Increase the TREBLE fiture to maximum , Press and hold on the TV F, -/V & INDEX on your panasonic LCD Remote control.
Factory mode will eppear on the screen and you may change the factory settings default to your personal settings.
To select the parrameter press channel up or channel down and change the value press volume up or volume down.
Save and exit press menu on remote control and shut off the LCD TV.
To avoid serious damage please do not enter service mode by untrained person. Call Panasonic Cervice Center.