Samsung UN46ES6500G E-Manual page 668

Your settings are lost after 30 minutes or
every time the TV is turned off.
If the TV is in the
it will reset audio and picture settings
every 30 minutes. Change the settings
from
mode using the
TV in the
and go to
Store Demo
Source
System
Store Demo
mode to
Setup procedure. Select
using your remote,
→ Setup.
mode,
Home Use