Panasonic SA-BTT775GA Service Manual page 74

Step 4 Release 5P FFC from the BD Mechanism Unit
(BRS1P).
Step 5 Release 4P FPC from the BD Mechanism Unit
(BRS1P).
Caution: Avoid using strong force, to prevent damage on
the solder area of 4P FPC.
Step 6 Press down the hook.
Step 7 Lift up the Turning Shaft of the Mid Base Unit as shown.
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