How do you change a backlight inverter board on a Toshiba 46L5200U TV?

You have bad LED backlight strips, VERY common failure, it amazes me how many people change the power board with no backlights and in most cases it's not the power supply that's bad

usually due to loss of back lighting

Press the TV menu button. If no menu appears the problem could be a bad tcon display board or backlight inverter board. Turn off the room light and check TV for backlight glow. If it has a glow then the problem can be a loose tcon connection or bad tcon board. Check connections.
Or it could be,
Possible TV Back-Light Inverter Board Issue:
To see if the back-light has gone out, turn the TV on. Turn the lights off and make the room dark. Shine a flashlight onto the screen at different angles. If you can see some of the picture then the back-light has gone out. (It should glow a slight grey if it’s working) To fix this you need a TV backlight inverter board. You can buy one online for a relatively low price. Usually the board will have a few bad capacitors on it. You could attempt to repair it yourself if you can identify which capacitor has gone bad. A capacitor kit for a TV board is ultra cheap. You are best off buying the backlight inverter board and installing it yourself. A back-light inverter board should be from $10 to $25 dollars depending on your TV model

As far as picture goes, your backlight leds are not turning on. Your backlight inverter board is defective. Sound is a different board. It could be defective inverter board is pulling down power supply voltages affecting sound board.

You have a problem with the backlight LED`s one or more strips will need replacing not a job for the beginner

T'Con board fault. Check and replace it. If you wish to get some details; check the site linked here. Pull up older posts.
http://electronicshelponline.blogspot.com/

If it's LED or LCD then it's backlights-- just shine flashlight on screen at an angle and see if you can see any movement or bring up menu display and with a flashlight you should be able to see it---as stated above---
Symptom: No picture on screen but LCD TV still has sound.
Solutions: The problem is cause by defective inverter. Replacing inverter will solve the problem---ou cannot see anything at all then it's T-Con board--

Hi Angela,
The backlight system of your TV has failed. Mostly it is the inverter part inside the TV which makes necessary power for the backlights fails. The power/inverter board needs to be repaired or replaced.

Check and replace its back-light inverter board. Contact any service technician. Gopakumar Gopalan Google

If this is an LCD tv the backlight inverter is bad, a good way to check it is to shine a flashlight close to the screen and see if you can see a faint picture.
Let me know what you find

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/jason_77a19afa8d604dee