3. THIS POSTMAN RINGS ONCE
Before you reconnect the household power, check all of your wiring with a multimeter. Restore power and program the MP3 player to play a song once (i.e., don't repeat songs) and don't power off (i.e., don't power down or enter "sleep" mode). Run outside and press the doorbell button. Nah, go ahead, press it again and again. Your home now has a personality. It's own dingtone.