I am teaching my students about the various types of sensors which can be used on the EXP robots. I passed out the version 4 bumper sensors to 15 different groups today. On one robot, none of the V4 sensor ports detect any signal from the bumper sensor I gave them. I gave them a different sensor. We had the same results. These two sensors worked just fine on another robot, so I know it is a port issue. Has anyone else experienced this? The brain is still under warranty, so I know I should be able to get it replaced. I am guessing there isn’t a ‘reset’ switch somewhere either??