Hello everyone..
this board came with the symptoms of it turns on automatically then goes off, checked and found there was a little flood in the area of C302 witch was shorted, cleaned and restored and there is still an auto-start when charger is connected, all voltages rises and there is full initialization then it goes off, all in 5 seconds..
RTC checked and battery replaced, power button checked and there is 5v that goes to zero when pressed..
checked SYS_PWR_SW# signal and there was only 0.75v, resistance to ground at IT8502E pin 125 is 100 ohms
didn't find IT8502E in the donors so replaced with IT8512E, resistance at pin 125 became 90k ohms and voltage = 1v (there is a spike to 2.4v for half a second when connecting the charger then it drops to 1v) it goes to 0.2v when pressing the button...
removing the button has no change..
replaced the 100K pull-up resistor R301 twice, still 3.2v on side and 1v on the other
replaced everything at the power button (C386, R304, D30 & D31)
replaced 32khz W2 quartz
bios and ec flashed
still auto-starts with full initialize for 5 seconds then off, not wondering why with that 1v at SYS_PWR_SW#
at Q17, Q21, Q22, ACAV_IN & ALW_ON & 3.3V_ALW_ON all signals are there = 3.2v
at IT8512E all voltages are there (+RTC_CELL, +3.3V_RUN, +3.3V_ALW) = 3.2v
the resistance of +3.3V_SUS line is only 97 ohms, but the consumption is only 100mv@3.3v with the LBP and it rises to 3.2v normally...
at IT8512E pin 125 SYS_PWR_SW#, resistance to ground with removed R301 & D31 became mega ohms...
R301 to pin 125 continuity = 1.7 ohms
What kind of a ghost sits in there ??
