Post a clear closeup pic of the component side of the pcb. The TVS diodes will be two small black rectangular components with one solder pad point on each end in the area right behind the power connector. PCB swaps on this family often require relocating or reprogramming the ROM chip due to information stored on the board that is particvular to that specific drive. The information from another drive usually is not compatible.
On Seagate's the TVS diodes are oftent hte problem. If there is no visible damage ( cracking/scorching etc on the diodes, then you must check the with a multimeter set on diode test position. A good TVS will show short (tone) in one direction adn open ( no tone ) in the other. If it reads short in both directions then the component is blown. Once you identify the daaged component the simplest solution is to remove the the diode by unsoldering it from the board. This will allow the drive to spin up and initialize. The drive should only be run in this condition on a known good power supply because you have effectively removed the over-voltage protection. Another over voltage condition will destroy more sensitive components. The disk should be replaced after recovering your data. You can replace the TVS diodes with comaprable diodes to continue running the drive, but I would still not trust it to critical data, and make sure I had good recgular backups of the data on this disk.