IMPORTANT : Before you throw a screen away because you think beyond repair, ask before budget in an electronic workshop , it may be a small thing (every day are cheaper and sometimes costs more to repair, but still not worth more than a new repair, convenient repair, you are recycling, less waste and investing in local labor).
In this case I was left a screen which two seconds to light the lamps emitting a like a very low "zzzzz" buzzing sound turned off. The sound was probably the vibration of capacitors stage transformation frequency of 50 Hz which is the AC, that being in poor condition that sound emitted.