Roomba Red Problem

Question

Unit worked well until I sent it on a mission to clean after kids were in the house. The following day the unit started waddling like a ruptured duck, it would go forward about a foot then make a partial turn, forward another foot, partial turn. This behavior continued within about a two foot square area until the unit stopped.

I could tap the bumper and the unit would turn and start circling, then would lock in the motion described above.

I did take the unit apart (field stripped it) and cleaned all surfaces with a dry soft cloth and all of the sensors with a Q-Tip (this included the wheels).

Any suggestions?

Thanks: RAnderson