How to repair the 9 Beep Error
You may notice your Roomba exhibit a strange movement that you don't normally see. The Roomba starts a cleaning cycle and things are just fine until the Roomba encounters an object with the front bumper. The Roomba stops, backs up, goes forward, spins, goes forward again, spins and may eventually stop and give you an error with 9 beeps. This is a well documented error that can be resolved only by replacing the internal bumper sensor assembly that consists of an Infrared transmitter and its companion IR receiver. The best way to replace the sensor unit is to dis-assemble the Roomba so that the two bumper sensor assemblies can be removed and then taken apart to access the two electronic components and replace them.
Start by removing the battery access plate and lift out the battery. Then remove the bottom plate so you can remove the CHM, the two drive wheels, and the side brush. Also remove the dust bin.