My red dirt devil vacuum is "sucking" properly, but recently, when I put it on carpet, the beater bar does not turn. It doesn't matter what setting it's on, it doesn't seem to want to turn.
Don't know why this works, but it does!! If you remove the bottom plate, take the roller brush out and make sure there's no "gunk" on either side of the roller--you'll probably find lots of dirt, dust and dog hair! Remove that, make sure the belt is tight, then put the roller back. I did this on the recommendation of "Dirt Devil" and didn't see how it would even matter--but it did!!!! Now my vacuum is working just fine!!!!