Grey screen after apple chime.

Hi, my Macbook get a grey screen after chim .

Its happens after i did a upper case swap ( my case was bent). Macbook has no spills or any problems before.

I dont have a mini DP cable to test a video output.

I did memory swap with another Mac- but no luck.

Any suggestions?

Thank you!

I tried to reset SMC and PRAM- no luck

Also tried to boor in safe mode- same grey screen.

I did a upper case with keyboard because my case was bent.

Macbook boots up and i can adjust brightness of the screen and sound volume

but its only no image on the screen.

Thanks

mayer, sorry about that my bad

ordered a mini display port cable to check on the external monitor.

No image on external moniror as well :(

I decide to sell it for parts , but nobody want it

Next step is reballing a gpu Nvidia on logic board