The Panasonic DMR-EX78 DVD Recorder has several disc settings to control disc playback, including a ratings level lock feature to protect children and others from certain viewing material that you have deemed inappropriate. The feature allows you to lock playback of discs that have a certain rating by setting the recorder to that ratings level. Once the feature is set, unlocking it requires that you access the DMR-EX78 "Disc" menu using the recorder's remote control.
Turn on your Panasonic DMR-EX78 DVD Recorder and TV.
Push the "Function Menu" button on your recorder remote.
Press the "Down Arrow" button to highlight "Disc" on the menu. Push the "OK" button.
Highlight "Unlock Recorder" or "Temporary Unlock" on the Disc side menu and push the "OK" button.
Enter your four-digit password when prompted. Follow the onscreen prompts to finish unlocking the recorder as desired.
If you want to change the ratings lock level, select "Change Level" on the menu, enter your password and follow the on-screen prompts.
Selecting "0 Lock All" locks the recorder so that you can't play any DVDs. Selecting "8 No Limit" unlocks the recorder so that you can play discs of any rating.