Originally Posted by
peacebypiece
Sounds like your top thread was not working properly. Perhaps the thread slipped out of the take-up lever, then lack of tension & all that extra thread underneath got tangled up. Also sounds like you did the right thing to "fix" it. Taking off the throat plate is not likely to void the warranty, since most machines now have changable throat plates for different types of sewing.
How about embroidering a very small motif over the hole. I'm thinking tiny flower or ladybug, etc.
I have the Elna version of this same machine and everytime I have this issues (which isn't often and usually only when I've been sewing fast and hard) it's because the top thread has slipped out of the take-up lever. The way this machine is made it's not quickly obvious--so always re-thread the machine. And no, you did not void the warranty. I agree an embroidered motif, or maybe an applique. Sounds like you may have been working on a T-shirt quilt--what about a pocket from another shirt?