> tortured.
Exactly what I have done! I heard a spark/click and wondered what I had
done, now the multimetre measures no current! Oops - it was only cheap!
Power supply seems fine and strangely, the laptop powers on today, but only
for a second. Will leave it to dry for another day!
Re: Tea + Dell 
Linear Mode
