Aquabot Turbo (2006) won't reliably reverse

by David K
(Greesnboro NC)

My 2006 Aquabot Turbo recently wrapped its cord into the brushes. After clearing, the robot will not reverse.
However, it does start out correctly, climbs the wall, then stops for two to three seconds to reverse direction, but does not reverse, it goes forward again. It does not seem to matter if I grab the brushes and try to force a reverse direction. I removed the drive motor, checked the circuit board but did NOT replace any components, and ensured the motor was free to turn. Now hear is what is interesteng....I re-assembled the motor and dry tested it
(just the motor, not the pump). It started correctly, stopped momentarily for a few seconds, and reversed direction! I
thought the problem was somehow resolved by just re-seating the circuit board. But when I re-assembled the
entire unit, it went back to not reversing!
I'm asking if anyone has any ideas or suggestions. Can anyone tell me what causes the motor to reverse directions? Is it a timer and a particular Capacitor, or something else? I thought that if the motor gears were binding, it would not keep going forward? Perhaps if the Capacitor was bad or weak(?) it could not reverse the motor direction under load?
Obviously I'm at a loss, so thanks in advance for any ideas or suggestions.
ADMIN REPLY: My first thought is damaged drive belts that engage only one direction. Often the teeth on the belts will be destroyed when the wheels can't turn freely. The belts will also stretch. With the robot running, watch the drive gear where it drives the belts. Check that the gear reverses. If it does...try new belts