LG 42LH20 TV Turn on and off 3 times with picture and sound within about 2 mins then shutdown finally

It was dead and i change a fet, diode, a cap and the 2pcs06 pfc ic.
Then i got 390 vdc but when the back light circuit start and the lamps start working the 390v drop to about 147, this happen 3times in about 2mins then it shot down.