The robot pool cleaner suddenly just halts its progress across the pool floor. The transformer continues but everything else just dies. When I start to pull it out of the water it will usually start again. After a few minutes of normal operation it just stops again.

It is not a matter of worn belts because I have pulled the unit close to the surface when it is in its frozen state and nothing is moving.

There are two major parts in the unit, the pump and I what I imagine is the computer. Is it likely to be the computer? (Anybody else had this problem?)