My skyworth 32E8A has no picture but have sounds. what seems to be the rootcause?

You send it back and ask them to replace it under warranty.
You take it in to a local repairer.
Or you just buy a new one and try not to break the screen by throwing things at it or knocking it over. It is sad as it is a $900 set. :>(

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There are some fixes in the link

https://www.google.com/search?q=skyworth+49E3000+picture+freeze

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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

Take is to a second repairer and ask. The first one may have meant it was not economical to repair or parts not available to repair. Skyworth is not a good make.

Skyworth, officially Skyworth Group Co., Ltd., is a Chinese holding company. Its subsidiaries design, manufacture and sell televisions and other audio-visual products. They also invest in properties. Wikipedia

Here is some information on self repair

https://www.fixya.com/support/r29790007-repairing_own_television

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Sounds like a failed led or led backlight. Some googling will point you towards replacement parts.

Check the speaker/s first. If found OK; check and replace the damaged component/s at its audio output section circuit board. If needy, 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. Surf the site with patience.
http://electronicshelponline.blogspot.com/

are you using vga or hdmi? you may need a separate audio cable.

Check its back-light inverter board, and CCFL lamps.

try check the connection of the wires or try to check if you lock the mute button..

spurious oscillation in video circuit