I have a Brother PC 8500 combination sewing/embroidery machine. Sometimes I have a problem with the tension where the thread doesn't want to "catch" in the thread guides. I just had it serviced in December. I'm having that problem today, and I've rethreaded, and changed needles, bobbins, thread spools etc. I make sure I thread it with the pressure foot up. Today I ran into that problem while embroidering, and I changed it over to sewing mode to check it out and it did the same thing there at first, and then sewed fine. Then I went back to embroidery, but no luck. Any suggestions?