Turned my attention to a dead CBM 2040 drive. Totally dead, no power. First thing I checked was the fuse, but it was ok. Next I checked the voltages coming into the transformer, nothing. Click image for larger view.
Found the problem. The person who serviced this drive whatever years ago attached one of the power switch wires to the outer post of the fuse holder, but did not make sure that there was an actual connection to the fuse itself. Almost looks like a homebrew cigar ring or something. Click image for larger view.
I replaced the entire fuse holder. Not a perfect fit but close enough. Click image for larger view.
Click image for larger view.
After re-assembling the power supply I fired up the drive. Cap C31 blow immediately. Otherwise the drive fired up nicely and initialized. With a bad C31 one can run the drive for a little while but eventually the associated voltage regulator will blow out too. Click image for larger view.
Drive D1 is a little sluggish, needs service. Pictured is what it looks like when the drive and computer don't quite synch their messages. After working with the drive to exercise it, performance improved. Click image for larger view.
NEXT - Fix cap C31, grease/lube the drives. These are Shugart 390's which are more or less 400's if I need parts. Nice thing about the 2040's is that they're easy to work on.