medion 11ak52b6 plz help

  • the unit is going to start for a second and then off,with front lamp flashing red ,knowing that the unit is building a high voltage for a second ,i checked/replaced all power supply diodes and capacitors (chamical and ceramic) also i changed photocoupler and all the capacitors on the secondary part of power supply ,also changed the main power supply and flyback transistor and the power diodes near the hot!! still have no result