I don't use my dewalt sander that much but it's handy and useful. Using
it the other day and I held it off the workpiece for several seconds
while I was looking for dips, etc. The sander started spinning very fast
and I shut if off before starting to sand again.

I don't remember this ever happening so I guess something's either
broken or maybe it's dirty and instead of spinning randomly and orbital
it's only doing random or orbital. This make sense? Anyone seen this?
What's the cure? It's spinning so fast that if I were to continue
sanding without first shutting it off I'd be destroying the work
unless I was able to lay it perfectly flat on the surface.

When it's on the work it seems fine but without any resistance it
starts spinning very fast.