Batboard

My UHF Astro Saber III recently began going into intermittent "Self-Check". When the unit is turned on it does its initial Self-Check, displays the selected mode/channel but then beeps and returns to Self Check intermittently at 3-second intervals. The unit, purchased on eBay, has been working flawlessly for 5 or so months. Any suggestions on what could be causing the problem. I purchases the appropriate RSS. Could reprogramming the unit correct the problem?
Charlie

Tighten those nuts down bottom of the radio, I had a problem with that, everytime I just moved alittle, it restarted the radio and went into self test over and over.