I bought a 24779 model (Petmate Portion Right) a few month ago for my cats.
Even though I live in a VERY dry area (cat food does not weigh much, as it is not  humid), the rotating plastic blades got all bent - and USELESS - pretty fast.
Had to dismantle the unit completely to get to it, and put them straight again after having dipped them in Hot water.
Then, for no apparent reason, the entire electronic system went dead!
Batteries are A OK, Power arrives to the board, but the dial (complete board, really) is/are dead: Impossible to program anything, and pushing the right button does not make the motor to turn either.
Now I'm in serious trouble, as I have to go away, and I have no solution for feeding my cats!
What a waste!