820-3588 not turning on.

[donnos]

PLT_RESET_L is 0v
same goes for the RAM, tried each slot and swap them with known good.
also flash with good bios same.

 

[2informaticos]

You must get PLT_RESET_L high.
Seems that power on sequence is not completed.
Post U8600/1 voltages.

 

[donnos]

U8600 all pins 3.3V except ground. same goes for U8601

 

[2informaticos]

So, both PM_PCH_PWROK and PM_PCH_SYS_PWROK are high.
What about PM_MEM_PWRGD?

 

[donnos]

PM_MEM_PWRGD is 0.8v

edit
PPVCCIO_S0_CPU and CPU_VIDSCLK is also 0v

 

[donnos]

so follow this chart for power up sequence https://logi.wiki/index.php/Bootup_Signal_Order i'm getting stuck at CPU VR Ready that's why i'm missing LPC_PWRDWN_L. but i can't find CPU_VR_READY in the schematics.

 

[2informaticos]

It is REG_CPUVCC_PGOOD (VR_RDY).
Should be high, as you get CPU core.

Check =PM_PGOOD_MEM_S0.

 

[donnos]

so.. weird thing happened, system was running, fan spinning, as soon as i put my probe on R8430, it shuts down and reboot. this is repeatable, and no i did not short something out.

i leave my probe on the point, system starts up. shows me 3v3v. remove and probe again, shuts down

 

[2informaticos]

Does the board boot in such condition?
Check for USB activity, or external video, if the board is alone on the desk.

 

[donnos]

Sorry, system running as in I only have led0302 still no gpu good. And no cpu activity

 

[2informaticos]

Yeah, difficult to understand a post, when is written in such manner.
I now suppose that you've meant to say the board reboots when you touch PM_PGOOD_FET_P1V35_S0 line with multimeter probe.

Has R8430 correct 22K value?
Do you get PVDDQ_S0_FET?

 

[donnos]

R8430 has 22k

i'm getting 1.34V on PVDDQ_S0_FET.
the board reboots not only when i touch PM_PGOOD_FET_P1V35_S0 line, it also happens when i touch R8535 pin2/PM_EN_REG_CPUVCC_S0 side as well

 

[2informaticos]

I supposed you get REG_CPUVCC_PGOOD, but not sure now; you've said didn't find VR_READY.

 

[donnos]

Yes i do get REG_CPUVCC_PGOOD, yeah earlier i said i didn't know where on it on schematic. and i have 3.3v on this line

 

[2informaticos]

You cannot get away, without PLT_RESET_L.
Seems that PCH doesn't properly detect that power on sequence finished.

The new PCH may be bad, or broken traces/solders underneath.
Could also be a CPU problem, less probably.

 

[donnos]

Replaced another PCH. i have good news! i have PLT_RESET_L and my CPU Vcore is 1.76V
CPU Heats up so i know its running.
BUT! i now do not have GPU_GOOD. no chime no display no light on LED0303.
only lights on at LED0302 and LED0301
Sorry man this is taking so long. i appreciate your assistance here

 

[2informaticos]

Did you flash BIOS again?

 

[donnos]

yes, i did flash again but still getting the same outcome.