Sometimes the boards corrode with time, in other occasions falls break the boards and create microscopic gaps; these things disrupt communications within the board. If this was the problem, all you have to do is check for continuity.
A blueprint is useful for this matter, but you could trace the threads of the chip without one. Just check the board from the back, not the front.
This is a common problem in circuit boards; regarding micro-soldering, the common practice is not transplanting the chip, but bridging the faulty terminals to their destinations using wires (at least for the first attempt to repair the board).
You can check this generic video on continuity.