Need help diagnosing the NM-D471 REV 2.0 motherboard for a LENOVO laptop.

[JJ8409]

Hello,
I need your help with an issue I'm encountering while diagnosing a NM-D471 REV 2.0 motherboard from a Lenovo laptop. The laptop won’t power on. I started by checking the power rails, including the main power line and the 3.3V and 5V rails.

I do have a proper 3.3V across the line, including at the chip responsible for managing 3.3V/5V—same goes for the 5V rail. I haven’t tried to simulate a power-on yet, since the main issue still needs to be resolved.

I have full access to the boardview, but I’m not sure what to check next to isolate the problem.
However, I believe I’ve detected a short circuit on the PWR_CPU_PWR decoupling line, particularly starting from capacitor PC1026 (which appears to be a polarized capacitor, please correct me if I’m wrong). The two other nearby capacitors on the same line also seem to be shorted.

I have already removed those components from the board, but the short circuit still remains.
Do you have any idea what could be causing this, or suggestions on how to trace the faulty component?

[Bonzas]

Hello,
I need your help with an issue I'm encountering while diagnosing a NM-D471 REV 2.0 motherboard from a Lenovo laptop. The laptop won’t power on. I started by checking the power rails, including the main power line and the 3.3V and 5V rails.

I do have a proper 3.3V across the line, including at the chip responsible for managing 3.3V/5V—same goes for the 5V rail. I haven’t tried to simulate a power-on yet, since the main issue still needs to be resolved.

I have full access to the boardview, but I’m not sure what to check next to isolate the problem.
However, I believe I’ve detected a short circuit on the PWR_CPU_PWR decoupling line, particularly starting from capacitor PC1026 (which appears to be a polarized capacitor, please correct me if I’m wrong). The two other nearby capacitors on the same line also seem to be shorted.

I have already removed those components from the board, but the short circuit still remains.
Do you have any idea what could be causing this, or suggestions on how to trace the faulty component?

how do you know those line is shorted ? because have low resistance ? how much resistance you get there ?

[JJ8409]

Starting from the polarized capacitor PC1026, in continuity mode I get a beep on each pad as well as on all components along the line.
In resistance mode, I measure 0.23 ohms across capacitor PC1026.

[Bonzas]

so, you already measure other voltage that missing from the board right ?
You have short on 19v line or no ? if no short on 19v, 5v, 3v line. I think you can measure what voltage that missing on your board before judge the cpu line shorted.