Janome 6600P making "tock tock" noise
 

Sewing fine. Haven't hit anything. Cleaned bobbin case and under it. Put a drop of oil on wick. Changed the needle. Seems I've had this happen before & some combination of the above made it stop. Ideas? Oh yeah, I tried a different bobbin too & they are Janome bobbins.

I have a class next Saturday. If I take it in for servicing I doubt I'll have it back in time.

I would try another needle. I know you changed it, but sometimes you get a bad one. Make sure it's all the way up into the shaft.

My first thought is that you do not have the bobbin case set in properly.
It is very easy to think it is in right ... and for it to not be so.
Plus, if it is not sitting properly, you can damage the bobbin case.

Both can cause a tock-tock noise!