Thinkbook 15 G2 ITL no ALW voltages after replace burned USB-C contoller

[ktmmotocross]

Hello.
Have this Thinkbook 15 G2 ITL that have burned USB-C controller U24. After replace i have main VIN voltage, but no ALW voltage. PU301 have VIN but no LDO and other voltages. i relace ic but still the same.
ic is SY8386. LDO should be working right after vin ?

board code is LA-K052P

any hint?

[mcplslg123]

Logically yes but as long as there is no shorted/leaky component on LDO rail.
What is the resistance to GND on LDO pin?

[ktmmotocross]

Logically yes but as long as there is no shorted/leaky component on LDO rail.
What is the resistance to GND on LDO pin?

no shorts on LDO or other rails

[mon2]

What is the exact resistance measurement to ground?

Remove all power. Meter in DIODE mode. Red meter probe to ground. Black meter to the LDO rail that is without power. What is the exact measurement?

[khaahk]

From the schematics of K051 (hopefully similar) PU301 LDO output has enable pin. It gets a value from resistor voltage divider, might be worth checking out.

[mon2]

Good point khaahk

Was this controller replaced with 100% of the same type? The suffix of the part # are important.

Review the voltage to ground of EN2 pin # 8 = enable for the LDO rail.

[ktmmotocross]

Good point khaahk

Was this controller replaced with 100% of the same type? The suffix of the part # are important.

Review the voltage to ground of EN2 pin # 8 = enable for the LDO rail.

no signal to EN1 or EN2

[mon2]

Review the resistors that build up the enable line trigger for this LDO.

Do you have the main voltage rail arriving at resistor @ PR508?