HP 15 ac102la dead no power

[eseunico]

No power. Disk not spinning. Charging led won't turn on. Tried with and without battery.

Motherboard is abq52-la-c811p. 19.5 v on the power jack red wires, 0.7 on brown and 0 on all the others.

0v on PQB1 and PQB2 and 0 on PRB1. I think it is a short to ground, but cannot test further on live voltage as the motherboard has started to spark around the capacitors near the mosfets above.

I need to replace the mosfets, caps and resistors near tehm too as I fear they are damaged from the sparking, but where else should I test to find the short? Does anyone understand the power architecture and can they explain it to me?

Attached is schematic of motherboard.

[mon2]

Re: HP 15 ac102la dead no power

hi.

1) remove all power to the logic board.

2) meter in resistance mode.

3) measure & post the resistance for the following:

a) PQB1: drain (pin 5-6-7-8) & source (1-2-3)

b) PQB1: drain (5-6-7-8) & gate (4)

c) PQB1: source (1-2-3) & gate (4)

d) PQB2: source (1-2-3) & drain (5-6-7-8)

e) PQB2: source (1-2-3) & gate (4)

f) PQB2: gate(4) & drain (5-6-7-8)

[eseunico]

Re: HP 15 ac102la dead no power

Resistance values are inconsistent. Tried with two different multimeters. The source gate resistance for both mosfets starts at around 14k and afterwards keeps climbing up, while the source drain and gate drain starts at 88k and keeps climbing up for both as well. They take very long to settle and settle at different values, but all the values are at the 10k-210k

[mon2]

Re: HP 15 ac102la dead no power

So the mosfets do not appear to be shorted.

If you apply the power adapter, are you able to take voltage measurements?

Concerned about the sparks noted in your post. What caused the sparks?

1) voltage @ PDB1, pin 2? pin 3 ? pin 1 ? The voltage @ pin 1 will be used to power the charger IC @ PUB1.

2) voltage @ ACDRV_CHG_R ?

3) sheet 4 / 52 of the schematic offers the power rail sequencing for this logic board. Follow these in order (from the top) to see which rail is not working and post your results here.

[eseunico]

Re: HP 15 ac102la dead no power

Ugh, cannot find pdb1 in this mess. I am new to this, where is it exactly?

[eseunico]

Re: HP 15 ac102la dead no power

Covered in flux from a previous repair, I think? Cannot contact client now to be sure, but where else would the flux come from?

I think PRB5 is the one I highlighted in yellow as it has 10 ohm resistance and continuity with PUB1, but where is PBD1?

[mcplslg123]

Re: HP 15 ac102la dead no power

There is a current sense resistor just after the 2 dc-in mosfets(maybe rated R010). What is the resistance to GND on this resistor?? It seems you have short in +19V rail.