Lg tv gray screen main menu screen flickers

no actually not i think you rather shift your choice

Sounds like Back - light problem.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.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. To some models of sets, all these section circuit will be integrated at its main board.If this is the case, you have to replace the main board.

picture board

Hi, the main board of your TV is dead This can be cause by open fuses surface mounted you have to take out the mainboard and check for any open fuses specially from the main processor IC replace if you found any.you can also order a replace board at shoppjimmy.com just follow this link
search for brand and model good luck

The fact that you have no menu or onscreen display, leads me to believe that it is the main logic board. Either the processor ic or the voltages going to the main board are missing. Check to see if the main board is getting 5v and 3.3v to determine if it is your power supply not supplying the voltages or your main board.

Try flipping the main power switch on the back of the TV then the power button

Sounds like a bad bulb.

my problem is don't sound in my mobile LG CE 0168 please help me.

i would check the main total assembly, also you might try unplugging the set for 5 minutes to reset the tv

We had the same problem of pathetic sound quality and volume with a sony brava. Thats just the way they make tv's these days because most people buy a surround sound system as well. We bought logitec computer surround sound speakers for about $140 and plugged into the ear jack, problem solved, we have heaps of volume and stacks of bass.