HP Victus Charging Circuit Issue – System Extremely Slow, No Charging

[adelfr2009]

Hi everyone, I’m working on an HP Victus 15 motherboard that previously had a strong short-circuit on 19v line. The laptop now powers on, but system performance is extremely slow and laptop works only on AC adapter
This are Important PIN Voltage Measurements (ISL88739 Charging IC)

1 ACIN 2.08V
2 ACOK 2.94V
3 SDA 3.28V
4 SCLK 3.28V
5 #PROCHOT 0v
10 COMP 0V
11 CCLIM 4.14V
12 FSET 0V
13 BATGONE 0V
16 ACLIM 2.48V
17 NTC 1.60V
18 DCIN 19.51V
20 VDDP 5.15V
21 LGATE 0V
22 PHASE 0V
23 UGATE 0V
24 BOOT 5.01V
25 BGATE 0V
26 VBAT 0V
27 OPCP 0V
28 OPCN 0V
29 CMSRC 19.77V
30 ASGATE 10.33V ( is this value Normal? )
31 CSIN 19.24V
32 CSIP 19.24V



I have 3 MOSFETs near the charger input: identical ones in parallel (likely AFETs). 1 different one (likely SFET)


I ovserved that The 2kΩ resistor between ASGATE and the MOSFET gate is heating (observed by thermal camera) . One side of this resistor = 10.3V (IC side)
➤ The other side (MOSFET gate) = 19.7V
➤ CMSRC is also 19.7V

Despite these abnormalities, the laptop still powers on from the charger, but extremely slowly.

Could one of the AFET MOSFETs have gate leakage causing ASGATE to stay stuck at 10V? Or the problem on ic charger or all is good and this is not the cause of the problems ?

[mon2]

Review the voltage divider resistors on pin #1. The voltage here is too low. It should be 2v4 or higher. Be sure the power adapter is the original one and proper power rankings (watts) else a voltage drop can cause these events.

[adelfr2009]

Review the voltage divider resistors on pin #1. The voltage here is too low. It should be 2v4 or higher. Be sure the power adapter is the original one and proper power rankings (watts) else a voltage drop can cause these events.

I already tested with another original charger, same wattage. ACIN = 2.08V on my board and 2.10V on a working Victus, so it’s very close to the reference and ACOK is high.
I don’t think the adapter or ACIN divider is the issue.

[mon2]

PROCHOT# indicator for system low voltage, adapter
overcurrent, battery overcurrent, or system overheating

This is an active low signal and is 0V on your board. This means the adapter voltage is being deemed by the charger IC to be too low. Review the referenced 2 resistors and adjust to raise this threshold voltage. Ideally should be 2v4.

[adelfr2009]

Thanks, I will check the ACIN divider as you suggested. But I still don’t understand how an ACIN issue could explain the 10 V on ASGATE and the heating on the 2 kΩ gate-resistor (similar laptop have this value= 24v !!! ) and is normal that the gate of the mosfet = 19.77v!

[adelfr2009]

This is an active low signal and is 0V on your board. This means the adapter voltage is being deemed by the charger IC to be too low. Review the referenced 2 resistors and adjust to raise this threshold voltage. Ideally should be 2v4.

Thanks, I will check the ACIN divider as you suggested. But I still don’t understand how an ACIN issue could explain the 10 V on ASGATE and the heating on the 2 kΩ gate-resistor (similar laptop have this value= 24v !!! ) and is normal that the gate of the mosfet = 19.77v!

[mon2]

A low driving gate voltage is text book case documented by piernov (see above charger sticky thread). This often implies that the dcin MOSFETs are defective. Remove all power. Meter in resistance mode.

Measure :

Source / drain
Source / gate
Gate / drain

Post each measurement. The dcin MOSFETs are suspects due to the low gate voltage. As a quick test, remove the gate resistor and test if the gate voltage boosts to around 25v at the charger asgate pin.

Asgate voltage = adapter voltage + reg
= 19v + 5-6v = 24-25v to drive n-channel MOSFETs.