There are relatively few things to go wrong with one of these.
Check if your PPC works with other SD memory cards to see if it's the PPC that's the problem.
Try it in another device to see if it's the card that's the problem.
If the PPC works with other cards, and the card works in other devices, then it must be a combination of your PPC and your card, so try upgrading the ROM in your PPC.
Ian, May 2006
