820-00426 no video

[Kyle93]

Has no liquid damage. No video on internal or external. Using known good internal LCD.Turns on and chimes but no video.

L9410 and L9330 0v

SMC_Lid 3.2v

what to check next?

 

[2informaticos]

Check GPU power up sequence, page 68.

 

[Kyle93]

EG_RAIL1_EN and P0V95R1V8GPU_R_EN 0v

Bad smc???

 

[Kyle93]

solved r8292 was missing

 

[Kyle93]

This is having a issue to where it won’t boot from usb install or internet recovery. A little over 1/2 way progress bar fans spin really fast screen goes dark. Have to hold power button to turn off and when turned back on same cycle repeats. Is this a FDM608 issue?

 

[2informaticos]

Could be GPU issue.
Try Linux, or Windows Live USB.

 

[Kyle93]

boots from mac os external drive no problem

 

[2informaticos]

Then try fresh install...

 

[Kyle93]

It will only boot from external drive with OS already installed. When trying to boot from usb installer the screen goes black about 1/2 way through after fans spin real fast. Same goes for a internal SSD with fresh install from another system

 

[2informaticos]

If you can enter macOS through USB, then try GPU stress test, like Unigine Heaven.