Automatic Card Shuffler - fixed!

The Automatic Card Shuffler did not work properly. Only one side fed cards.
My Options: Trash it or attempt to fix it and learn something and teach my grandchildren how to analyze problems [to not throw things away immediately] even if we could not fix it. I choose the latter.
Adam and I disassembled the unit with a jewelers screw driver. We compared the faulty side with the fully functional side. We discussed the entire operation from power to each motor to how rotating gears work to pushing the cards off the stack. We observed the bad side gears would bind at one point when we rotated the gears by hand. When we removed the gear at the motor shaft, the remaining gears did NOT bind telling us that problem was with that gear or the one it meshed with.
Using a magnifying glass we observed the problem was with the gear we removed. The tooth to tooth space was wider in one spot. With no other option, I decided to file the tooth a bit hoping it would still drive the gear train yet mesh a bit better.
It WORKED as you can see. And it was a good learning experience for Adam and Rachel as she watched at times and offered a few suggestions.