See my post above. You CAN NOT directly swap a main board from a different hard drive that's been made in this millenium. I don't care if you somehow find the board that was made immediately before or after the one on your hard drive on an assembly line-it will not work. If you get lucky it JUST won't work. If you get really unlucky, you end up with a drive so corrupted that you need a real pro to get the data off of it(if they can manage it for a price you want to pay).
To have this work, you MUST transplant the EEPROM from the bad board onto the good one, which needs a rework station and a fair bit of expertise to make an even bigger mess by lifting solder pads.
I found out about the board swapping deal when I had actually a rather good Toshiba 60gb 7200rpm 2.5" PATA drive that I fried in an external enclosure by connecting it backwards. Those have a 44 pin connector that carries both power and data, so if you do that, bad things can happen.
The drive had some rather important data on it, so I found a loose board on Ebay, swapped them, and found it didn't work.
As a last ditch, though, I started looking VERY closely at the dead board and found that I'd actually blown one of the tiny surface mount fuses. Somehow or another(and I don't have a clue where I found it) I found what value it was supposed to be. I then figured I had nothing to loose, so I pulled out my micrometer and pulled up a table of fuse current of copper wire. I clipped a single strand off maybe a 28 gauge stranded wire, found it was a tiny bit too big, so took my pocket knife and made a tiny nick in it and said it was probably in the ballpark of the correct fuse current. I soldered it on where the fuse had been, and amazingly enough it worked. I was able to "unscramble" the corrupted data with Disk Warrior and get what I needed off.
Funny enough, it was a good enough drive that I figured "why not" and put it back into service in a non-critical application. It went into an 867mhz Titanium PowerBook. I just used that computer about two weeks ago and it still works perfectly on that drive I fixed maybe in 2014 or so.