Alien M17 laptop does not respond when it is turned onrepair

Alien M17 laptop does not respond when it is turned onrepair

Machine model: alien M17 notebook

Board number: LA-F552
Malfunction: The laptop computer doesn’t respond when turned on.

Maintenance process:
For an alien M17 notebook, pressing Switch for disassembly didn’t respond. Pressing Switch repeatedly found that the current of the power meter quickly 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 the standby test, 3VALW(PL101) and 5VALW(PL102) are generated normally, and the standby is normal. Test that Switch VCC 3V is normal. Test that RSM RSMRST# sent by EC rises instantly with oscilloscope, and then falls back to low. SLP_S3# and SLP_S5# have the same action, and power-on is normal.
Rsrst # is low, which is basically the loss of basic conditions of EC. For example, the external Current protection circuit pulls down ECRST#, or the external circuit turns off EC VCC, and the test of EC VCC shows an abnormality, which is EC VCC.

Alien M17 laptop does not respond when it is turned onrepair Figure 1.
After pressing Switch, EC VCC dropped significantly, and the lowest point reached more than 2V. At this time, EC stopped working because the EC power VCC was lower than the normal working range of EC. Power-on was stopped, and then VCC returned to 3.3V and powered on again, and the fault remained. After S3 is raised, 3VALW VCC falls down, and after S3 is closed,VCC recovers, which mostly comes from +3VS anomaly. The measured +3VS is not Short circuit.Change the 5th pin s2 external Connect the power supply resistor of 3VALW’s control chip TPS51225 to 10K, press Switch to power on, and only listen to 3VALW Inductor”click” sound, but the fault wave pattern still hasn’t changed.

Alien M17 laptop does not respond when it is turned onrepair Figure 2.
Measured 3V conversion level 2, when U16 is detected, the fault is found,schematic.

Alien M17 laptop does not respond when it is turned onrepair Figure 3.
Physical map.

Alien M17 laptop does not respond when it is turned onrepair Figure 4.
Measured+3vs _ ssd Short circuit.

Alien M17 laptop does not respond when it is turned onrepair Figure 5.
Power-on test after replacement, normal startup display of the machine, troubleshooting and perfect repair.