tv is shut down after 3 second

[thefixer]

this tv broke my head .its chasis EW62B.having proccessor tda12020PQ/n3.I think it is LG as this chasis is put by a fixer inside anoder model.after connecting it to power it is STBY so when pushing PROg button i can here THT after 3 second it is shut down.all volatges are ok i mean 110 v etc. any one to help me with this .thanks in advance