How to remove top cover of lily 550

SOURCE: Viking Lily - free motion quilting - thread loops on underside.

I need more info.
>Where is your presser fooot pressure set(1-9) it should be around 4?
>How fast are you free motioning (faster is better? from 1-10 10 being full speed.
>Is your bobbin threaded correctly (I need to cover the basics.)?
>Never never use a needle smaller than a 90/14 for free motion (I know everyone's an expert...but trust me)
After all this, it's OK to tighten your tension up on top a little when free motioning and getting eyelashes/spider webs on bottom. around 6 should do it though.

SOURCE: husqvarna viking, interlude 435...unable to solve tension problem

Sounds like the tension unit is at fault. First check the bobbin tension by removing the bobbin case. Use a half-full to 3/4 full bobbin. Be sure it is threaded through the bobbin case with thread hanging straight down with tension spring on top. Tie the stitch plate to the end of the thread. If the thread pulls the bobbin out, the bobbin tension is too loose. If it does not move when "jiggling" the bobbin, it is too tight (which is not likely based on your description). Small screw (through an open hole) on the side of the bobbin case adjusts the tension of the bobbin case. Left for loose and Right for tighter. Otherwise, contact local authorized Husqvarna Viking dealer for their assistance. You can find the closest dealer at the Husqvarna Viking website - http://www.husqvarnaviking.com/us Good luck.

SOURCE: viking husqvarna classica 100, thread tension

I suspect you are correctly threading the machine but the timing of the needle and bobbin hook is off. When the threaded needle goes into the bobbin area, a pointed hook grabs the thread and loops it with the bobbin thread. Something is catching when the needle starts to come up that is not allowing the bobbin thread to be pulled back through the needle plate opening by the upper thread. With machine threaded and bobbin in place, have the bobbin area open if possible and watch the thread interaction when the needle goes down. To set the hook/needle timing, normally covers have to be removed. Suggest taking it to an authorized Husqvarna Viking dealer for service. You can find the nearest dealer by click on the "Dealer" link at http://www.husqvarnaviking.com
Good luck.

SOURCE: When piecing a quilt top,

You need to give it a helping hand over the thick seams. There is a gadget called a jean-a-ma-jig which could help.
Or sew up to the seam, leave the needle in the thread, lift the pressure foot, then insert a thick piece of card from behind to make the foot level with the seam, lower the pressure foot then sew.
The idea is to make a level surface instead of a bump to sew over. Improvise any way you can.

SOURCE: Is the Lily 550 compatible with both 110 and 220 voltage or do I need an electrical converter?

check with the sewvacdoctor.com