I've always wanted a Roomba, but could never really justify spending such a large amount of money when my old walmart special vac still works just fine. So I was overjoyed the other night when I stumbled across a 500 series in a local thrift store for $35.
Even better when I got it home, after giving the brushes a good cleaning, it started right up! the battery was weak, so I have been running it until it dies and then letting it charge overnight. After two nights of this, I had gotten from about 15 minutes of run time to 60-70 minutes.
Anyway, last night I set it in our bedroom and let it go for another full drain. It hit a couple of surprises under the bed and needed rescuing a couple of times, but was humming along smoothly for the most part. Then suddenly it stopped and wanted it brushes cleaned. I cleaned them and sent it on its way, and a short time later gave the same message.
You can guess where this is going. It thinks its brushes are jammed. fortunately when this happened I found this site, and have since cleaned the yellow end bearings, and opened up the gearbox and cleaned all the crud out of there (didn't have white grease, so I have not yet re-lubed, will try that tonight), and also checked to make sure the little motor hold up wire was still attached. The motor will spin both directions with a 9v battery, and I also put it in manual diagnostic mode and the brush test will spin the brushes backwards for a second, then run them forward until I stop it. But if I put it on a floor (carpet or hardwood), the motor acts like the brushes are jammed, and runs the motor forward a little, then reverses
Anything else I can try? I read on there the try running it with out one or both of the brushes, which I will try tonight.