No power, red led doesn't light. Power cord is

If you've already tried resetting the TV to factory settings and replacing the Power Supply/LED Driver board, the next step would be to check the power cord itself. Here are a few steps you can take to troubleshoot the power cord:

1. Make sure the power cord is securely plugged in: Check that the power cord is plugged in firmly to both the TV and the wall outlet.
2. Check the power outlet: Plug another device into the same outlet to make sure it's not a problem with the outlet itself.
3. Check the power cord for damage: Inspect the power cord for any visible damage, such as frayed or broken wires. If you see any damage, replace the power cord.
4. Check the voltage output: Use a multimeter to check the voltage output of the power cord. The voltage output should match the voltage listed on the TV's specifications.

If the power cord appears to be damaged or not functioning properly, you can try replacing it with a new one. If none of these steps resolve the issue, it may be a problem with the TV's internal components and you should consider contacting Samsung support or a qualified technician for further assistance.

Do you have the panel out? You said all the backlights work, were you able to see them all light with your tester? If so I'd lean towards main board issues. On most larger Funai brand sets one shorted lamp will shut down the inverter from over current.

Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis.
http://electronicshelponline.blogspot.com/
To some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement. To some models sets, the back-light inverter and SMPS section circuit will be integrated at its main board itself. If so; the main board should be replaced. To some models of sets, all these section circuit will be integrated at its main board. If this is the case, you have to replace the main board.

Make sure the cord is pushed in all the way on the back of the tv. If it is then check for fuses on the power supply board inside the tv

Now tv turn on have power LED and OPC LED lights indications flashes together?Yes,this problems,it is the tv Tuner signal board it is causes and the problems.That the board where the incomming broadcasting signal cable plug into it.If turn tv on.No power LED light or any kind LED lights at all.Yes.Than the tv power supply board that the cause and the problems,that the board where the tv power a/c cord plug into it.U have some basic mechanicals skills like take things aparts and putting it back together again?Yes,tries websites like Shopjimmy.com,Ebay.com to buy a whole refurbish tv Tuner signal board or tv power supply board for the replacement.

Tries tv unplug,replug it back like about an hour later.By letting the tv resetting itself back to the factory setting.Now,the tv should be working again,if the tv still getting same result no power LED light indication at all or just flashing power LED light indication.Mean ur tv the power supply board is the causes and the problems.The power supply board,that board where the power a/c cord plug into it.Tries websites like Shopjimmy.com,Ebay.com to buy a refurbish power supply board for the replacement.

U check the power source?Yes,than the power supply board is the problems and the causes.That the board,where the power a/c cord plug into it.Tries websites like Shopjimmy.com,Ebay.com to buy a whole refurbish power supply board for the replacement.

bad main pcb

If the power supply outputs are good! Then I would say the back light inverter is bad! If the screen stays black and does not come on.