I would start measuring components on the power supply board (yellow). It might just be the angle from which you took the photo but I would start with diode (D15), an the bigger 330uF 25V capacitor above L2 which appears to be bulging slightly. As it is not fully bulged yet, it may cause your intermittent workings of your TV.
Should everything work as it should, I would measure if you get a stable 24V on the connector above CF1.
If the tv works intermittently, it is often harder to diagnose than a completely dead device.