Continuous Motor Running

The motor attached to the second port on my logic mod, runs continuously. I do not have a servo attached. Any motor I attach to motor port 2 runs continuously, will not run in reverse, and only stops when I adjust the trim to -150.

Mostly likely the problem is in the Vex Transmitter. If you have changed the program in the Vex Controller, download the Vex Default Firmware using the IFI_Loader – both are on the Downloads web page If you have another Vex Transmitter, try that to verify the problem is in the transmitter. If you have not changed the program and have purchased the unit from us, you can send the Vex Transmitter to us for repair if it is still under warranty. This applies to any Motor Port that runs continuously. Otherwise, you will need to contact the place of purchase and follow their warranty/return policies.

I have my VEX module in ‘12’ arcade mode with the standard squarebot. I am using Channel 3 and 4 to drive two other servo motors of a pan/tilt mechanism with a video camera. The Channel 3 motor output is not working like the other motor outputs. When the joystick is in the center, the motor output is high for 800 us instead of 1.5 ms. When the joystick is pressed full left, the motor output is high for 300us instead of 1.0 ms. When the joystick is pushed full right, the motor output is high for 1.3 ms instead of 2.0 ms. I tried to adjust the output with the offset button, but it did not fix the problem. What is wrong with this channel?

First off, I mentioned the wrong servo motor output in the previous post. The channel that is misbehaving is Channel 4, not Channel 3. I also purchased a VEX Programming kit and downloaded the default firmware to the controller with no improvement. What I did notice is that when I downloaded the on-line firmware and controlled the Channel 4 motor with the on-line GUI, the motor behaved properly. Does this point to a bad radio controller?

This points to the Vex Transmitter. Anytime you can not adjust any motor output that has trim adjustments to operate properly, the problem usually is the Vex Transmitter. Using the on-line GUI tells you that the Vex Controller and Vex Motor are operating correctly. You can verify this if you use a different Transmitter and the problem goes away.