Television and Home Theater

Sometimes when I turn to a channel on my television(RCA) I get a black square covering the majority of the screen. I was assuming it was a block. So I went to the menu and checked the settings, all types of ratings were unblocked. Yet, the black square is still there! Any suggestions?

Hi my dad recently got a free 51WS510 tv with the 8 blinking lights. After getting a service manual and reading aruond I have come to the conclusion that the fly back transformer needs to be replaced. Would it be better to just replace the Dboard or is the flyback transformer plug and play (no soldering required). I don't have any electronic circuit board soldering experience so I'm not reallly tempted to do any of that.  Could some tell me how I can safely perform swapping D boards or replacing the flyback transformer if its an easy task.

Alas, I am having this problem with my old CS-2710 27" CRT TV when these problems that cropped up yesterday:

1) I have no video or audio in internal tuner mode.

2) When I switch my TV to line input mode I hear the audio from the VCR connected to the TV.

3) I can still hear the slight "buzz" through the TV's internal speakers when it's powered on.