Panasonic SA-PM29P Service Manual page 27

Step 4 : Remove the right cassette holder as arrow shown.
11.14 Procedure for Replacing Pinch Roller and
Head Block (Cassette Mechanism Unit)
Follow the (Step 1) - (Step 6) of Item 11.2.
Follow the (Step 1) - (Step 3) of Item 11.3.
Follow the (Step 1) - (Step 5) of Item 11.4.
11.15 Procedure for Replacing Motor, Capstan Belt
A, Capstan Belt B, and Winding Belt (Cassette
Mechanism Unit)
Follow the (Step 1) - (Step 6) of Item 11.2.
Follow the (Step 1) - (Step 3) of Item 11.3.
Follow the (Step 1) - (Step 5) of Item 11.4.
Follow the (Step 1) - (Step 7) of Item 11.15.