I finally found some time to resolve the problem. After looking over
the original incorrectly routed pieces I decided that it was a gradual
change in some setting. The only possibilities were the router height
adjustment and the collet. I bought a new collet. It is much
tighter than the old one - so there must have been a lot of wear over
the years. I have been routing dove tails for the last few days with
no problems.

Case Closed (finally)

Len