Panasonic SA-BTT775GA Service Manual page 81

Step 12 Push and press the turning shaft of the Mid Base side-
way, a "click" sound is heard when is fully insert.
Step 13 Slide the Slide Cam until it come to a stop.
Step 14 Insert OPU FFC Sheet as show a "click" sound is
heard when the OPU FFC is fully catched.
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