I replaced the battery and the motherboard on my Nexus-6, it does not work

[etofach]

My Nexus-6 was suddenly dead, no display, no charging
When I press simultaneously the POWER-off button and the Lower-volume button, the nexus shake for a second.
I replaced the battery and the motherboard on my Nexus-6.
The parts were removed from another Nexus -6 with a broken screen, in the broken Nexus: the battery was able to be charged and a real display was seen over the broken screen glass.
After installing the (used and working) motherboard and the battery in the dead Nexus, still its dead/
Now when I press the POWER-off button a the nexus shake for a second, thats all , No display
Any advice? thanks

 

[N4Newbie]

My wife's out-of-warranty Nexus 5X began doing the exact same thing one day a few months ago. Thankfully, Google replaced it for free.

Beyond that, I have no real advice to offer. The physical power button is on the motherboard, correct?

Maybe the problem is in one of the daughter boards causing a boot failure early in the process... Why not just replace them all?