HP Pavilion 17-f255nb - DAY22AMB6E0 - no power

[johnbeton]

Hello,

I have a Pavilion 17-f255nb, no power led and not turning on.
I have 19v up to the second mosfet PQ17, but on pin 1 and 3 of PQ17 I only have 1v.
Also no 3v, 3.3v, 5v, ...
I have the schematics and boardview in attachment, Any ideas what I have to check ?

[MOD EDIT] Link to schematic/boardview - https://www.badcaps.net/forum/showthread.php?t=125849

Thanks in advance.

[Techtiger]

Re: HP Pavilion 17-f255nb - DAY22AMB6E0 - no power

Which supply do I need for BQ24728H pins 20, 5, 4, 16, and 6? PQ12 S D G voltage ?

[johnbeton]

Re: HP Pavilion 17-f255nb - DAY22AMB6E0 - no power

This is the result:

BQ24728H:
pin 20 = 19.6v
pin 5 = 2,97v
pin 4 = 0,88v
pin 16 = 6,04v
pin 6 = 2,73v

PQ12:
S = 19,64v
D = 19,72v
G = 18,12v

[mon2]

Re: HP Pavilion 17-f255nb - DAY22AMB6E0 - no power

BQ24728H:
pin 4 = 0,88v

ACDRV should be ~25 volts = adapter voltage + REGN voltage = ~25 volts.

Do review the above sticky on chargers by @Piernov.

Likely mosfet @ PQ17 is defective. Remove all power.

Meter in resistance mode. Measure the resistance across this (or any suspected) mosfet to confirm if leaky or not.

source & drain
source & gate
gate & drain

Post each measurement. No power during these tests (reminder).

[Techtiger]

Re: HP Pavilion 17-f255nb - DAY22AMB6E0 - no power

issues with the PQ12 component and suspect that there may be a problem with the voltage supply to S (Drop)pins 1, 2, and 3. Additionally, suspect that there may be a problem with either PQ12, PQ14, or one of the voltage dividers connected to PQ14, as the gate supply is high. To troubleshoot this issue, recommend testing PQ12 with a multimeter in Diode mode without power and checking PQ14 voltage on all pins. This should help identify any faulty components or voltage supply issues that may be causing the problem

[johnbeton]

Re: HP Pavilion 17-f255nb - DAY22AMB6E0 - no power

PQ17 seems to be fine, I have exact new ones and compared and replaced with no result.

These are the voltages on PQ14:
Pin1 = 19,15v
Pin2 = 19,15v
Pin3 = 18,11v
Pin4 = 19,64v
Pin5 = 18,69v
Pin6 = 19,08v

I tested PQ12 in diode mode -> black probe on source - red probe on drain = 0,6kOhm
Other combinations have no continuity.

[johnbeton]

Re: HP Pavilion 17-f255nb - DAY22AMB6E0 - no power

I removed PQ17 and injected voltage to pin3, then the charging light worked.
I then jumped a wire from pin 4 to 3. Now the systems starts fine.
But still confused to where the source of this problem lays.

[mcplslg123]

Re: HP Pavilion 17-f255nb - DAY22AMB6E0 - no power

PQ14,pin3 is the problem area.