4-26-2012 Fix for Neato XV-11 "bumper is stuck"

Update on the "Bumper Is Stuck" message.   This problem was starting to happen a lot.   So, I followed my original diagnosis that debris was collecting in the bumper slide channel giving the return spring too much resistance.  My remedy was to loosen the two screws on each side on the front bumper and use my compressor to blow debris from the short slide channel.  Then (and this may not be necessary) I squirted a tiny bit of silicon lubricant in channel and tightened the screws (not a lot).   It has been a week now and the Neato #3 has run everyday without a single problem.  Empirically, this seems to be the solution.   I went from 6 to 10 "bumper is stuck" to zero.  Caution-do not dissemble the bumper or put more than a very small bit of lubricant in as doing so could void the Neato warranty (just guessing here).