This is a post on the (seemingly) same problem that has gotten a lot of attention here recently (you might want to focus on final/3rd paragraph – “bending”):
I had a FP3 which also from one moment the other went OFF and i was not able to turn it ON again.
The Battery was charged and the USB port cleaned - dissassembled all and cleaned all connections - but nothing helped.
As i had a lot of Fotos and Data on the phone which i did not have backedup yet - i wanted to find a solution.
So i took apart the FP3 and studied the marks on the chips of the mainboard and found by searching the ICs in the web that a defective Qualcom Power Managment Chip PMI63…