00165 Weird CPU problem

[Rford]

Have a 00165 with some issue. The CPU is getting warm just like the other one I did but there is no short to ground betwixt VCORE and PPBUS_G3H

PPBUS_G3H-8.58V
PP3v42_G3H-3.43V
PP5V_S5 = 5V
PP3v3_S5 = 3.32
SMC_PM_G2_EN = 3.42
PPVRTC_G3H = 3.29
PP3v3_SUS = 0V
PM_DSW_PWRGD = 3.42
S5_PWRGD = 3.39
PPBUS_S5_HS_COMPUTING_ISNS = 8.58

PM_SLP_S4 = 0
PP3v3_s4 = 0
PP5v_s4 = 0

PPVCOMP_S0_CPU- 0
VCORE- 9.5 Ohm resistance to ground

CPU is warm? Wierd

S4s arent running... of course... Ideas??

 

[2informaticos]

Really strange thay CPU gets warm, when only 3V3_S5 is present.
Could be PCH issue, as you miss PM_SLP_SUS_L I suppose.
I can only think to VCCRTC issue of PCH.

Remove heatsink and tocuh PCH die (small one).
If that heats, most likely VCCRTC problem.
Check resistance to ground on it.

 

[Rford]

Indeed it is the PCH portion that is getting warm. Is there a separate VCCRTC? PPVRTC is 16K Ohms to Ground... VCCRTC is within and I cant test it... However ppvrtc connects directly to it.

 

[jadao]

Actually VCCRTC is the PCH labelling, You are in the RTC portion of the PCH and the name of the power rail going into VCCRTC is PPVRTC_G3H. Yep I had the same issue a few weeks ago on exactly the same board.

However, your resistance to ground on ppvrtc_g3h doesn't look like a short...
On my good bord I have 12kohms on the shorted one it's like 3ohms...

Let us know about :
PP3V3_SUS = 0V, Is it a short?
Do you have P3V3_SUS on U8020? You need both P3V3_SUS and PP3V3_S5 at U8020.
Are you missing (most likely) PM_SLP_SUS_L?

 

[2informaticos]

3V3_S5 also goes to PCH.
Don't waste time, if PCH heats without any other voltage than 3V42 and 3V3_S5, board is trash.
Not always short, or low value in a power rail point to a bad chip.
Even for high value there, one bad chip can go into some avalanche process when is powered up...