The following was taken from Commodore service manuals and technical news letters, plus CBUG. Post date is last update, this record will be updated as new tips are located.
The most useful thing here is the match between the blink codes and the location on the PCB/part that is faulty.
More Commodore IEEE Drive Blink Codes
If the drive seems OK but will not locate (file not found) or run programs, try this:
...this command will help the drive head find its way back on track. That and cleaning the drive head itself with isopropyl alcohol is often the solution to a lazy drive.