820-2915 no power fan spin 3 secondes and stop loop

[aurel476]

Before replacing gpu i've heated gpu and board starts ok

After replacing gpu twice, same probem, fan spin 3second and stop loop

Good light, orange light ok

Glue under vram removed before and checked balls after

Garbage gpu?

No composant missing or burned

PPVIN_S5_HS_GPU_ISNS 12.56V

Another point to check?

 

[aurel476]

Ppvcore_s0_cpu 0v (short to gnd) :/

gpu vcore up to 1v about and 0 when fan stop

SMC_CPU_HI_ISENSE 0.8V

ALL_SYS_PWRGD up to 3v about (too fast for read next)

 

[dukefawks]

1) Where did you get the GPU and which date code?
2) You can remove the GPU, these boards will boot up without one, there will of course be no image.

 

[aurel476]

date code 1532 garbage ^^ ?

What are the good date code for you ?

I will try without gpu if board start

 

[aurel476]

find cracked ball under vram reflowed and Without GPU same problem,

 

[dukefawks]

No idea, any component you damaged may cause this. Heated CPU too much?? I have no idea.

 

[aurel476]

cpu not too heated because for test i've reflow gpu first same temperature before replace, and cover CPU with adhesive high temp,

Balls touch under vram can cause this ?

 

[aurel476]

tried without vram same problem cpu dead for you ? what check

 

[dukefawks]

Pretty sure you killed the CPU.

 

[premtec]

Ppvcore_s0_cpu always 0V?
You can try to pass with your soldering iron some leaded solder at the pins of U7400

 

[dukefawks]

Ppvcore_s0_cpu always 0V?
You can try to pass with your soldering iron some leaded solder at the pins of U7400

Why would you do that? Makes no sense that would be an issue after GPU replacement. CPU need to talk to U7400 to enable it, CPU is dead so no Vcore.

 

[premtec]

and how CPU died after GPU replacement?

 

[aurel476]

Ppvcore_s0_cpu always 0V?
You can try to pass with your soldering iron some leaded solder at the pins of U7400

Always 0V PPVCORE_s0_cpu, U7400 fine

i've probably fried CPU because GPU is proximity (overheat)