Acer Nitro 5 AN515-57, GH51G LA-181P Rev: 1B not booting.

[MicroSMD Lab]

Good day, I need some assistance with this laptop. It came in with no power after a liquid spill. The device was very dusty and one of the inrush mosfets exploded, the other was shorted and of course a shorted 19V power rail. I replaced the following defective components to clear the short:
PQB4 (AON7380, this one blew up, pads needed to be rebuilt, no vias)
PQB3 (EMP21N03HC, this one was shorted)
PQB1 (L2N7002WT1G, burnt and cracked)
PUV2 (QD9619AQR1, shorted)
After replacing these components and checking to make sure there were no shorts, the laptop powered on for 8 seconds, the fans spun twice then the laptop powered off. I am using known-good RAM. The CPU heats up when it attemps to power on, CPU resistance on the coils is around 27 ohms. The CPU core voltage is 1.8V which I think is too high.
At this point I'm hoping the CPU is still good and maybe it's a bios issue. TIA for your assistance.

[mcplslg123]

Core voltage for 10/11th gen cpu at 1.8V is ok and not too high.

Is the 19V rail shorted again?

[MicroSMD Lab]

19V rail is good. If I press the power button another time, keyboard backlight comes on, fan spins once then it powers down again. Appreciate the quick response, thanks

[mcplslg123]

Yes, I too feel cpu is still good to go-so worth investing time as this is expensive mb.

What are the voltage on coils for the brief time it turns on. You may need to switch it multiple times to measure all the coils.

[MicroSMD Lab]

These are the voltages:



PLB2 - 0.216V (no batt)______PL1801 - 1.9V_______ PLW1 - 1.2V

PLM1 - 1.2V________________PLV4 - 0.8V_________PLH2 - 1.8V

PL501 - 5V (AlwaysON)______PLV3 - 0.8V_________PLH3 - 1.8V

PL302 - 3.39V______________PLV2 - 0.8V_________PLH4 - 1.8V

PL1102 - 1.8V______________PLH14 - 0.8V________PLG101 - 1.8V


I noticed that I didn't solder PLV2 after raising it to locate the shorted DrMos. After switching on multiple times to take the voltage readings, the fans spin and stop 3 times, I put the board back in the housing and it booted. I suspect that because I didn't fasten the heat sink all the way, it shut off due to high temperatures or the missing GPU voltage.
Thanks again for your help.

[mcplslg123]

Nice to know its fixed but a word of advice-Never try to turn on a gaming mb without heatsink,it"ll never boot and shutdown.

[MicroSMD Lab]

Thanks, for the benefit of others, I did put on the heatsink but only fastened 3 screws lightly. From now on I will fasten all properly before testing.