We've received a number of calls and emails about 1693ELs that are unresponsive.
For safety we've fused the circuitry in the stand and it's possible that the fuse has blown. At the top of the stand, where the power cable meets the stand, you'll find a small tray that contains the fuse:
To replace the fuse remove this fuse holder with a pick or a small flat screwdriver. Replacement fuses should be a 6.3A time-delay glass-tube fuse, examples of which are available from McMaster-Carr under part number 6978K754.