I have a DeWalt DW733 portable thickness planer, which is about 15 years old. I need help troubleshooting a problem. Recently while planing some rough-sawn cedar, the planer started making a "clunk" sound about every two seconds. With each clunk, the work piece stopped feeding briefly. After planing, the work piece had a very slight snipe mark every few inches. At first, I thought it might be dull knives, so I replaced them with a new set. That did not solve the problem. I then ran the planer with no work piece. Viewing from the infeed side, I noticed that the left end of the rubber feed roller on the outfeed side would drop down briefly, maybe about 1/8 inch, with each clunk sound. The right end would remain in its normal place. Later that day, I noticed a piece of deformed plastic on the floor near the planer. See a photo at http://share.plaidflannel.com/Planer_Part.jpg. This piece seems like it could be a damaged washer or bushing of some kind that could be related to the misbehaving feed roller. An exploded parts diagram of the DW733 is at http://plaidflannel.com/DW733_Exploded_Parts.pdf. I would appreciate suggestions on how to repair the tool, if possible. I believe DeWalt no longer sells parts for this model, but some third-party companies my have them. Is this something I can do myself, or would the reassembly of the tool require precision alignment tasks not suitable for a novice?