I have a Janome 4800 QE, which I've owned for about 6 years, a wonderful machine for piecing, but when I try FMQ I get the top thread coming through on the bottom of the quilt. I have sat with a practice piece and gone from 1-9 on the tension control, moving it up half a number at a time, and there's no setting at which this doesn't happen. It improves a bit around no.7. but is still not good. The shop say there's nothing wrong with the machine and it must be me. I have tried all sorts of threads and needles. The only near-success was with embroidery thread - but I don't want to be limited to just one type. I would be grateful for any help or advice on thread, needles, technique, before this machine goes through the window. OK, it's not top of the range, but it wasn't cheap either, and I do think that to expect a "quilter's edition" machine to quilt isn't unreasonable!