a2289 820-01987 was very slow now won't boot.

Bravo2001

Member
Hi, got here a new problem case. Received it with only little info. little corrosion around u7000 Fixed it easy. Was booting fine but very slow hihg CPU usage while Idle. Checked all set sensors nothing missing or no high temps. After another cleaning with flux around the u7000. Now won't boot. I checked all the power rails.

USB-C amp 20v up to 0,4a than steady 0,05a
All there even
ALL_SYS_PWRGD 1,8 v after 10 sec back to 0v
PM_PCH_SYS_PWROK

But no
PPVCC_S0_CPU 0v

Checked for corrosion around u7220 and u7210. looks clean.

What can It be?
 

2informaticos

Administrator
Staff member
If all components in place, something reacted to heat applied.
Board had some problem already, if was slow.
 

Bravo2001

Member
I think it has to be something to do with origin of the problem, system being slow and now there is no PPVCC_S0_CPU... Maybe we can troubleshoot back.

Where does PPVCC_S0_cpu come from? U7220 and U7210. Both are supplied with PPBUS_HS_CPU
What is needed for u7220/u7210 to create PPVCC_S0_cpu??

Could it be that only 1 Phase se was supplied before and that was the reason of the slow cpu? Not enough power? I can't find much about this subs that's whyI'm thinking out of the box...

This in advance
 

2informaticos

Administrator
Staff member
PCH/CPU and T2/BIOS are involved to generate CPU core voltage.
Is not just a simple enable signal...

Could you complete DFU restore?
 

Bravo2001

Member
No, DFU restore gave error… Can a bios Cause no CPU Core voltage? I read a lot about bios disruption. I‘ll try to reflash bios.
 

2informaticos

Administrator
Staff member
You can't flash BIOS; is secured into T2.
SoC ROM (U4770) is not BIOS, but sometime can prevent the board to work correctly; give it a try.
 
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