Thanks, All!
* I changed the needle to a Embroidery 75/11, which gave a much better appearance for what I was trying to accomplish.
* And I reduced the upper tension to 2.25 and
* did a thorough cleaning for all loose threads on the interior of the bobbin case area.
No more breakage
I did find that the Isacord would shred after so much sewing, so I switched to King Tut, and had no breakage and MUCH better appearance (I was doing a lot of small lettering, and the King Tut was just a better looking thread than the Isacord which seemed to thin (both were 40 weight). And I slowed down the speed to 50% or 75% of the max speed. YEAH!
I also figured out that when I actually close the bobbin door on the sewing machine I would NOT get the warning to clean the bobbin case (I never closed it while sewing in the past).
Thank you, All, for your advice!!!
Mary Kay