LG PLASMA TV turns on then right off!

This is an lg plasma I found, and am wishing to repair it. I have soem basic knowledge of electromics and have already taken it apart and didnt find any visible damage(also tried resoldering some weird joins). The tv clicks, goes on to turn on but when it comes to sctually start it shuts right off. I know this is not a motherboard issue since I tried the disgnostics screen color test and same thing happened (where you discommect the motherboard and short two points with a jumper wire) any recomendations on what to try next? Thanks

This is an LG 50PK350, dating back to 2010/10