[Moved] Laptop motherboard short circuit?

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nadabro

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Hi.

I was using my laptop normally and suddenly it goes off..after that no light in the laptop with adapter or battery (tested with two batteries).

When i plug the ac adapter in the Laptop the LED of the ac adapter gets blinking with a on/off buzzing sound...so it looks like a short circuit in the laptop motherboard, right?

I´ve noticed that when i connect the AC adapter, one component in the board gets really really hot (only after 2/3seconds)..this is a image of the motherboard (red circle really hot)


**broken link removed**


Tested the voltage in the ac adapter, board pins and cable, everything looks ok.

Is there anything i can do to resolve this issue? Its doesnt have warranty..

Thanks

High resolution images:
front
**broken link removed**

back
**broken link removed**
 

Re: Laptop motherboard short circuit?

30V P-Channel PowerTrench MOSFET

Tj = –55 to +175C

Can You describe "really really hot" ? Is there smoke? Did you measure temp ?

FDD6685 datasheet link :
https://www.fairchildsemi.com/ds/FD/FDD6685.pdf

Rather pay attention on left upper MOSFET you see aligment ? All other parts is placed by machine precizely on their places. Maybe that MOSFET overheat earlier and melt solder paste.
 
Last edited:

Re: Laptop motherboard short circuit?

Thanks for replaying.

I did not measure the temperature, but sure its >60º..enough to burn my finger if i keep it there more than a few seconds. Thats the only component that gets hot, the others are cold. After a few seconds it starts to smell overheated plastic..


About the aligment on the upper left MOSFET, i did noticed that, but it looks still in good contact..should i give a bit of solder just in case?
 

tpetar said:
Maybe upper left MOSFET gone and left this one below alone to work. :wink:
Click to expand...

Those MOSFET are pretty easy to find, i can replace both.

If that is the problem, maybe i can recover the board? Or maybe it damaged something else?

I´m getting a little hope here :grin:
 

first you have to remove both mosfets and check for shortage and leakage with your digital MM and also give me the motherboard model no. i can help you.
- - - Updated - - -

Remove mosfets(PQ31, PQ32)
 

Hi,
whats the model of the pc ?
You can look on PL11 (if is right -on the left of the socket) PL14 ,PL15 if you detect shortage .
Yes ,like above , PQ32 is some how weird .
 

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