Model M550VSE. Audio works, but why is video gone?

There could be several reasons why your Vizio TV goes black after being turned on, including a malfunctioning power supply, a damaged display panel, or a faulty backlight. Here are some steps you can take to troubleshoot the problem:

1. Check the power supply: Make sure that the TV is properly plugged in and that the power outlet is working. You may also want to try plugging the TV into a different outlet to see if that solves the problem.
2. Check the display panel: If the TV is getting power but there is no picture, the display panel may be damaged. Look for cracks or other signs of physical damage to the screen. If you find any damage, you may need to replace the display panel.
3. Check the backlight: The backlight is responsible for illuminating the screen, and if it is faulty, you may experience the symptoms you described. Look for any signs of damage to the backlight, such as flickering or uneven lighting. If the backlight is the problem, you may need to replace it.
4. Reset the TV: Sometimes resetting the TV to its default settings can solve the problem. To do this, unplug the TV from the power source, wait a few minutes, and then plug it back in.
5. Contact Vizio customer support: If none of these steps solve the problem, you may want to contact Vizio customer support for further assistance. They may be able to provide additional troubleshooting steps or help you arrange for repairs.

Your LED backlights are bad, it's a common failure

Usually backlighting problem. Start from power supply board. Best to get service manual or wiring diagram.

contact any service technician.

Hello Jerry, for what you mention, the problem on your TV Vizio M43-C1, is in the backlighting, some of the LEDs that illuminate the LCD Panel are wrong and that is why you can not see the image
You have to change all the LEDs to do a correct job
I suggest you look for a specialized technical service
I hope you can solve the problem
Greetings Franco Dosil

Hola Jerry, por lo que comentas, el problema en tu TV Vizio M43-C1, esta en la retroiluminacion, alguno de los LED, que iluminan el Panel LCD est?n mal y por eso no se ve la imagen
Hay que cambiar todos los LED para hacer un trabajo correcto
Te sugiero busques un servicio tecnico especializado
Espero puedas solucionar el problema
Saludos Franco Dosil
http://cdn.vizio.com/manuals/kb/m43c1manual.pdf

You might want to check the VIZIO website for help. Given how cheap even 4K UHD TV's are today, probably not worth fixing again. Unless under warranty, of course.

Sounds like a mainboard/Digital board. Might be the panel too. Vizio makes substandard TVs and they tend to fail very easily. As much as I like to see devices repaired, this one may not be worth your hassle. Power problems caused by lightening can be the most damaging. You may even need both power and digital boards to repair it. I would buy boards from someone who will take them back in case the panel failed too.

If there is no video but you have audio or you have intermittent video:

1. Press and hold the mute button on the VIZIO remote for 3 to 5 seconds. Some VIZIO TV's have a "Mute Screen" feature that turns the screen off if you are streaming an audio application (Pandora, Spotify, etc) and don't want the screen on. To activate/deactivate this feature, hold the mute button for 3-5 seconds.
2. Turn the TV off and unplug it. Press the power button on the side of the TV for 30 seconds. Let go of the power button and plug the TV back in.
3. Check the connections between the TV and device. Ensure the cord is connected securely to the TV and the source device.
4. Try a second device. (Example: If the issue happens on a Cable/Satellite box, try using a DVD player or gaming system to see if the issue occurs there.)
   1. If the issue occurs on multiple devices there is an issue with your TV. Please contact Support by Clicking Contact at the bottom of the page or give us a call Monday - Friday from 7am - 11pm Central Time or Sat. & Sun. from 9am to 6pm Central Time at 855-833-3221.
   2. If the issue only occurs on one device the issue is not with the TV but with the device or the cables used to connect it to the TV.

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.

I will try a new main board first.