Classic 1000-HOB leaking

I started getting a large leak from all sides around where the collection cup sits in the main body. I've tried raising and lowering where the cup sits, and also lowering the rubber O-ring around the cup - all to no avail. I don't want to get rid of the unit, but regardless of what I do, nothing seems to stop the leakage other than unplugging the unit all together. Sruggestions??