No ppvcore_gpu - Starts and chimes but no Display of course

I really did mess up my board, after i removed the gpu to check for shorts i powered on the board without gpu and blowed C8942.

Then i reballed the GPU replaced C8942.

Checked the powerrails and found:

missing ppvcore_GPU and GPU_REG (PPVIN_S5_HS_GPU_ISNS is present) and Q8950 was getting real hot, so i replaced it.

At this point my fans started to spin again and i got astartup chime but

still no Display.

Then measured GFXVIMVP6_UGATE on Q8950 - not present but on U8900.

So i connected it directly with a wire and then Q8950 started to get hot again.

I've got no idea where my short is - think ppvcore_gpu is shorted.

U8900 seems to be fine, since in and outs are present, but still im not shure.

GFXIMVP6_UGATE (pin 18 on U8900) gives me 158 kohm to ground

thanks for help or any ideas

P.S. can i use an other ISL for example a 9504 instead of the 6263?

Update (21.07.2018)

How does Q8950 work? Where does UGATE come from?

If R8940 is removed Q8950 isnt geting hot, but still no voltage on UGAT or pin 18.

L8920 gets 12 volts, PPVCORE_GPU_REG_R is 12 volts, isnt that to much? how comes?

Answer this question I have this problem too

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Comments:

If you aren't a professional, then you shouldn't perform low-level service on a logic board.

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It's my own Board, so its no service.

Nevertheles ur coment is really unneceseray and 0 help, i think this site is here for supporting people, if u have the knowledge and don't bother them and waste their time.

so i guess u got no plan how to help me, right?

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