I fried my old PCB and found a new PCB on ebay with the exact Series number and P/N number (including same firmware). When I boot it up though it wont show up in bios and it keeps doing a bad data read noise (when the head hits the middle to reset it). Anyone have any idea how I could make this work? It is a ST3500418AS, P/N 9SL142-302
I would advise that you avoid those suppliers who don't tell you that a board won't work without modification. Often they will attempt to obscure the requirement for a firmware transfer by deceptively describing their products as being "for data recovery only".
Alternatively, if you are not adept at soldering, your local TV/AV repair shop should be able to transfer the chip for you.
Onepcbsolution.com also offer a firmware transfer service for US$20 if you have purchased your board from a different supplier: