One weekend I had left my master/avionics switches on, and returned the following weekend to a dead battery. I have a (3400 non S) and have had trouble free flying for about five years. I put my battery on a Battery Tender to recharge. Came back a week later fired everything up, started the engine and I have the AHRS Red X. Never had this problem before. The only thing different was the dead battery. Any ideas on how to reset, or check this? Thanks, appreciate any advise I can get.