Simpson Maxidry 1200 S?

I have a Simpson Maxidry 1200 S, which has started to turn un-evenly; as it rolls, it makes a regular frictional sound (not a grinding, but more as if the drum is rubbing against something as it rolls). Opened up the back, cleaned out the dust and such; motor and belt seem ok, dryer still operating, but running for just a few minutes makes this sound get worse & worse, and you get that 'hot' smell. Should I just take it to the shop, replace, or is this something that's easily repairable? Not a handyman, but also not afraid of having a go.