Hey guys. Today I got this used Simplicity G9.4 in rather good condition for $100 off of Facebook marketplace, however an issue has arisen. When the direct air motor is activated, there seems to be a vibrating or rattling noise that is not present in the upright position or when the direct air motor is deactivated. It sounds almost like a vibrating fan or brush roll, however as I am not well versed with the mechanics of these machines I am unsure. The brush strips are loose in the aluminum housing, however I do not believe this is the cause, but I cant be sure. I have linked a video I made of the vacuum below so you can see for yourself what I am talking about. Any help would be greatly appreciated, as this has been one of my dream vacuums for a while and I would like to be able to use it without worry. Thank you.