Remove the guard over the chain drive for the rollers and I bet you will
find that the chain keeps jumping a tooth on one of the sprockets. This is
due to stretch in the chain. You need to replace the chain. I own a tool
repair shop and I have had to replace several of these for customers who had
the same symptoms.
Doug

" wrote in message
...
Have a few year old DeWalt 733 that recently started behavior of
making a loud "thunk" noise as board is fed through machine. When
this happens, the board stops dead in it's tracks (only for a
millisecond), it continues through, and then there is usually a divot
in the board where the thunk occurred. It was a gradual thing at
first, but now it happens regularly. I replaced the blades today with
new ones...same thing. I cleaned the rollers with denatured alcohol,
have even tried 120grit sandpaper on them, and waxed the in/out feed
tables...same thing. I'm planing poplar if it matters at all. I'm
only planing 1/64" or so when this happens, but it happens at other
removal thicknesses also. Is my next stop the service center??

Cheers