"Jim" wrote in message
The power switch must be turned off to allow the mechanism to work, and
too much dust clogs the switch (a slide switch) such that it can't be
moved. Thus the router jams and won't move.

The switch must be in the off position as opposed to cutting the power with
an auxiliary switch? While a good safety measure, it would be a PITA when
making a series of small adjustments if the router is enclosed.