ASUS Vivobook M7600R (M6500RC R2.0) - 19V Power Rail Not generated, AC-Detect

Without resistor A:

transistor C:
1= 0V
4= 0V
5= 20V

transistor D:
1= 0V
4= 0V
5= 1.5V

Are the transistors C, D the same (marking 32320C)?
Are they original, or maybe they were soldered before by someone else?

No, i did replace one of them at the start of the job. I replaced with one from a DC-IN section from another board. They both measured ok, and were working when using a USB-C adapter, the laptop charged the battery and powered on.

I will measure them again.
C:
S-D = 3.4M ohms
S-G = 51k ohms
D-G = 3.6M ohms

D:
S-D = 5.6M ohms
S-G = 0.4 ohms !!!
D-G = 5.5M ohms

Would the 0.4 ohms reading for transistor D (S-G) be because of Resistor A being off the board?

KenM0560 написав:No, i did replace one of them at the start of the job.

Please, post a clear picture with visible markings on the old (original) transistor.

KenM0560 написав:Would the 0.4 ohms reading for transistor D (S-G) be because of Resistor A being off the board?

Not at all.
Remove this transistor and measure it out of the board, but it's damaged almost for sure.

matic написав:Please, post a clear picture with visible markings on the old (original) transistor.

Unfortunately i can not find the original transistor that i replaced.

matic написав:Not at all. Remove this transistor and measure it out of the board, but it's damaged almost for sure.

Measuring the transistor off board it was measuring ok, between S - G was around 2M ohms. I am not sure why it measured short when on board, after putting the transistor back on the board, S - G is now measuring 51k ohms.

KenM0560 написав:Unfortunately i can not find the original transistor that i replaced.

If so, please post a picture of another original transistor that is still soldered to the board.

The markings of an original transistor are "G4 UUC 3Y0203"

KenM0560 написав:Both of the gates connect to the bottom of the resistor in the second picture
[ Obrazek ]
[ Obrazek ]

Are the gates connected to any component other than the resistor on the bottom side and capacitor, resistor on the top side (located between both transistors)?

I couldn't find anything else, i had a good look around in continuity mode, all around that area and on the underside of the board.

Try to replace both transistors with the P-channel ones (for example: AON6403, AON6407, AON6411, PK5B9BA, ...) and remeasure the voltages to ground on pins 1, 4, 5 of both transistors.

Hi matic

Unfortunately the customer needed the laptop back and was happy to use it with a USB-C adapter instead.

Thank you for your time trying to figure it out, it is much appreciated.