The problem should be solved, I have missed a simple switch design, all I would ever need are just power spliters, for each HDD, I only need to add two power spliters between power supply and Drive, all I need to do is to break these spliter connection when I need to shut HDD down. (well, who needs case cover anyway ;-) PS ---> Spliter 1 ---> spliter 2 ---> HDD ^ disconnect here I would like to thank Frank for his input (which gave the idea why not just pull the plug by hand). Jun Qian PCBUILD's List Owner's: Bob Wright<[log in to unmask]> Drew Dunn<[log in to unmask]>