I have been struggling to repair a HP 8460P laptop. Motherboard does not turn on. I have traced the problem to what seems to be a missing signal KBC_PWR_ON causing Trip2 on IC 5006 (TPS51123) to be activated.
The following components have been replaced but the problem remains.
C5191
C5192
U50006
Listed below are voltages appearing on U5006 when the Motherboard is supplied with power from a bench power supply for the first 15 seconds or so.
Pin 1 (Trip1) = 0.65
Pin 6 (Trip2) = 0.65
Pin 8 (Vreg3) = 3.31
Pin...