I bought a Neato XV-21 "used - like new" from Amazon
a few days ago during a business trip to the US. The robot arrived in its original box and appeared never used but after charging it for 1-2 hours, to my surprise, the robot didn't worked as expected. It kept moving in circles, back and forth... so I guess I got a defective robot which was returned to Amazon
But in my second attempt, it cleaned all the apartment and returned to the base accordingly. It's insane the amount of dust it collected from the carpet - hotel carpet, not mine
After successfully test it a few more times, I decided not to return it to Amazon
but bring it with me to Brazil where I live.
Unfortunately, after get home, it started to present the stuck wheel problem much more often (I got this message on the display). So I decided to inspect it closer and figured out that one of the wheels was much harder to turn by hand than the other one. Because the warranty is not valid in Brazil and I'm not supposed to return to the US soon, I decided to fix it by myself.
I removed both wheels and pulled both drive motors off. Than I realised that the problem was in one of the motors that wasn't spinning smooth enough. I contacted Neato's support and asked them if they could send me a new motor by mail just to hear that they don't send parts and I should return the robot so they can fix it... I searched in eBay
and could find it for $20 + shipping. Before doing that, I decided to plug the motor (+ wheel) in a 5-9v power adaptor and run it for a few hours to smooth the mechanics inside... During this time it became obvious that something was wrong with the motor since it constantly changed its speed between fast and slow periods. Setting the power adaptor to 9V appeared to work better to fix this issue, but I had to pay attention to the temperature and let it "rest" in 5V or unplugged when it got too high (it's not an exact science, sorry). After some hours the motor finally appeared stable, for good or bad, I had no idea yet...
It worked!!!! After putting everything back in place the robot never got stuck again and both wheels are now equally "soft".
Hope my post can help you guys having the same problem...
Difficult level: easy if you have the right tools and a minimum knowledge of electronics.
1 - Turn off the robot
2 - Remove the 4 screws from the wheels cover and open it
3 - Pull the wheel off, removing the spring from the botton and disconnecting it from the main board. (special attention to the left spring so it won't touch the main board)
4 - Get a power adaptor and connect it to the red and black wires on the plug of the motor: http://www.hizook.com/files/users/3/Neato_drive_wheel.jpg
. The 2 adjacent lateral wires on the right of this picture. In my case, it was easier to connect the wires to the back of the plug, instead the front. You can use an alligator and connect direct to the wires too.
5 - Run it for a few hours as described above, adjusting between 5-9V (I used an 1A max adaptor). Don't forget to reverse the polarity too to spin it in both directions.
6 - Put everything back in place and you're done!