I've just bought one of the slim line LaCie USB DVD+-R/CD-R burners and I can't get it to work at all using only USB power. It works fine with mains power but the additional USB power cable doesn't seem to provide any juice whatsoever. With the switch on the rear of the unit in the EXT position, plugging in the mains power supply causes the green power light to come on. Plugging in just the USB data cable on its own does not bring on the green light.
If I move the switch from EXT to USB, plugging in the additional USB power lead does not bring the green light on, but plugging in the USB data cable on its own does switch it on.
The results are the same no matter which USB port is used for each cable. This would seem to suggest that the switch works correctly in switching to and from USB and external power, but that perhaps the cable is defective. To help me try and eliminate it as the culprit, or confirm its guilt, can anyone who has one of these devices confirm if plugging in the USB power cable on its own activates the green power light?