I vote stuck switch! I used to tap mine (like packing an analog, but upside down) to un-stick them. This is a problem I forgot I used to have til reading this post. These auto-batt's are mechanical not microphone. Sound never effected mine. Believe me, I'm an A/V technician who installs auditorium and stadium sound systems. If an 1800 lb cluster pumping out 20,000 watts won't trigger it, nothing will. You need to carry RN4081's cart down so the diaphragm switch inside the battery doesn't get soaked. Stand it up when not in use, especially if you drip.