Alien M17 notebook does not respond to repair when it is turned on

Alien M17 notebook does not respond to repair when it is turned on

The external resistance of pin 5 CS2 of the control chip TPS51225 of 3VALW is changed to 10K, but the fault wave pattern remains unchanged. After replacement, power-on test is conducted, and the machine is normally turned on for display, troubleshooting and perfect repair.

Machine model: Alien M17 notebook

Main board number: LA-F552

Malfunction: The laptop doesn’t respond when it is turned on.

Maintenance process:

An alien M17 notebook didn’t respond when it was disconnected by pressing the switch. Repeatedly pressing the switch found that the current of the power meter flashed from 0.01 to 0.02 and then fell back to 0.01. At the beginning, it was determined that the fault was power-on interruption.

Under standby test, 3VALW(PL101) and 5VALW(PL102) are generated normally, and standby is normal.

Test voltage 3V is normal, test RSMRST# sent by EC with oscilloscope, and then fall back to low. SLP_S3# and SLP_S5# have the same action, and the power-on is normal.

The fact that RSMRST# is low basically means that the basic conditions of EC are lost. For example, the external protection circuit pulls down the ECRST#, or the external circuit turns off the EC power supply, and the EC power supply is abnormal when tested. The EC power supply is shown in the following figure:

Alien M17 notebook does not respond to startup and maintenance Figure 1

After the switch is pressed, the EC power supply drops obviously, and the lowest point is more than 2V. At this time, the EC power supply voltage is lower than the normal operating range of EC, so the EC stops working. Power-on is stopped, and then the voltage is restored to 3.3V Power-on again, and the fault is the same as before.

After S3 is raised, the voltage of 3VALW drops, and after S3 is closed, the voltage recovers. This kind of fault mostly comes from +3VS abnormality. It is found that +3VS is not short-circuited.

Change the external resistance of CS2 on the 5th pin of the control chip TPS51225 of 3VALW to 10K, and press the switch to power up, only the inductance of 3VALW will click, but the fault wave pattern remains unchanged.

Alien M17 notebook does not respond to startup and maintenance Figure 2

Measured 3V conversion level 2, when U16 is measured, a fault is found. The schematic diagram is as follows:

Alien M17 notebook does not respond to startup and maintenance Figure 3

Measured +3VS_ssd short circuit.

Alien M17 notebook does not respond to startup and maintenance Figure 4

After replacement, power-on test is conducted, and the machine is normally turned on for display, troubleshooting and perfect repair.

Alien M17 notebook does not respond to startup and maintenance Figure 5