Cortex cutting out

Just a day before we left school for Christmas break, I noticed that our robot started cutting out at random points.

We would turn it on, move it for a short amount of time (around 15 seconds probably), then the robot light on the controller would go off, the VEXNet light red and all lights on the robot blinking yellow, as if it was trying to reconnect. Any ideas what could have caused this and how to fix it? We have a competition on January 14th and come back to school on January 5th.

The only thing I can think of that could have caused it was a member of another team at our school who threw a cube, which hit our cortex. The left side of our drive didn’t work for about 5 minutes after that incident, but worked fine after. I don’t think that this would be the cause though, because it wasn’t thrown hard, and I’m guessing a light throw of a cube wouldn’t be enough to damage the cortex or trip any PTCs?

Most likely cause of this is a bad connection between the battery and the cortex. Make sure you use one of the extension cables to connect the batteries to the cortex and that none of the pins in the connectors are bent.

Also, make sure the battery wires are making good contact with the cells in the battery. The simplest way to do this would probably be to plug the battery into the Cortex (with no backup battery), turn it on, and shake the battery (softly enough that the battery wires never become taut). If your Cortex loses power or power-cycles during this process, you should probably avoid using the tested battery.