Acer 5741z motherboard problem!?

[MitProject]

Hello everyone! Today is my first day in forum! I have a problem with my laptop Acer 5741z. Working normally, but the time came for the prevention of cooling. I do this many times, not only on this laptop. Disassembled the computer, cleaned it, but once you put together does not start. I guess I made a short circuit on the motherboard. What I did so far is as follows. I tested the charger jack. Operate normally. I tested power button board and work fine.
Please direct me to where I can look for problems. I noticed that when i put the power in motherboard chipset starts to heat. And this happens without I start the computer, only put the charger. Motherboard model is la-5892p. Sorry for bad english!
Thanks to all!
Regards

 

[armapker]

have you gone a full loop around all the connectors, making sure they are all firmly plugged in?

 

[jarotech]

Hi, what you should do is disassemble to the bare motherboard and plug it to see if you still have the problem. When you disassemble, look at anything who could short circuit the motherboard.

 

[MitProject]

I try to start only bare motherboard! CPU and RAM and cooler are plugged in. Nothing else! Any ideas?!

 

[jarotech]

What chips are overheating ?

 

[MitProject]

Chipset!

 

[jarotech]

Everything is connected to this chip (U4). Any component could short circuit to the chip.

 

[MitProject]

Yes! But how to find fault?

 

[jarotech]

To find the problem, you must have at least a voltmeter and a soldering iron.

 

[MitProject]

Yes! I test many elements on motherboard using voltmeter but i cant find problem!

 

[jarotech]

You should have +5V on U25 at pins 5-6-7-8 and 1-2-3. +3V on U26 pins 5-6-7-8 and 1-2-3. +1.5V on U24 5-6-7-8 and 1-2-3.