Flickering screen, loud buzzing sound, self boot down.

The cables could either be loose or need to be replaced for your TV or the connection ports are broken. The LED lights or the T conn board could be causing the TV screen to flicker.

Main power supply regulator board can cause this. If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/
Line, faults & possible causes to LCD screen are given with illustrations. You can get an idea about the fault to an extent.

If you wish to get some details; check the site linked here. Pull up older posts. Surf the site with patience. http://electronicshelponline.blogspot.com/
Line, faults & possible causes to LCD screen are given with illustrations. You can get an idea about the fault to an extent.

The controller board for the screen is going bad. check shopjimmy.com for replacement parts. It's not a difficult job to do. Once the back of the TV is removed, you'll see it near the center of the screen.

Resolder all of your boards ,Poor Solder Connections can cause this.

I agree with tom you need to replace all the electrolytic capacitors. It is not that difficult if you know what you are doing. If not take it to a tech savvy friend..

Sounds like maybe color wheel. Does it whine or screetch a bit? That's color wheel.

Probably caused by a power supply nearing its death.
Try to verify this by placing a portable fan to the side of the set with airflow directed at the vented sides.
If this lengthens the operating time, there is a good chance that some minor components in the main supply have developed low values of capacitance and higher losses which worsen with warmth.
Listen closely at the vents with the sound turned down to attempt to detect a squealing sound while the TV is in its failure mode; if you find this, it is also a sign of power supply trying to die.
A tech equipped with a capacitance meter that measures losses at the same time, could find and replace the weakened parts without a whole lot of labor and little cost for parts.

Sounds like the driver board for the backlight is going bad...is there a spot on the screen part of the case ( usually at the bottom) that feels much warmer than the rest?