If your TV turn ON/OFF itself without sounds..The possible problems are voltage drop on power supply,overheat/overload,loose/cold solder of power supply or bad T-con board..
If you already inspected all capacitors on the power supply and all looks fine but it doesn't mean that your power supply board works fine because sometimes bad capacitors not look like bulged or looks fine visually but the value change its either lower/higher capacitance value.In that case you need to use capacitance meter to find bad caps..But before we do that,I have a procedure to minimize/eliminate troubleshooting.In this procedure you need a multimeter tester to perform voltage data check..
In this procedure we can determine where the fault came from..
This are the steps:
- Open the back cover.
- Look at the power supply board (it is usually connected directly to power cord).
3. Find the 3 long connectors near the aluminum heat sink.Those connectors having voltage marks on each pins so you can easily determine where did you get the voltage..
4. Point the black test probe to GND (ground) and the other probe (red) to 5vdc,12vdc/15vdc,24vdc..Let me know if you find any voltage drop or voltage lost..
5. If all voltages are works fine..The possible problem is on T-con/logic board or main board..But in that case the common problems is on T-con board I found it online $34..
Hope it helps..Just keep on touch to fix your TV and works fine again..