I have Advent Q2035A model.
Have color problem, that could be called 'chromatic bullseye'. Large center circle drives one color and corners have complementary color...etc. Unplugged set for several hours, fixed it once. But problem recurs.*** any hints and suggestions welcome.
Service mode... I found a way to access SM by chance! In sequence, press Sleep Pic Display Menu. (the general 'thumbing' for the 4 buttons is Left-Rt-Lt-Rt in case your set is diff model)
Once there, 'Menu' toggles 3 pages of factory settings. Modify via Volume buttons. When a single parameter is displayed, hit '9' for selftest. etc etc)
Exit by 'Sleep' when pages are shown.