@HiProfile, there are two common failure modes. The usual failure is a shorted 12V TVS diode at location D4 on the HDD PCB. The solution is to remove it. Unfortunately WD’s overvoltage protection is seriously inadequate, so there may be additional catastrophic damage. If so, then a PCB swap and firmware transfer (U12) will be required. This should cost US$50 at most.
Catastrophic failures in Western Digital PCBs:
http://www.hddoracle.com/viewtopic.php?t=1119
http://malthus.mooo.com/viewtopic.php?t=1119
Sometimes the USB-SATA bridge board also fails. Typically the dual MOSFET power switch will burn up. The solution is to bypass it.
Repairing Bridge PCBs in External HDDs:
http://www.hddoracle.com/viewtopic.php?t=155
http://malthus.mooo.com/viewtopic.php?t=155
If you are a good tech, or if you have a friend who is capable in this regard, then a DIY repair should be reasonably cheap. No need to part with big $$$ just yet.
