Janome 6019QC Mechanical Sewing Machine "year 9500 combine" Questions

...9500 is far too tight can I adjust it myself if so how, I initially had a problem where both the thread and bobbin tension were too tight I have managed to get the thread tension loosened but still ...

...9500 , when I embroider, will work fine for a while, then the thread starts knotting up on the underside and makes a loud noise.. Then the needle will not come up. I have to take the hoop out of the ...