Maytronics M600 - Red Light after a few seconds

I have a Maytronics M600 that is now out of warranty. The unit will start forward, start backwards, and the impeller will go for a few second. At that time it shuts off and indicates with the Red LED on the front of the cleaner and ultimately the red ring on the power supply. Things I have looked at:

1. impeller is clear of any debris, and it moves freely in both directions
2. I have cleaned all intakes and debris basket
3. brushes and gears work in both directions
4. no moisture in the motor box
5. no burnt up ends, cables, or connections that can be seen in the motor box of the unit
6. tested the battery pack and got 29
7. looked at the internals of the anti-twist cable enclosure and none of the connections in the plug are damaged or corroded
8. tested continuity from the anti-twist device to the motor of the unit and it does

Any suggestions would be greatly appreciated.