3DS XL 2015 Won't turn on.

Hi guys,

I'm from germany so please forgive my bad english :)

My 3DSXL 2015 just don't want to start.

I've had the issiue with the poping sound. The blue LED lighted up but the booth screens was still black.

So I bought a 3DS with a broken screen and switched the parts with my broken 3DS.

I switched out the motherboard, Top Screen, Bootom screen, Speakers and the camera.

But it is still broken and won't tun on. Popoing sound and the screens remain black.

The broken DS was working so was could it be guys, any idea?