Please check the resistance between PQ2 (pins 5-8) and ground. If the resistance is too low (about few Ohms), it means the short-circuit in the main of power branch. If the resistance is OK, then PQ2 may be damaged or, You must check the voltages on PU2 (BQ24751).
You can do the simple test - set the current limiter in laboratory power supply unit to 200mA (voltage to 19V) and connect the power supply unit, then short-circuit the drain and source of PQ2. If the current limiter gone latched (current value over 200mA), then You will know You have a short-circuit in the main of power branch.
I this case pay attention to PQ6 - PUMB2, double transistors in very small 6-pin case(very diffficult to find on the mainboard). This is Foxconn-specific schematic, and to find a replacement for this element is very difficult. It is getting broken quite often.