Uggh! My early warning signal didn't work!!
 

Okay, so I'm supposed to get a warning when my bobbin is almost empty. Sewed one whole side of binding, got ready to turn and hello....out of bobbin thread! I checked and the ringer is on and set to loud so I can hear it above my sewing. Do I take it in for something like this? It seems so minor, but apparently I really need it!

I wish I had a warning bell. LOL

Was the bobbin different in any way? Like old or hazy? I'd wait until it did it again with a different bobbin, just in case it was just having trouble with that particular one.

dust out the bobbin case might help

My machine has an early warning as well - and when it stopped working I found a bit of of lint that was missed in the area of the sensor. I just followed the bobbin thread and made sure the entire pathway was clear of lint and it started working again.

My Bernina 1530 has no warning bell but if I listen carefully, my Bernina makes a slightly different noise. I learned that from my dealer.

Were you using purchased pre-wound bobbins? Some of these won't trigger the alarm.....

I took mine in once and that was one of my minor issues - he told me it was probably dirty. He cleaned it and it worked great...now it's dirty again. I need to be get my vacuum cleaner out and try that...but I'm lazy.

My machine tells me what percentage of thread I have left when it gets down to 20% so I can plan ahead -- so I don't have to change thread at an inappropriate place. We are so spoiled!

Mine has no warning either, but I can hear a slight difference in sound--if I'm paying enough attention! :)