Dell Latitude 5520 Motherboard repair

[Cooped_Up]

So I have been working on this laptop for a while and I have come so far and I dont want to give up on it so I am hoping someone can see what I am missing. It started with "customer" my brother inlaws GF who said her laptop charger light blinked some colors at her and then no longer turned on so my Brother Inlaw looked at it for her and said there was nothing left to do. Me being me I said I would look at it. well that was close to 2 months ago and I have been working or waiting on parts lol. when my brother inlaw recieved it it no longer showed any signs of life it didnt do anything. my first check was an amp draw on the charger of which the dongle didnt even turn on with one C port and the other went to 5v low amps. So i looked at the charger ports conditions and decided to try swapping them which the problem didnt follow the ports still acted the same so I changed the PD controller which made it charge again yay but a multiphase voltage reg was getting hot so I replaced that. after that the keyboard lights up the bat indicator was telling me there was a prob;lem with the ram so I followed the power diagram and found boom the 2d5v reg was blown so I swapped that out and got 2.5v out. where I am right now is it turns the charger light white for a moment and turns off the keyboard stays lit and it cycles no display. I dont think I have Vcore. What am I missing is my multiphase controller bad or is my CPU maybe bad. Thanks for ay suggestions

[Cooped_Up]

As far as I can tell where I am with the motherboard state I make it to SIO slp3 and it is turning the VRM/multi phase controller on and it is outputing PCH PWROK but there is no power on the coils by the CPU. I have also tried injecting voltage onto the CPU on these coils to see if there was any hot spots and this didnt show anything, low currrent draw at .6v. This is why I think the CPU isnt shot yet. I think it is still repairable. I may be missing some details on what all I have done. I also checked the cmos bat and it was 3.05v. I can expound in more detail as to all of the going ons during the troubleshooting process but I figured a brief blurb would maybe be less confusing

[Cooped_Up]

I decided to put the original VRM back on the board and tried booting the computer and the cpu got hot fast as the vooltage at the coils was 1.7 volts, yikes. I am thinking maybe my replacement chips are fake and the original is bad so I dont know what to do about that

[FriedFred]

I think 1.7V for a mobile SoC is far too high. I would expect something between 0.65V and 1.2V at maximum. It's quite difficult to identify a dead-short on a CPU. But if the current consumption at 0.6V is still low, the SoC (and connected compoents in this area) might be okay.
I think, to judge the 1.7V whether this voltage is acceptable or not, you need to identify the used SoC and check it out for the used or recommended voltages.

[Cooped_Up]

In doing some more troubleshooting on the 1.7v Vcore I managed to make it stop working worse lol. so It is probably drawing closer to calling it quits. was adding resitors to the feedback on the VRM and got the vcore down to .4v but only momentarily. I am not sure which part of the equation isnt controlling the vcore voltage right but the VRM was regulating properly. i dont know if this means the cpu is faulty or what but I dont know what I would look at next I seem to have run out of options

[mcplslg123]

I think 1.7V for a mobile SoC is far too high. I would expect something between 0.65V and 1.2V at maximum. It's quite difficult to identify a dead-short on a CPU. But if the current consumption at 0.6V is still low, the SoC (and connected compoents in this area) might be okay.
I think, to judge the 1.7V whether this voltage is acceptable or not, you need to identify the used SoC and check it out for the used or recommended voltages.

1.7V as VCore is perfectly normal for 11th gen intel SOC.