Pictured is the drive signal/power interface board installed in the chassis of the Cromemco System Three. This board is used to route power to the Persci 299 twin 8" drives, and I believe the drive controller signals. Visually inspect the board. Can you guess what's wrong with this picture? Click image for larger view.
This photo does a better job to display the problem, the 2000uf 50v cap has blown out. Click image for larger view.
Twelve years ago I last worked on this computer as described here. At the time I focused only on the drive itself, I never thought to check the control board between the computer and the drive for faults. Kind of duh.
Since the original thread I tested the drive and I was able to get it working by manually pinching closed the drive heads arm to the disk (carefully). Repairing the 12V line should allow for the pushbutton drive to close so that I don't have to hold it closed manually (ouch).