Asus BX325J UX325/425JA - Martwy, brak ładowania

Płyta: UX325/425JA rev 2.1
APU: SRG0N
KBC: IT5571VG-128

Płyta nosiła ślady korozji w okolicach chargera (PU1 = BQ25700A) - uszkodzony PR18, PC33 i uszkodzona ścieżka. Elementy wymieniłem, ścieżkę naprawiłem. Poprzedni właściciel twierdził, że laptop działał do rozładowania baterii, ale nie jestem w stanie tego zweryfikować (bateria 0V).


Po podłączeniu zasilacz USB C przełącza się na 20V, nie ładuje baterii, płyta nie startuje, brak poboru prądu. Sytuacja taka sama na obu gniazdach USBC.

Pomiary (Zasilacz podłączony do USBC#1 (JTB1) ) :

+VBUS_TYPEC_P1 = 20V (Mierzone na CT57)
+VADP = 0V
+V5P0A_TYPEC_P0 = 0V


PU1:
pin1 (P_CHG_ACP) = 0V
pin2( P_CHG_ACN) = 0V
pin7 (+VDDA) = 0V

Proszę o pomoc w zdiagnozowaniu usterki. Mam niewielkie doświadczenie z płytami zasilanymi z USBC.

Hello!

Measure the following voltages to ground with the power supply connected to the port JTBT1:
- On pin 1 of capacitor CT53.
- On pin 1 of transistor QT13.
- On pin 3 of transistor QT4.

CT53 = 3.48V
QT13:
pin1 = 0V
pin2 = 0V
pin3 = 0V
QT4:
pin1 = 3.47V
pin2 = 0V
pin3 = 0V

Pin order according to boardview

Perform the following measurements with the power supply connected to the port JTBT1:
- Measure the voltage to ground on pin 1 of transistor QT5.
- Measure the voltage to ground on pin 5 of chip PU3001.

QT5 pin1 = 0V

My board is a little bit different than boardview. PU3001 in boardview is SY8288BRAC QFN chip, on my board it is LE=7H ( RT6258BGQUF ? UQFN-12HL)
By asking for pin5 of PU3001 you mean +VSYS ?
PU3001 pin5 (+VSYS) = 0V






Im using this boardview: schemat-asus-zenbook-13-ux325-ux325ea-14-ux425-ux425ea-nb2555-t68787.html?hilit=UX325

- Measure the resistance directly on capacitor PCAP1.
- Measure the voltage directly on capacitor CT60 with the power supply connected to the port JTBT1.

PCAP1 = 60 Ohm
CT60 = 19.99V

poster napisał(a):PCAP1 = 60 Ohm

This resistance is too low.
Perform a short circuit test described here on the capacitor PCAP1. For a short circuit test limit the voltage to 20V.

Edit:
Before performing a shot circuit test also measure the resistance to ground directly on capacitor PCS3001. If the resistance is high (in kΩ range or greater), perform a short circuit test as suggested.

PCS3001 = 320kOhm


I've performed a short circuit test, UT6 (KTS1677EVH) was getting hot. I've removed it from the board. Resistance on capacitor PCAP1 = 1.3 MOhm now.

Is it safe to connect power supply to JTB2 now?

poster napisał(a):Is it safe to connect power supply to JTB2 now?

Yes, it is.

After connecting Power supply to JTB2 board doesnt power on.
CT91 pin1 = 19.99V (+VBUS_TYPEC_P1)
PCAP1 pin1 = 0V (+VADP)

Should i replace both: UT6 ad UT9 to continue repair of this board?

Measure the voltage to ground on pin 1 of resistors RT162, RT166 with the power supply connected to the port JTBT2.

RT166:
1 = 0,07V
2 = 3,47V

RT162: both pins 0V

Both chips - UT6 and UT9 seems damaged. Replace both.

After replacing UT6 and UT9 (KTS1677EVH) board works fine. It took over a week to get them from mouser.com .
Thank You!