I'm so sorry to hear you're having problems with your D2. I'm still using my D1 w/floppy disk. Got it in 2000 but now use it basically for piecing. Haven't had it in the shop for cleaning for 4 years and have made quite a few quilt tops with it. I do clean out the bobbin area as best I can between bobbin changes but am having problems with the screen these days. Seems its off kilter a bit as I can't get to the adjusting stitch length at the bottom right of the screen. Takes a bunch of times hitting it in various locations before I finally get the screen I want. Thank goodness I don't have to go to that screen very often. I programmed my scant 1/4" stitch into the machine and can go there when I'm piecing. Have another machine I use for embroidery these days.
Would love to have the Topaz 50 but its not in the budget these days and I'm waiting till the D1 takes its final nose dive before I get another machine.