TYLERJM

I'm having a strange situation with the thread tension on a juki LU1508N. To get the stitch to "look" like the tension is right (no threads peeking through the opposite side), i have to have the top thread extremely tight and the bobbin extremely loose. I have about 10 of these machines and this is the only one with this issue. Its also skipping stitches intermittently... not sure if that is a related problem or not. Does anyone have any ideas how/why this is happening and how to fix it? Thanks!