820-00165 no PP5V_S4RS3 and PP3V3_SUS

Narek

Member
I'm working on 820-00165 board, which came to me with description: "Turned off by itself, after a while turned on, but SSD wasn't detected. Now has no reaction for charger".

My observations:

- board is clean, no corrosion, no water damage, no mechanical damage.
- there is no green light when charger plugged in
- I have discovered, that PP3V42_G3H is missing and has low reading - 0,007V to ground in diode mode. After further inspection I found out, that short is caused by SMC itself. I have removed SMC and replaced it with one from the same board. PP3V42_G3H is back now, I have green then orange light on charger, but no fan spin.

Other measurements:

- PPBUS_G3H - 8,57V
- PP3V42_G3H - 3,42V
- PP3V3_S5 - 3,35V
- PP5V_S5 - 5,12V
- PPVRTC_G3H - 3,31V
- PP5V_S4RS3 - 0V (0,390V to ground)
- PP3V3_SUS - 0V (0,390V to ground)
-PP3V3_SUS_EN - 0V (0,495V to ground)
- PM_SLP_SUS_L - 0V (not pulsing)
- PM_SLP_S4_L - 0V (not pulsing)


I already have tried another SMC from 820-00165 board, but it behaves the same.
 

2informaticos

Administrator
Staff member
PCH must first release PM_SLP_SUS_L.
It expects PM_DSW_PWRGD, PCH_DSWVRMEN, SMC_ADAPTER_EN, PM_BATLOW_L and good RTC signals.
 

Narek

Member
These are reading for lines you mentioned:

PM_DSW_PWRGD is 3,42V
PCH_DSWVRMEN is 3,22V
SMC_ADAPTER_EN is 3,42V
PM_BATLOW_L is 3,22V

RTC signals:

PCH_CLK32K_RTCX is 0,441V
PCH_INTRUDER_L is 2,35V
PCH_INTVRMEN is 3,22V
PCH_SRTCRST_L is 3,3V
RTC_RESET_L is 3,3V
 

2informaticos

Administrator
Staff member
Looks like bad PCH.
It has all required signals, but doesn't want to release PM_SLP_SUS_L.
Maybe overvoltage on 3V42_G3H power rail affected PCH too.
 

Narek

Member
For me it sounds a bit strange, that it could kill PCH.. Is it worth to try changing bios? Or in this state it's pointless?
 

Narek

Member
Yes, I know that. Just thought, that my multimeter is too slow to catch short pulse on this line and bad bios cause PCH to cut it off.
 

2informaticos

Administrator
Staff member
BIOS chip (U6100) requires 3V power.
It doesn't play anything until 3V3_SUS appears...

Heat PCH with quality flux and pray.
 
Top