I have an old 80GB Seagate Baracuda Harddisk.
It fell on my toe.
That time it was working fine.
But today as I turned my pc on and this happened.
Can replacing the circuit board will help me recover my data?
Am I doomed?
No, that circuit board has hard drive specific infrmation, changing it is worth trying but rarely works.
A better bet is to try to solder two new components on it, but the problem is that you don't have an idea which exact components you are looking at. You could try to measure the ones nearby to get an idea of their value. But even if you pull that off; if someone else is damaged in a non-visible way, it'll just break again...
The other option is a professional, but that'll cost a lot.
TL;DR: Be careful when handling with your data and take back-ups.
Yes and no.
Assuming only the PCB got damaged: Get an identical PCB with the same firmware and it might work.
If it damaged more, e.g. sent a power spike through the RW heads, then your chances go way down.
Preferred solutions (in order) are: