how do i fix technika tv/dvd combi sc500172?

my technika tv/dvd combi wont turn on from standby some times it will turn on when power has been on ie in standby for 2 day but most times it will stay on standby, WHEN it does turn on every thing works perfectly but when it is turned off in sandby or at the mains chances are next time it is used it will once again not come out of standby either using remote or tv buttons please help it is only 18mths old THANK YOU IN ADVANCE