Hi motheboard MSI Z270-A-PRO the cpu LED is on ( the pins are straight ) . Motheboard turn on no memory , cpu voltage. All resistances are good , on pch 40ohms. I found boot sequences to this motheboard. The post stops at SYS_PWROK , the second PCH_PWROK its no present. So i think bridge is died .

pch_clk актуален после PCH_PWROK

я бы начал с проверки VPP

On VPP 5V but 0V pw good 7-legs MP2147

this pwm is dead. change it.
it must be 2.5V with pwm signal, but not 5V constantly.

Ok replace MP2147 now have 2,5V pwm and power on cpu and memory. But 0V on VCCGT . I found that 1 phase vccgt control rt3606 and another rt9624.

We do not need vccgt yet.
look at the oscilloscope exchange on the BIOS, 5 pins. if there are pulses, flash it with the programmer.

On 5 legs i have puls signal . Flash bios but still turn on cpu diode on motheboard.

CPU-PWRGD only 0,9V its normall value ??