Panasonic TX-28W3E TV Service Menu

Panasonic TX-28W3E Service Menu mode
Adjust the bass to maximum, treble to minimum
Press RESET on the remote control and while in the TV-VOL. Using the Teletext press RED and GREEN selects the item with Blue and Yellow line values. 
To select parameter press channel up or channel down.
To change the value data press volume up/down. 
To save press menu button
To store the new press STORE. To exit NORM (normalization).

TV Service Menu  Panasonic TX-28W3E