T-con board or maim Board issue? Disconnected T-con from the main board and got back light! sharp lc-55le55ou

We've seen something similar in our shop on Hisense TV's, and considering Sharp sets are made by Hisence it may be related. The issue we have found was the balling of the prosessor IC was bad, a replacement main may fix it, or you can try "cooking" the board in an oven, see some youtube videos on how to do this

Best bet would be main board, sounds like firmware in EEProm is corrupt

I need help my tv isn’t playing any sound please help!!!

it really depends on were the flicker is, if its the backlight or the screen, flicker can mean them both, t-con board only controls the screen out put on lcds, but on plasmas it works with the back light inverters. if the screen is white and not flickering while looking at the back of the screen on an lcd then it could be the t-con board failing it could also be a bad connection to the board from the wires. the plug were the main board connects to the t-con board if you have the back off and wiggle the cable and see if it stops the flicker.

No. It is back light fault. Check and replace damaged [burned end] CCFL lamp/s. 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/
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.

The main board is having issues eventually the sound will drop out altogether. Replacing the main board should solve the issue. You can get the main board from www.tvrepairworld.com

You will get a white screen when you unplug the t-con from the main board. Doing so removes power to the LCD panel. Verify that all of your voltages from the power supply are correct. If they are, I'd look at the t-con board. It sounds like there is a problem with the t-con that is pulling down the main board.