on the carriage you will see 2 big buttons/screws. Undo them. This will release the sinker plate from the carriage. Now put it back on again. Believe it or not, just by taking the machine apart & putting it back together again often fixes problems.
Run the carriage up and down the bed with the needles out to make sure that it is running smoothly.
Make sure the weaving brushes & the rubber wheels are not in action.
Are you using 4 ply balls of wool or fine 4 ply coned yarn? There is a HUGE difference in how these yarns are knitted on a machine. Coned 4 ply yarn knits up at Tension 7 or 8. If it is balls of wool then the tension would be around 10 and could still be too thick.
As a beginner it is easier to learn using a fine 4 ply acrylic yarn rather than wool.
maybe find some tips here: www.scanthecat.com
Jo
July 2009