on march 7, 2020 i bought the model Thunder Chief with the ez command 3 to 4 times around the track i lost the sound, i read the manual i turned off for 2 minutes to see if it reset,  i make sure not to press the #8 for mute nothing the next day i had the sound back for a few laps around the track and again lost sound. i returned the unit to Amazon they send me a new one. this time it work for one day. this morning the sound is gone again. Is it me doing something wrong or is it that bachmann thunder chief product is defective?