Asus x541u vcc core missing

[arber1232]

Hello everybody . I have an Asus laptop that turns on but does not display the screen. I continued with the voltage measurement.19 v is ok 3.3v is ok 1.5 volts in RAm is ok. but in cpu I do not have 1.0v or 1.2v ... how much can the processor have. And the processor was cold ,, .. After some measurements I noticed that PQl8104 was short. I removed it and replaced it with mosfet 6414A I do not know if it is a choice but please tell me .. I put it in the charger I see that the cpu is hot but there is no image. I did the bios that I found in this forum but again the same problem After the voltages in Pl8102 it is 0v and in Pl801 it is 0 v..This laptop has NCP81216A chip. Please tell me what I can do to diagnose the problem. Thank you This is board view ....And the FAn not spining . I try to turn of laptop but turn on agin for 2 sec.

[emestee]

Re: Asus x541u vcc core missing

Re-test all secondary power rails for short to ground and short to B+. Remove the CPU and power up the board, test voltages and watch for the board turning off.

[arber1232]

Re: Asus x541u vcc core missing

I not understan B+ can me explain ?.. And i not cant remove cpu becouse is soldered in board......... measure in ohm these two points minus the camera in the gnd of the laptop and + in PL801 and pl802

[emestee]

Re: Asus x541u vcc core missing

B+ is the main 19v rail.

0.3 ohm is a short. This plus CPU heating up is not good news. Interrupt the VCORE power line as close to the CPU as you can and measure the voltage on it. If the voltage is normal after you replaced the mosfet, and the mosfet you replaced was the high side switch, then there is a good chance the 19v went straight into the CPU and you now have a donor board...

[arber1232]

Re: Asus x541u vcc core missing

the mosfet is ok ... i close line in pl801 and pl802 but the cpu is hott . and voltage is 0.2 v in mosfett

[emestee]

Re: Asus x541u vcc core missing

This means there's a short in the CPU and its pulling down the voltage, which is why you should test it by interrupting the VCORE line to verify it. Pull out the coil or some other component in the path to the CPU to verify. However, it does appear that your CPU is dead...

[arber1232]

Re: Asus x541u vcc core missing

ok i understand you maybe my cpu is dead . but i not understand when i closed lin in pl801 and pl802 why not have voltage in mosfet ?

[emestee]

Re: Asus x541u vcc core missing

I dont know what PL801/802 do. I cant open boardview because im at work.

What do you mean you "closed" the line? The 0v you're seeing is because the short on the CPU sends the voltage to the ground. This is why I am telling you you need to _disconnect_ the CPU to verify that the voltage goes back to normal when the CPU is disconnected.

ok i understand you maybe my cpu is dead . but i not understand when i closed lin in pl801 and pl802 why not have voltage in mosfet ?

[arber1232]

Re: Asus x541u vcc core missing

ok pl801 and 802 are behind the mosfet that supply the processor with voltage. that should give 1.5 volts or less .. when I disconnect these I have no voltage. yes it is logical not to give because the cpu is in shorttt ... In processor i have 1.0 v coming from 2 points pjp 8104 and 8303. when I disconnect these laptops it turns on for a while and turns off .. now I have left only pjp 8303 connected and the cpu heats up a bit. pjp 8104 connect +vccsa and +vcccio_cpu pjp8303 connect +1.0vo and +1.0vsus

[arber1232]

Re: Asus x541u vcc core missing

I dont know what PL801/802 do. I cant open boardview because im at work.

What do you mean you "closed" the line? The 0v you're seeing is because the short on the CPU sends the voltage to the ground. This is why I am telling you you need to _disconnect_ the CPU to verify that the voltage goes back to normal when the CPU is disconnected.

i mean i cut line

[emestee]

Re: Asus x541u vcc core missing

ok pl801 and 802 are behind the mosfet that supply the processor with voltage. that should give 1.5 volts or less .. when I disconnect these I have no voltage. yes it is logical not to give because the cpu is in shorttt ... In processor i have 1.0 v coming from 2 points pjp 8104 and 8303. when I disconnect these laptops it turns on for a while and turns off .. now I have left only pjp 8303 connected and the cpu heats up a bit. pjp 8104 connect +vccsa and +vcccio_cpu pjp8303 connect +1.0vo and +1.0vsus

If that's the case, I'd put an oscilloscope probe on mosfet gates. If nothing's there, then check enable signals on the DC-DC converter that feeds it, then the converter itself

[arber1232]

Re: Asus x541u vcc core missing

The Dc is ok I have 19v in mosfets

[emestee]

Re: Asus x541u vcc core missing

The Dc is ok I have 19v in mosfets

No, I am asking about the gate control

[arber1232]

Re: Asus x541u vcc core missing

the gate control not have voltage is 0v .

[mcplslg123]

Re: Asus x541u vcc core missing

0.3Ohms on cpu line may not be short as cpu is soldered. +1.8V is present?? Check all pwrgood signals.

[arber1232]

Re: Asus x541u vcc core missing

pwgrd in ncpe is present is 3.3 v .. Which +1.8 v ?
where i find +1.8
please can you explain to me a little deeper where i can see all pwrgd and +1.8 v

[piernov]

Re: Asus x541u vcc core missing

CPU VCore should be around 6 ohms to ground.

[arber1232]

Re: Asus x541u vcc core missing

CPU VCore should be around 6 ohms to ground.

IN pl8102 i have 13.6 ohm to ground in pl8101 o have 0.13 ohm this point ore cpu vvcc core ?

[piernov]

Re: Asus x541u vcc core missing

PL8101 is iGPU VCore but it should be around the same value than CPU VCore.

[arber1232]

Re: Asus x541u vcc core missing

then I have gpu in short