Panasonic TH-P54Z1D Service Manual page 13

5.1.2. Monitor mode
5.1.2.1. How to access
1. Select [Monitor] in Service Mode of Tuner box.
2. Press [OK] button on the remote control.
5.1.2.2. How to enter into Service Mode of the Display unit
While pressing [VOLUME ( - )] button of the Display unit, press [0] button of the remote control three times within 2 seconds.
Service mode of the Display unit sees section 5.2.
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