Mitsubishi WD65736 65IN. KEEPS TURNING OFF AFTER STARTUP

I would like to know what the problem may be with my tv. i was told by a tech to replace bubl, which  did, but it didnt fix issue with tv turning off repeatedly. i did the system reset too, nope didnt work. from reading some of the pot asc or isc thing capp something another well i just want to fix my tv without having to pay out the yingyang.  my tv is on now after powering up several times. this is what happens i power it on then 2-15 minutes later it shut off. but here again after 15 times or more today its now staying on, hmm. what is the issue with my tv.