G-Tech G Drive - Power Issues

[dazzer21]

I've got three 500GB G-Drives connected directly (USB/FW400/FW800) to an iMac which have run perfectly ever since I got them about (hopefully less than) three years ago. Have anyone else experienced with these drives the power supply develop a problem where power is getting through to the drive, but not enough to enable it to be seen on a network. The front light just flashes. When I swap power supplies with the 'good' one, the drives work fine. Both of the faulty ones have happened within a couple of days of each other. have tried plugging them into different wall sockets etc, but no joy. Just wondered if this was at all commonplace (I'm emailing G-Tech but so far they haven't come back to me...)