The above pictures are from the Robie Jr. ® and Omni Jr. ® robot. This will give you an insite of the inside of the robot.
REFERENCE: Omni Jr. ® ; Robie Jr. ® & Omnibot Jr. ® Repairs Questions & Answers:
Q. The (Robots Jr.) does not move forward or backward or right or left and the switch is ON ?
A. Check the Batteries and if they are bad, replace them.
Q. If the Batteries are good what then?
A. Make sure that they are making a good connection. Check the connection for the terminals can be oxidized or corroded.
A. Directly check the Motor by applying DC voltage directly to the motor.
The (Robots Jr.) Works but keeps loosing power and goes dead when bumped or is running?
A. The battries is losing contact from oxidation or corrosion. Use the Batteries replacement in the Repairs Section - Robie Jr. ® Battery Replacement