FireWire drive’s LED works – even when there are power issues.

If you ever experience a condition where your FireWire drive appears to have power – meaning the LED is illuminated – but won’t work, you should check your power carefully. In some cases the power or drive activity LED of firewire drives will light up when connected to an active FireWire bus even if the drive is not turned on. This is because some power is supplied on a FireWire bus for certain devices that can use it, and if your device is wired just right some of that power may get passed on to the indicators even though the dedicated power supply is not activated. This condition will not cause any harm to any equipment, but could be frustrating and misleading when trying to troubleshoot why you’re drive isn’t recognized by the computer.