Dell Vostro 270 Inspiron 660 Motherboard 0478VN 11061-1 DIB75R 478VN

[captainKKK]

I have tried every trick in the book to get ANY response out of this motherboard. Known good PS, CPU, and DDR3. No response with push of the power switch...nada, nothing. All peripherals, removed exc kybd, mouse, and VGA. Jumped the power supply at the plug and the cpu fan runs at high speed, but there is no post and no sounds... Magnified inspection of components reveals no physical damage nor evident heat markings. Ideas?

[piernov]

Make sure you have a compatible CPU in the socket and that the CMOS battery is ok (>3V). Yes both those can prevent a motherboard from turning on with some specific models.
You tried shorting the pins of the motherboard for power switch manually? Do you have 3.3V on those pins?

[captainKKK]

I know the power switch is good, and I tried running a screw driver over the exposed start pins. I had another good MB that started and ran without a battery in it, but this one did not. I have not tried a new battery......I will check for voltage on the power pins. I found several places on the board where the mosfets had 3 to 12 volts and the fuses I tested are good. I took the good running CPU and memory out of the good MB and put in the bad board and nothing changed. The CPU and memory from the dead MB runs fine in the Good MB... I even reflowed the Southbridge and no change. Thanks for the reply