i have the Janome 634D, which has always been a pain to thread if you aren't able to tie on to the threads already threaded. However i've always been able to get it eventually, now it threads, sews a few inches and then the right needle thread breaks. thought i'd sew with just the left needle, then the thread broke anyway. haven't had it serviced since i had to replace a cutter blade 4 years ago. Perhaps it is time again