HP Probook 470 G3 (Quanta X63C DAX63CMB6C0) - Not powering on with Adapter

Hello all

I have a HP Probook 470 G3 (Quanta X63C DAX63CMB6C0), it will power on fine and work with just the battery inserted, but if i try to power on with just the adapter alone or adapter and battery it will not power on at all. it does not charge the battery also.

Charging IC is BQ780S

When the power button is pressed the DC jack LED flashes orange 9 times and nothing else happens. I am not sure if this is somthing to do with the adapter ID signal.

Here are readings from the LIMIT_SIGNAL circuit for detecting genuine adapter. Readings are taken with a genuine HP charger both 45W and 90W.



Hope you can help, thanks.

Hello!

Measure the voltage to ground on resistor PR237 with connected power supply only (without battery).

Hi matic

Voltage on PR237 is 19V with just the adapter connected.

Measure the voltages to ground on pins 1, 2, 5 of chip PU3.
Measure the voltages to ground on pins 1, 2, 7 of chip PU21.
Measure the voltages to ground on coils PL11, PL29.

PU3, PU21 pin count (top view):

PU3
---
pin1= 3.2V
pin2= 0V
pin5= 3.3V

PU21
----
pin1= 3.2V
pin2= 0V
pin7= 5V
----
PL11= 3.3V
----
PL29= 5V

Measure the voltage to ground on pin 5 of charger chip PU14.

Pin 5 (ADP_DET) of PU14 is 0V

here are some other measurements from PU14

CMSRC pin 3 = 0V
ACDRV pin 4 = 0V
ACDET pin 6 = 2.7V
SRN pin 19 = 19.1V
REGN pin 24 = 6V
VCC pin 28 = 19.1V

KenM0560 napisał(a):here are some other measurements from PU14

CMSRC pin 3 = 0V
ACDRV pin 4 = 0V
ACDET pin 6 = 2.7V
SRN pin 19 = 19.1V
REGN pin 24 = 6V
VCC pin 28 = 19.1V

Some of that measurements seems wrong.
Please, remeasure the voltages to ground on pins 1, 3, 4, 5, 6, 20, 24, 25, 28 of charger chip PU14.

here are the measurements for PU14

pin 1 = 19.1V
pin 3 = 0V
pin 4 = 0V
pin 5 = 0V
pin 6 = 2.7V
pin 20 = 19.1V
pin 24 = 6V
pin 25 = 18.8V
pin 28 = 19.1V

With that measurements the transistor PQ26 is probably bad, and some other transistor as well.
Check transistors PQ21, PQ25, PQ26, PQ27.

They were checked onboard

PQ26
----
Red probe Source Black Probe Drain = .470
Black probe Source Red Probe Drain = OL

D =19V
S =0V
G =0V

PQ27
----
.549
OL

D =19V
S =0V
G =0V


PQ21
----
.507
OL

D =19.1V
S =19.1V
G =18.9V


PQ22
----
.177
OL

D =19.1V
S =0V
G =0V

PQ25
----
.507
OL

D =19.1V
S =19.1V
G =25.3V

The voltages on some transistors seems wrong, or you incorrectly identified these transistors.
Please, post a clear photo of these transistors on the board.

The transistors are identified correctly, but the voltage measurements seems wrong.

Correct voltages should be as follows:

PQ21:
D -> 19V
S -> Close to 0V
G -> 0V

PQ22:
D -> Close to 0V
S -> 0V
G -> 0V

PQ25:
D -> 19V
S -> Close to 0V
G -> 0V

PQ26:
D -> 19V
S -> 19V
G -> 25V

PQ27:
D -> 19V
S -> 19V
G -> 25V

All that transistors pin count: Pin 1= S, Pin 4= G, Pin 8= D
All voltages are specified with connected power supply only (without battery).

It is strange, i have checked them again but i still get the same readings. Could PU14 be defective?

PQ21:
D -> 19V
S -> 19V
G -> 18V

PQ22:
D -> 19V
S -> 0V
G -> 0V

PQ25:
D -> 19V
S -> 19V
G -> 25V

PQ26:
D -> 19V
S -> 0V
G -> 0V

PQ27:
D -> 19V
S -> 19V
G -> 25V

Some of your voltages are different now.

KenM0560 napisał(a):PQ26:
D -> 19V
S -> 0V
G -> 0V

PQ27:
D -> 19V
S -> 19V
G -> 25V

How you can explain that there are different voltages on S pins of transistors PQ26 and PQ27, while the S pins of both transistors are connected together on the board?
And the same thing with G pins of that transistors.

Sorry, my mistake. i typed the PQ27 readings incorrectly, they are still as of the first measurements

PQ27:
D -> 19V
S -> 0V
G -> 0V

Measure the resistance between pin 1 of PQ25 and pin 5 of PQ26.

resistance between pin1 of PQ25 and pin5 of PQ26 is 49k ohms

Remove transistor PQ25 from the board and remeasure the voltages to ground on all pins on place of PQ25.