A common problem with the PS4 is the BLOD (blue light of death).
There are many reasons for this.
The APU is one,it has 1000 odd solder balls underneath it connecting it to the motherboard. 1 or more of these balls are prone to crack and lose contact with the board. Reballing the APU is the way this is fixed.
The thermal image shows 1 of the RAM blocks towards the bottom right of the picture not starting up-(no heat)
They are reliant on communication with the APU,if one or more of the solder balls lose contact in the area causes this issue.
A reball fixed this console and bought it back to life