Hi,
the problem is that the lamps of the back lighting system are ignited
for a second.
I have changed the elettrolitici condensers and controlled the mosfet.
There is an integrated TL1451AC, it could be out of order?
If it were not possible to repair it, I can change it with an other model?

Regards

Some inverters have a ceramic capacitor across the primary of the
transformer. Usually around 0.1 Uf. I have had a couple of inverter
boards where this capacitor was bad. The set would come on for a second
or two, then go off.
Hope this helps....
John