Its the spektrum radio. I bought my son one and had same issue with his lrp speedo. He had a new spektum dx3 and a 2007 lrp sphere and it would cog sometimes and other times it would just go full tilt and not stop. I replaced sensor wire checked all connections. this is what i found on spektrum site when i had problems and to make sure it was the radio I pulled my futaba receiver out of my car and put it in his not one problem.

I have heard of issues with some Speed Controls not working properly. What is the cause of this? - 12/28/2007 1:55:33 PM



Depending on the manufacturer of the ESC, there can be issues with the BEC (battery elimination circuitry) not having a high enough voltage output. The issues tend to be isolated with Tekin and LRP ESC’s when used with SR3000 or SR3001 receivers. There are several steps that can be taken to prevent issues from cropping up. First is to make sure you install a power capacitor on the speed control itself, as this seems to prevent high-current drains from causing issues on the ESC’s end. Additionally, installing the SPM1600 Voltage Protector into an open channel on your receiver can further prevent low-voltage issues.

My solution was buying a new radio for him.