I've lost my ac adapter to my hp simplesave model MD2000h external hard drive. I know it is 12V and 2A and when I plugged in an adapter with those specs, the HD did not power up. Do I have to use the right wattage? If yes, how would I find out? The HD has no specs written on it and forget about the HP support sites! I just don't want to blow the poor thing up.