w355stq

[highpulse]

hi guys , here we are again after sometime of disapearance ,

got here clevo w355st one of many we got here to fix , this machine was with short on 3VA line , analising hm87 was in short in the 3.3volts line . so replaced it , and short is gone , the machine turned on , took some second to give image and entered the bios , shut it down , added the hdd to try it on windows , machine turn on , no image..
started cheking things again , Vcore on cpu is at astonishing 1.78 volts .. damm thats not good , cheked things around NCP ,all seem ok , cpu replaced same issue , ncp replaced same issue , sense resistors all ok , temp resistors ok ...

my question is , problem wich PCH could originate such high voltage on the cpu core ? (pch is another i had on another clevo board)
but it did worked on biggining .. here it is schematic

[ktmmotocross]

Re: w355stq

v core is just another step-down circuit. if u have bad voltage u have something bad in that circiut.

[piernov]

Re: w355stq

I'm not sure about this but I think on Haswell CPUs the VCore buck controller is actually controlled by the CPU itself to give the proper VCore. So if the CPU doesn't work/doesn't turn on, it cannot regulate its VCore correctly.

[dycc]

Re: w355stq

hi guys , here we are again after sometime of disapearance ,

got here clevo w355st one of many we got here to fix , this machine was with short on 3VA line , analising hm87 was in short in the 3.3volts line . so replaced it , and short is gone , the machine turned on , took some second to give image and entered the bios , shut it down , added the hdd to try it on windows , machine turn on , no image..
started cheking things again , Vcore on cpu is at astonishing 1.78 volts .. damm thats not good , cheked things around NCP ,all seem ok , cpu replaced same issue , ncp replaced same issue , sense resistors all ok , temp resistors ok ...

my question is , problem wich PCH could originate such high voltage on the cpu core ? (pch is another i had on another clevo board)
but it did worked on biggining .. here it is schematic

i know that lynx point pch have processor of 4th generation and the voltage is correct

[dycc]

Re: w355stq

also high impedance compare to other generation . 1.6~1.7 v to operate

[dycc]

Re: w355stq

I'm not sure about this but I think on Haswell CPUs the VCore buck controller is actually controlled by the CPU itself to give the proper VCore. So if the CPU doesn't work/doesn't turn on, it cannot regulate its VCore correctly.

begining from the first to the 6th VCore is controlled by the CPU itself ( vid ,svid).