I’m okay with appliance making cute little dings or buzzes but if they chime out a full song it creeps me right out. I’m gonna get the clothes out of the wash you don’t have to scream “Mary had a Little Lamb” at me.
My hot water boiler / warmer loudly plays Fur Elise for 10 or more seconds after it has brought a fresh tank to boil. Most of the time I don’t care, but at 6:30 in the morning its loud I worry about waking people even with closed doors.
Shoot some Great Stuff into the speaker hole. (Not really, no, don’t do this with something that heats up).
You could open it up, find the little speaker (probably a tiny little thing) and disconnect it or put some glue in it (like Goop).
Hold the unlock button for for 3 seconds and it will change the song to 3 beeps. Do it again to mute it.