Many hard-drive failures are caused by problems with the PCB. If your hard drive does not spin when powered on, PCB replacement may allow you to recover your data. PCB replacement will not fix all hard-drive failures, however, and like most other do-it-yourself repairs, it may void any remaining warranty on the drive. This process should be used only as a last resort after all other options have been exhausted. If you are not comfortable performing repairs yourself, many data recovery companies will perform this task -- for a fee.
Confirm that the PCB actually needs to be replaced. If your hard drive spins when powered on or makes clicking noises, the fault is mechanical and will require professional data recovery. If the drive does nothing when powered on or shuts off intermittently, the PCB may be at fault.
Locate a suitable replacement PCB. To do this, you will need the model number of the PCB, which is usually etched somewhere on the board itself. To remove the PCB, simply remove the screws that fasten it to the drive and carefully disconnect the ribbon cable. Many hard-drive manufacturers use specially shaped star or hex screws, so be sure to use the appropriate screwdriver to prevent stripping. Tearing the ribbon cable will render the drive unrepairable, so be gentle; it should come free with minimal force.
Purchase a replacement PCB. These can often be difficult to find, though many online resellers offer a wide variety; be sure to contact as many vendors as you can. You will need an identical board, both in physical shape and size as well as model number; substituting different boards may cause permanent data loss.
Connect the replacement PCB. Gently connect the ribbon cable; make sure that it's fully connected before mounting the PCB to the drive with the screws you removed before. Be sure to mount the PCB exactly as the original was mounted.
Test that the new PCB is working by turning off your computer and connecting only the power line to the drive. When you press the power button to turn the computer back on, the drive should spin. If it appears to be spinning properly, turn the computer off again and connect the hard drive as it would normally be configured to recover your data.
Cut the power and disconnect the drive if the hard drive fails to spin or makes any unusual noises when powered on. Ensure that you connected the PCB properly and that it is mounted securely. If you have performed these steps as stated and the hard drive still fails to spin, the problem is likely mechanical and will require professional data recovery.
Replacement PCBs are almost always sold in limited quantities, so be sure to check auction sites and contact speciality vendors.
Don't be tempted to use a similar-looking PCB that is not identical to the original; this will almost always cause damage. Use caution when handling small electronic components. Hard drives are very sensitive to bumps; a small fall could do serious damage.