LDOSFI.CX ZX81 Larken Fix

When my Larken ZX81 disk controller arrived I got the 5V DC power wired to the ZX81 controller board. But the most action I got was the drive light would come on at anytime that LDOS went to the drive but the drive motors never came on. After double checking and making sure I had the terminator resistors in place I called Larry and he said the the drive select line had to go to ground. It was a clue but not one I could use.