Answered: PIC Controller Overheating

We are having problems with the PIC controller on one of our classroom robots. We have two 3-wire motors, a bumper switch and an LED plugged into the controller.

The students starting having problems downloading their program to the controller and we noticed the controller smelled hot. We unplugged all the devices and were able to download their program, and we gradually added devices back and it stopped working when the bumper switch was plugged in. The students put on a brand new bumper switch but continued to have intermittent problems downloading their code. They managed to get the online code to download and tested the devices…the bumper switch value changed when the switch was pressed and LED would turn off and on when the digital output checkbox was checked and unchecked, but they were unable to get the motors to run on any motor port using the sliders.

Any ideas?


Can you run your motors on default code?
Try downloading the default code and controlling your robot with the FM transmitter.

Let me know your findings.


We are having intermittent failures when trying to download programs to the controller…we found that when the downloads fail unplugging all devices from the controller helped.

We downloaded the default code as you requested and were unable to drive the robot…the motors would not run. We also downloaded the on-line code but were unable to control the motors. With the on-line code loaded we plugged an LED into a digital output port and were able to turn it off and on, but could not get the motors to run no matter what motor port we tried.


Please contact VEX Technical Support for further troubleshooting.
VEX contact information is listed here: