Lenovo L15 Gen2 Not Booting

[chick0n]

My L15 doesnt power on. When I connect charger, charging light lights up, and Power LED blinks 3 times, then nothing... When I press power button nothing... I tried everything, remove batteries, checking fuses...

Maybe BIOS is corrupt?

Mainboard is: NM-D271 HL4A0 / HL5A0 REV2.0

[chick0n]

Bios dump

[Vesko356]

Bios dump

Do not post a bios dump in this section please.

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[chick0n]

sorry

[mon2]

Carefully measure the voltage to ground of each pin on dual dcin mosfet at PQ0204. Post each measurement. Schematics are available in the schematics forum.

[chick0n]

Pin1 0V
Pin2 0.443V
Pin3 0V
Pin4 0V

[mon2]

You do not have the power coming from the external power adapter (based on the measurement on pin # 2 of this dual mosfet).

Carefully measure the voltage to ground at both sides of the fuse @ F6001.

[chick0n]

I testet without poweradapter, just with batterie. I will test again tomorrow, with adapter.

[chick0n]

Now measured with batterie and power adapter (batterie is charging)

Pin1 16.26V
Pin2 20V
Pin3 0V
Pin4 1.767V

When I connect the power adapter, the power led blinks three times. When i press power button, nothing happens.
When I disconnect cmos batterie and connect power adapter the power led stays on, fan spins up, cpu gets warm, but no picture. sometimes I even get a error code over speakers.

[mon2]

Connect the power adapter. What is the voltage to ground at capacitor c6002?

what is the voltage at the fuse f6001?

[chick0n]

c6002 20V
f6001 0V (Fuse is good)

[chick0n]

It works:
https://www.badcaps.net/forum/troubl...n2-not-booting

SD-Card Controller was burned, and BIOS was Corrupt.