What is the most common problems that occur in Seiki tv model # SE50FY10 when the screen does not turn on but the power light is on?

Back - light problem. 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://electro-medical.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.

Back - light problem.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.

Back - light problem. 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://electro-medical.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

Look for the ballast board. It will have a ribbon cable from the power supply board and has several transformer looking devices mounted on it . This board controls the white back light for the TV. You can get it repaired or replaced from here:

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.

Check for bad inverter board responsible for the back lighting so you can see pic.

This is an exact problem that I am facing with my Seiki 50" TV. From my research, here are the probable issues:
1. Main Board/T-Con Boards are fine
2. Power Board : MIP550D-5TB could be defective - most probably the culprit. There is a power test to try but w/o schematics, it is not possible to identify component
3. If Power Board replacement does not solve, it is the backlight LED strips that are defective - tought one to replace.
Will update this thread at a later date.

Back - light problem. 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/
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.

Do the flashlight test from the video below.
I'm having similar problem, the backlight is not working, I'm trying to find how to replace/repair it.