I work in the IT department for my company and we utilize Motorola SL300s for our radios. I have two SL300s though, that anytime they are turned on they play a continuous tone and none of the button presses will stop it. I can still adjust the volume. The only thing that will stop it is if the channel selector gets moved or even just nudged. I have not been able to find anything about it online. It only makes the tone if the channel is set to one on start. if it is set to two, the tone does not sound. Once, the tone stops the radio operates as normal. Has anyone dealt with this before?