WD My Book Studio LX (2TB) Firewire won't recognize

I have a WD My Book Studio LX (2T)  THis is not my first WD drive and I have 21T units which I have used for years. I have had this problem from the beginning with this drive and hope some expert can help. When attched it will not be recognized by my Imac. I am running Yosemite but this happened with the last two OS’s also. The drive will mount with a USB cable but I want to use it for my time machine and the USB2 is much slower. I have tried everything and have the latest firmware installed. 

I have plugged it straight into my computer.

Straight into the wall outlet

changed cable numerous times

restarted the computer

etc

etc

etc

Thanks in advance for any other suggestions

on the WD site the generic answer was install drive manager which I cannot find.

I am not using any of the supplied software

Rob

Hi there,

Have you tried connecting this device to a different computer to check if the same result happens?