[Resolved]  Sansui / 29" Hard Rock CTV — Power problem

I have a Sansui 29" Hard Rock CTV, purchaged about 03 years back. Problem with the TV is it runs for first few mins and goes off.
Also if swithed on after a moment, runs for few seconds and goes off.
Complianed thrice, also the technician came for attending the complaint, changed some parts but without any result. Even they were also not sure about the problem.
Can you send someone we is expert for handling the problem properly.
Kindly treat the matter on an urgent basis.