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

Measure the voltages to ground on pins 14, 15 of charger chip.

Voltage to ground of charger chip
14 = 1.5v
15 = 1.5v

Resistance to ground for pin 14 and 15 is 133k ohms

KenM0560 написав:[ Obrazek ]

Please, also post a picture of another side of the board.

When using a USB-C adapter the 19v line does come up, and the battery starts to charge. But still same symptoms with regular adapter.

Measure the voltage to ground on any pin of the current sense resistor you marked in the picture with a regular adapter connected.

KenM0560 написав:[ Obrazek ]

With the regular adapter connected both sides measure 1.5V

Please, post a clear picture of marked area of the board.

No problem, here is the area. Both of the gates connect to the bottom of the resistor in the second picture, and the chip to the left has 1.8v on pin 3 and 5, and 0v on the rest.

KenM0560 написав:[ Obrazek ]

Measure the voltages to ground on all pins of 5-pin chip marked "SCG" visible in the picture.

The chip marked SCG starting from bottom right pin in orientation of the picture (could not see dot to mark pin1 on the chip)

1= 1.47V
2= 0V
3= 1.7V
4= 1.8V
5= 3.3V

KenM0560 написав:could not see dot to mark pin1 on the chip

This chip is in a classic SOT323-5 (also known as SOT353) package with a standard pinout (picture below), so you counted the pins correctly.


Measure the values of resistors "A" and "B" marked in the following picture. Both resistors must be removed from the board to measure their actual value.

matic написав:so you counted the pins correctly.

At least my memory is still holding up lol.

Off board
Resistor A = 600k ohms
Resistor B = 470k ohms

There is around 50k ohms fluctuation either way when measuring.

KenM0560 написав:There is around 50k ohms fluctuation either way when measuring.

Test your meter with a known good resistor with the resistance around 470k-1MΩ.
If you have the fluctuation as well, try to replace the batteries in your meter.

Also post a picture of this area of the board with resistors A, B and chips marked "SCG" and another marked "8KB" near it removed form the board (I want to see the path of the copper traces under these components).

After changing the battery in the multi meter, i am now getting a more steady reading of

Resistor A = 1M ohm
Resistor B = 700k ohms

No problem, here is the area without Resistor A,B and ICs SCG and 8KB on board.

Use a continuity tester and check, if the left pin of resistor "A" is connected to the ground.

Yes it is connected to ground.

Solder all components back to the board, except the resistor A and measure the following voltages to ground:
- On pins 1, 3, 4, 5 of chip marked "SCG".
- On pins 1, 2, 3, 4, 6 of chip marked "8KB".

All components are back on board apart from Resistor A.

SCG
---
1= 1.4V
3= 1.7V
4= 3.1V
5= 3.3V

8KB
---
1= 0V
2= 3.1V
3= 0V
4= 0V
6= 0V

Measure the voltages to ground on pins 1, 4, 5 of transistors "C", "D" under the same conditions (without the resistor A).