Hello,
Western Digital does not sell or replace circuit boards for our hard drives nor are we aware of any other companies that sell them. Replacing the circuit board on a hard drive is not a recommended method for recovering data or drive functions as this will void the warranty on the hard drive. For every hard drive model that Western Digital manufacturers, there are many firmware changes that would make it very difficult to find a circuit board with the same firmware of the defective drive. If you attempt to install a circuit board with a different firmware than the original, this may damage the hard drive further. If you need to recover the data on your drive, please contact one of our recommended preferred data recovery partners.
