I just purchased a Delta DP350 drill press on ebay. When I assembled and tested the unit, the unit started making a funny sound when I moved the speed control to the lowest setting. I opened the top panel and the spring, cap, and retaining ring had popped off of the drive pulley. I was able to re-compress the spring and install the retaining ring. When I started it up and moved the speed control to the lowest speed setting, there was another "POP" and again the retaining ring had let loose releasing the cap and spring from the top of the drive pulley.
Anyone else seen this problem? Seems like when you go to the lowest speed, it puts more tension on the drive belt. I'm not sure if the problem is in the retaining ring or the variable speed stuff.
BTW, that's it for me on ebay. I've had too many bad experiences. This DP was advertized as "never used". Now I can see why. The wear on the top screws indicated to me that this problem was known.