Blue Chip BCD/5.25 floppy drive schematics.

I dug my C64 system out of storage and am trying to get it all working again. It's all working now except for my 3rd drive, the Blue Chip. I can communicate with it. The disk spins, but the head doesn't move. I'm not having any luck tracking down schematics or service manual. Can anyone help me out? The main board is PCB NO 138 Rev C-1A. The lower interface board is 1380685 with no rev indicated.