We've noticed a lot of bad power supply adapters in the last few years. These are the little 5, 9 and 12VDC boxes that plug into the wall to power electronic devices like routers, radios and computer peripherals. I'm not sure why this is occurring, but if you have a failed piece of electronics, try a new power supply before you throw it away. In contrast, I can't say I've seen a lot of Apple supplies go bad. They probably specify higher quality components.