laptop motherboard : short circuited DC input

[itt788]

I have a laptop motherboard which suddenly had its DC input ends short
circuited. It workded normally for hours and switched off normally. When
trying to run it again some day after it won't boot up and I noticed that
the DC input ends were short circuited.

[Jeff Liebermann]

Look for a big reverse power protection diode across the DC input
connector. Also, if your battery charger is of the "universal"
variety, look for the power being applied backwards.

If that's not it, I suggest you disclose the maker and model number,
and if it works on battery power.

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

[M Philbrook]

In article <55abe0f8$0$3017$426a...@news.free.fr>, itt...@outlook.com
says...

Plugged the wrong adapter into it?

Do you have others in the place that also likes
to plug things into stuff like that?

It just sounds to sneaky..

Jamie

[itt788]

I wrote a bit too fast my message and I skipped some important
information.

When I tried to boot up the computer and noticed it won't do I first
checked the transformer and it showed the right voltage on the voltmeter
screen. I also tried to draw some power using a fixed resistor which
value was chosen to get something around 1 A and indeed the expected
current values flowed within the resistor.

Then when trying to plug back it into the computer I noticed a big spark
everytime I was trying to plug it in. That's when I noticed with an
ohmmeter that the DC input ends were short-circuited. I also tested the
battery, the voltmeter show a nice 0 Volt for each cell while it should
fully charged.

I disassembled the computer and noticed that the short-circuit was caused
by a MOSFET next to the DC input socket on the motherboard but after I
replaced it, this new component also got killed and shorted the DC input
ends.