usb external drives fail to power up on certain machines

[venm11]

I suspect this is a usb 5v current issue, but I'm not sure. It happens only on certain drives attached to certain computers. They click away when plugged in, failing to start up, and may register in windows as a malfunctioning device. But the errant drive will work fine when plugged into another computer.

This is even with the usb y-cable that supposedly gives 1A.

Any ideas?

Also, does anyone know for certain the exact power jack these drives use? is it 3.5mm x 1.35mm ? there's also x 1.5mm.

 

[staticlag]

How many computers are they having problems on? Is it a specific brand type? Or is it just a single machine?

I would also check them for bad sectors, I have had a lot of external drives come though me with head crash since people tend to beat externals around for some reason.

I have a moterboard that needs an extra molex 4 pin connected to it to give full power to it's USB ports. It might be the case if this is just an isolated machine that you are having this issue on