Asus A550V notebook does not trigger repair

Asus A550V notebook does not trigger repair.

Machine model: ASUS A550V

Main board version number: X550CC 2.0

Fault phenomenon: the notebook does not trigger, and there is no standby current.

Asus A550V notebook does not trigger maintenance Figure 1

Take apart the computer and take out the motherboard, and observe that the charging chip, EC, BIOS and standby chip on the motherboard have traces of welding, but no other abnormalities are found.

There is no obvious short circuit in the common points, 3V5V, memory, bridge, graphics card and CPU on the main board. Connect the power supply to 0.005A, and press the switch to trigger it. This unstable fault needs more tests.

Plug and turn on the machine repeatedly there, and finally the current becomes 0.000A again. At this time, the voltage at the common point is only 0.9V, which is obviously a problem on the charging chip side. I changed so much at home, and measured the working conditions of the chip.

Asus A550V notebook does not trigger maintenance Figure 2

The 20-pin VCC and 6-pin ACDET are all normal, so why not output high level? Poor protective isolation tube will also cause the chip not to output a high level of 24V, so it will be replaced decisively.