My Pro-668/WS1088 developed an issue. When I plug in my headphones or a 3.5mm cord to plug into the aux on my car's head unit the squelch opens and the speaker goes to full volume and then some. The display starts to flash and the battery icon shows the battery is drained. When I unplug the headphones the radio quiets down and operates normally. Any suggestions as to what the problem is and any possible solutions, other than the obvious of not plugging in the headphones.