PM me for more info on The C4 control, I have spare parts available.
When working with the SD drives, try running one drive at a time. completely disconnect to other 2 drives. try swapping one at a time. The SD drive have been known to "cascade" a problem from 1 drive to the others. I have rebuild drives.
If you do not have +/- 15 VDC the drives wont work. I have replacement power supplies as well.
Sportybob