there's not a trace option exactly. Look on page 62, There's a button that "moves the frame to check the position". On my PE500, you push this 'button' and it takes you to one corner and stops, push it again and it takes you to the next etc. What I did was carefully turn the wheel to lower the needle and make a tiny mark with a washable fabric marker, raise the needle then go to the next corner and repeat. I think the 770 works the same way.