No image on 820-4924

[Fizzl92]

This 820-4924 was dropped. Now it shows nothing on the internal screen. On a external monitor it works normally and also recognizes the internal screen. If i look closely i can see that the LCD backlight is activating in the moment as the keyboard backlight turns on (same second the apple logo finishes loading on the external monitor) I can also close it and open it back up and the backlight tuens right back on. I can also turn LCD backlight brightnes up and down manually in the OS. I tried 2 other LCDs (not new ones - i took them a while ago from dead devices but at least one of them should show any reaction i think) and i get the same issue on both. I measured 5.11V on L8300. Now i am stuck.

 

[dukefawks]

So you have backlight and just a black image? Check diode mode on C8320-29 on pin 1.

 

[Fizzl92]

Thank you. Diode mode readings:

c8320 = 0.279V
c8321 = 0.280V
c8322 = 0.282V
c8323 = 0.282V
c8324 = 0.284V
c8325 = 0.282V
c8326 = 0.282V
c8327 = 0.285V
c8328 = 0.282V
c8329 = 0.283V

 

[dukefawks]

That is fine. Is there continuity from pin 2 of all those caps to the end of a separate LCD cable?

 

[Fizzl92]

Yes it is. It beeps and the reading is always <10 Ohms

 

[dukefawks]

Then there should just be an image. There could be board damage under the CPU still of course. Was the original LCD cracked or just no image after the drop?

 

[Fizzl92]

No it was not cracked. It was just no image...

 

[dukefawks]

My bet is on cracked traces under the CPU then. Just to make sure SMC_LID is high? If so then this board is probably not fixable.