Drive's firmware contain tables that are written there during the manufacturing, with calibration data and other pointers that relate to the exact those platters that are in this specific hard disk.
Replacing PCB with a different one, even same model, would either not work at all, or not work reliably. You need to copy that data from old PCB to the new one. If the PCB on the old drive is completely dead, and this data is important to you (read: worth more than several thousand dollars), I think you should turn to professional data recovery services.
Firmware is unique to the PCB this controls calibration and track
information so it is very rare to be able to interchange the same
model PCB with one that has another firmware revision... so what this
means, if your board shorts out the firmware unique to the drive, you
will be in trouble. Of course a good main stream data recovery company
will be able to replace this and manually reprogram this chip