Hi,
I have HP DV4, motherboard: JAL50 / Compal LA-4102P. I got it with the diagnostics "do not charge battery" after receiving the unit I found it does not switch on at all. No current consumption was shown on my LAB psu on charger connector. Firstly replaced PQ101 - it was shorted. Now consumption is about 20mA and 3,3V and 5V is present. After connecting the battery power LED on the Mb switch on for about 2seconds, then some clicking sound from the MB and everything goes to reset and all starts again. No real voltage is shown on the battery terminals, also removed battery charging FET-s PQ110 and PQ108 - the clicking sound remained. More - during the clicking sound basically all the voltages drop a bit (3,3V,5V,19,5V). During the period when the battery is connected and the LED is on it is possible to switch on the MB, for 1-2sec or so. Other times the power switch do nothing.

The clicking sound seems to be some kind of short somewhere that "kills" some power rail that is switched on. I am thinking of the charging controller: BQ2474

PS! I do not have the correct charger at the moment (with the center Id pin) but this should not affect the MB that way or..?

Charger ID pin is necessary, basic knowledge. Place 100-200K resistor from ID pin to +19V to make it work.
Should really post this in beginner section.