820-3024 PPVCORE_S0_AXG_REG missing

[Bouba148]

Hi team,

I have a 820-3024 that had a liquid damage but cleanned by someone else.
the board is turning ON, fan spin and getting faster and faster , maybe sense issue.

I have PVCORE_S0_CPU :1.159V and no PPVCORE_S0_AXG_REG:

at Q7550PVIN_S0_CPUAXG: 8.37V

at U7400
P5V_S0_CPUIMVP_VDD: 5.065V
CPUIMVP_VR_ON: 3.319V

CPUIMVP_BOOT1G: 4.791V
CPUIMVP_UGATE1G: 0V
CPUIMVP_PHASE1G: 0V
CPUIMVP_LGATE1G:0V

Resistance pin8/9: 56Ohms OK
CPUIMVP_IMAXB: 1.953V
R7440: 10 Ohms
R7423: 10 Ohms

by comparaison
CPUIMVP_IMAXA: 6.229V
CPUIMVP_IMAXA: 1.844V
CPUIMVP_PHASE1: 1.166V
CPUIMVP_LGATE1: 4.355V
CPUIMVP_IMAXA is 1.965V


R7467 and R7469 both removed and mesured around 80Kohms
Resistance to gnd at L7550/R7550 15 Ohms

Question: What is not present or peventing U7400 for not turning the AXG rail ON?

 

[JohnB8812]

What is the problem the board turning on or the sensors failing?? Run ASD and report any errors.

 

[Bouba148]

Hi , thanks for replying
​​​​​​
I've forgotten to say that it doesn't chime, doesn't boot, doesn't display , and also no backlight..
It's just fan spinning faster and faster.

 

[djdblaster]

I think PPVCORE_S0_AXG is present only when screen turns on / is detected?

 

[Bouba148]

Really ? Can someone please confirm.
​​​​​​Thanks

 

[Bouba148]

So i've replaced the Lio board and also tested with a good known screen but it's still the same

 

[2informaticos]

I know from 820-2936, for Sandy Bridge AXG CORE should be present from the begining; it appears with 0.9V but rapidly drop and stays at 0.45V.
Maybe not valid for al of them.

In case of 820-3115, with Ivy Bridge I saw many of them giving image on LCD without AXG VCORE.
You may see it for 2-3s with 1V and drops to 0V.

So I cannot confirm 100% for your board; supposed to be Sandy Bridge.
But if you can confirm USB activity, then probably AXG CORE stays at 0V until graphics load increases, like in Ivy Bridge models...

 

[Bouba148]

Hi Team,


I replaced the U6100 with a SOIC package one, because no WSON is stock, with a fresh clean dump: Turned it ON but had the same result, then I press power button before plugging the charger suddenly it chimed and booted correctly with image and backlight.

But I've noticed that the ON/OFF power button doesn't work: I can't turn it OFF whith long press on the Power button.
I did a PRAM reset successfully, but not sure for the SMC reset as the Power button doesn't react: so far Power button doesn't work.

Should I open a new topic for this?

 

[2informaticos]

Disconnect keyboard.
Use SMC_ON_OFF_L to see if turns on/off correctly...

 

[Bouba148]

Hi,
You can mark this thread as SOLVED,
Regarding the Power buton the pin 11 of J5700 was not soldered correctly, after soldering it was still NOK i followed the line to different points on the trackpad board, passed throught a 1 KOhms resistor to the keyboard connector on the ttrackpad board when pressing on the power button I had no feedboack to the ground directly at that point so I assume that it's a keyboard issue.

Thanks 2Informaticos for your help and support Muchas Gracias amigo