Dear friends,

I would like to help me solving the problem i have.
My favorite laptop Acer aspire 5942g motherboard is totaly destroyed from my bad luck attempt to reflow the BGA chip. So the original m/b is off now.
Fortunately, i had bought another m/b with some problems and i decided to give a second chance.
The new m/b has the problem that with no RAM, no CPU placed and giving power 19VDC, it lights the 3 blue lights. Then, when i pressed the POWER button, it goes on for 3-5 sec and then goes off.
I 've found broken parts which i' ve replaced (PU7), a FET and a transistor, and then i clean the m/b well and put fresh thermopaste above the 3 main chips (CPU, BGA, VGA). I've measure +5VALW, +3VALW. After then, when i press the power button, it goes on and i have image through VGA cable.
I connect then the HDD and it goes into windows. I was very glad but unfortunately, the laptop goes off after 5 minutes.
I did that many times and the laptop goes off even into welcome screen BIOS settings after 5 minutes no matter what.
Flash the BIOS with version 1.05, no luck.
I took off the RAM, the CPU and starting measures. So far i have:
No pressed power button:
+3VALW, +5VALW, +0.9V to PL11. Total current is about 200mA
After press the Power button:
+3VALW, +5VALW, +1.5V, +1.8V +1.1V (no battery connected). Total current starts from 200mA and goes up to 2.3A. Screen in VGA monitor is OK.

A strange measure i get is the VGA_ON signal that has 3.3V without pressing the power button. Is that normal?
Also, i get +1.0V to PL7 which is strange too.
Looking the schematic, i noticed than the signal DGPU_PWR_EN is pressent with +3.3V. Is that normal too? What conditions must have to get this signal corectly?

I would apreciate any help.
PS. A good boardview file would be very helpfull to find points for measuring.

Hello. Yes, DGPU_PWR_EN 3.3v is normal, similarly on PL7, 1.0v is normal
Does the laptop always turn off after an equal amount of time? What is the temperature of the GPU and CPU?

the consumption is too much before powers on
While the laptop is up and running, have you checked all peripherals? Where did you take the bios dump to flash?

If I were you, I'd buy or borrow an infrared imager and check the m/b for too hot elements, then replace them.
200 mA in stand-by mode is really too much, it should be about 10-15 mA.