I got one of these last year and the newer models come with a hex drive that you can adust the depth thru a router table.  Well, I've been doing a number of things and on the next cut needed to change the depth a bit.   There must have been a lot of sawdust in the drive because when I tried changing it, it was not working right.  Took it out and found out the little retaining clip (External-E E-Clip) must have been stressed and popped off, so word to the wise, keep that thing clean and don't go beyond the stop.

...and you can never find those little suckers when they pop off...