Tv is on, screen is black. Sound is working. Channels won't change. Tv will not turn off.

it's the inverter. you can get one here. tvtechparts com

The rectangle is the set or the box if used in the closed caption area is set or TEXT is selected--turn that off.

Won't change channels: up or down? Direct enter a channel with the remote 03 and enter to see if it works that way.

Also need to know if you are using a box for signal.

Resolve the text issue first so you can clearly see the regular screen.

Let me know what happens and what you have tried.

may have some loose connection inside the tv occur, or a tv circuit problem already

LCD's use a colorful crystal see through display which only visible when light is shining through it. if you have sound and no picture it's always a faulty PSU. Very easy to change out actually.

Ur backlight video inverter board is dead,need a new board.

Normal 0 false false false MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} It seems there is a loose connection between the board producing the picture and the screen; this is why this would happen. If turning the TV on and off makes no difference, try contact Phillips to see if they can talk you through a factory reset. If this does not work, the set may require service.

I had the same problem once with my RCA television. It only happened on certain channels and didn't happen during commercial breaks. If I adjusted the volume on the tv the box went away, but came back shortly after. The problem ended up being some malfunction in the closed captioning. I turned it all off and changed the CC settings and never had the problem again.