ASUS N56VM Laptop water damage Won't Turn On Repair

ASUS N56VM Laptop water damage Won’t Turn On Repair

Machine Model: ASUS N56V

Board number: N56VM_2.3

Chipset: HM76+NV independent display

ASUS N56VM Laptop water damage Won’t Turn On Repair Figure 1.

Fault phenomenon: laptop water damage Won’t Turn On, with standby no power on,no power on has entered the water

Maintenance process: The dismantling found that it had been repaired by the previous home.

ASUS N56VM Laptop water damage Won’t Turn On Repair Figure 2.

ASUS N56VM Laptop water damage Won’t Turn On Repair Figure 3.

ASUS N56VM Laptop water damage Won’t Turn On Repair Figure 4.

I cleaned the standby chip and checked the location where the previous home was moved, and found that the public point was abnormal.

ASUS N56VM Laptop water damage Won’t Turn On Repair Figure 5.

This machine isolates two N-channel drivers of Current protection and is turned on. Under normal circumstances, the G level is 25V. The problem of the isolation tube was eliminated, and the 6 pin ACDET of the charging chip BQ24725A was found to be abnormal when the gun head was turned around.

ASUS N56VM Laptop water damage Won’t Turn On Repair Figure 6.

Through Boardview query, ACDET is divided by 127K resistor and 20K resistor, 20V input normal value should be 2.7V. The online measurement of the diode value is normal. After heating the PCB layer, the VCC recovers to 2.7. Don’t think about the PCB layer problem, just change it directly.

ASUS N56VM Laptop water damage Won’t Turn On Repair Figure 7.

Cut off the chip 6 pin PAD, separate Jump wire out to the voltage divider,VCC has recovered to 2.7V and stabilized, and the isolation tube G-level VCC is also normally boosted to 25V.

ASUS N56VM Laptop water damage Won’t Turn On Repair Figure 8.

Power on again, the common point is successfully generated, still no power on, standby 0.07.

ASUS N56VM Laptop water damage Won’t Turn On Repair Figure 9.

I touched the standby chip high temperature by hand, and the power-off measurement linear PWM post-stage did not have Short circuit. Considering that the standby chip had water damage before, it was suspected that the chip itself was damaged, so I replaced it directly and powered it on again. The machine can display normally.