Turn the head over and you will find a 1/2" wide rectangular hole in the edge of the locking plate under the drive clutch. If you move the locking lever to one side and look deep into that hole, you will see a screw head at the bottom. With a long screw driver, remove the screw. (The head is the same as the two that hold the locking lever in place) That done, move the locking lever all the way to the other side and repeat the process. Then you can lift the cover off from that end of the head. Replacing the screws is a bit of a problem. I squeeze some mastic (Putty works well) into the screw slot and this holds the screw on the screw driver for reinserting. Good Luck.
Bawdy Bill, February 2011