1. is it possible to just change the PCB board and recover files from my hard drive?
For now we can say in 99% of cases it's not possible, you also have to change BIOS ROM Chip, or rewrite the ROM Firmware from the original PCB to the new one.
2. is it possible to do data recovery by myself?
It depends on skills and know how, each case is different, better ask before trying anything with your disk... And better do not trust Youtube videos, where everything looks easy.
3. Can i change heads from one to another disk?
First of all, if you open the drive, there will be dust inside, and more and more data will be inaccessable. It's not easy to change the heads without special tools, better ask for Data Recovery, otherwise you will destroy the disk.
more points will be added soon, we are still starting ;)