Been tinkering on my 11S for a couple days and are at wits end. It . The roller brush spins easily . cleaned and lubed the bearing on the end of the brush . I have dis assembled it to the inside of the motordrive assembly . The bearing was froze up so with the help of Kroil it spins free. I connected the motor attached to the drive belt assembly to my 12v lawn mower battery and it runs smooth as a clock. I reinstalled it back in the vac and fired it up . It travels around like normal but the brush spins for about 1.5 seconds and stops then in a few seconds spins again. This will go on for about 30 seconds then I get the 4 beeps and solid red light. I can hit the start button and it will start the process all over .Its so uniform its almost like its an electronic issue vs mechanical unless the motor has just had enough. I searched and can find plenty of replacement motor/drive assembly for other models cheap enough but none for the 11S The brush spins easily by hand . Its about 15 months old so Im kind of on my own.