Polaris 280 was not cleaning properly. It would get stuck because the teeth on the inside of the wheels were worn down and the drive shaft was slipping.
I just completed a rebuild of my 280 and it has a place it gets hung up on in my pool which is quite curvy. I've tried everything and it goes into backup mode and that pulls it perpetually into the same position to start being stuck all over again.
I have this same issue, right by the stairs, there is a certain spot that if it comes in at the right angle the body hits vs the wheels and it gets stuck, the problem is that it happens every day even if I place it on the other side of the pool, it goes right back to the same spot. thinking a 4 wheel version might solve the problem. ugh.
