Yesterday, I was visiting a store which has come to be a reliable source of old vacs for me. They often have a number of junker vacs in the back of the store. On my latest trip, I found this bright little Hell-raiser, a Hoover DAM Model U6003. From the decalomania, I take this to be one of their later offerings of this model.
This particular one was somewhat rickety and one wheel dragged. I could tell something was wrong "under the hood." I plugged it in at the store, and it ran plus the power drive worked properly. When I got it home, I took the hood off and right away the problem was obvious. There are four machine screws that hold the power drive transmission in place; one was missing and the other three were loose. Once I corrected this, the machine was stable again. These machines do not have a solid, one-piece metal undercarriage. What it amounts to is a system of brackets that are screwed together to form a platform for the power drive and brush roll which the hood screws onto. The Concept series and the later Powermax are made the same way. If you can work on one, you can work on all similar.
The belts in this particular machine were new. The black cord is, I'm sure, a replacement and is in fine condition. Someone was leery of the strain relief on the cord and placed a plastic zip tie around it on the handle to keep it from flexing although it's new and unbroken. Kinda like driving your new car with seat covers on it.
I cleaned it up and zoomed around the family room with it a bit and it's a very nice machine. I have another one of these, an earlier Model 1173, so now that I've got two of them, I guess that makes me a collector.