Panasonic SA-HT920P Service Manual page 22

Step 1 Release the claw in the direction of arrow (1), and then push drive gear shaft up.
Step 2 Remove Drive Gear (A) and Drive Gear (B).
11.13 Disassembling the Fixed Plate, Magnet and
Clamper
l Follow the (Step 1) - (Step 2) of Item 11.1
l Follow the (Step 1) - (Step 4) of Item 11.2.
Follow the (Step 1) - (Step 5) of Item 11.3.
l
Step 1 Release 3 claws in the direction of arrow.
11.14 Removal of the Cam Gear & Support Piece
l Follow the (Step 1) - (Step 5) of Item 11.3.
Step 1 Rotate (A) in cam gear anti-clockwise.