Yep, it's the controller.
See the pix.
Notice the hole?
This is what it looks like from the other side.
The inside of the controller has epoxy filled in there so it's totally waterproof. When this thing went, it must have blasted a hole right through the end there!
That also means that you can't just get in and replace a single electronic part.
I am calling Alltrax customer service tommorow. Why do I have the feeling my one year warranty just expired.
See all the photos here:
http://gallery.mac.com/benhdvideoguy#100075