Why monitor screen upside down?

@christophe25821 try to access the service mode for your TV. On your remote hit

POWER OFF==> MUTE==> 1==> 8==> 2==> POWER ON

if that does not work try

POWER OFF==>INFO==> MENU==> MUTE--> POWER ON

Then under the Options Menu you may have something like MRT Options, select that. There you should find something like HV flip. Give that a try. Some menu options are different due to different firmware version etc. If you can't immediately find it, keep looking for it but do not change any other items.

If your can't fix it with the Service mode then the issue could be a bad EEPROM on your mainboard. Sometimes a reprogrammi of that will fix the inverted screen issue. This will require the exact firmware for your TV mode, which is sometimes hard to find. In those case either a new EEPROM or a new main board should fix it