I have just checked in the PG50 manual.. it describes the entering of service mode as I described in the other post. I haven't actually tried this for myself as I don't have a PG50.. but I know it works on other similar Panasonic TVs.
If you like I can send you a PDF file service manual for this model. I don't normally offer to do this so don't tell anyone!

(it's a 2.6MB file)
Here's the official way to do it according to the TX32PG50 manual...
Set BASS to MAXIMUM then :
Set the TREBLE to MINIMUM then exit sound menu by pressing the SOUND menu button again. (Don't press
N )
Press
- / v on the FRONT of the TV WHILE
pressing the
INDEX button on the remote - PRESS TOGETHER
if it doesn't work,
try again ., it can take a few goes to make iit enter the service mode. If this doesn't work.. then I guess the PG manual is wrong!
You are in the service mode.
use the RED and GREEN buttons to navigate through all the available options like H Pos and V Pos etc... pick what you want to alter then use the YELLOW or BLUE to adjust.. MAKE SURE you note the original value before altering incase you balls it up... YOU MUST STORE each new adjustment after by pressing the STR button on the remote.
If mess up a value, DON'T store it, and it will revert to the previous value. you have to store every new adjustment you make. so SLOWLY adjust what you need then store when happy.
DO NOT ALTER any of these options : DVCO, Cut off DC, Ug2 test,Highlight lowlight or Sub brightness ...
To exit service mode, press N and then turn off completely for 20 seconds. (mains off) then power up and check it out, press N to restore the user settings to normal.