HD50LPW175 RCA problem

[ThaiNoodles]

I just recently bought my first HDTV, it is the RCA Scenium HD50LPW175. My problem is that when I use my ps3 with the tv, there is a purple line maybe 2 millimeters thick accross the top of the screen. It is interesting to note that, this is only present when on the ps3 XMB main menu, and while watching netflix. When I have a game booted up, it goes away completely. Is it just because the TV is old, could it be the hdmi cable? Is this the sign of a bigger problem? I'm very new to all of this, any advice would be greatly appreciated. Tried some of the picture settings on the TV but no luck. I'm also wondering if this could be because when me and my girlfriend were trying to carry the tv in the front door, she dropped her side of it from maybe 2 inches off the ground while trying to set it down, but it wasn't a very long fall.

 

[ThaiNoodles]

Also, I should mention that if I tilt the tv backwards a little bit, the line goes away. Could this have something to do with the lamps then? Maybe they got misaligned and just need to be repositioned?

 

[ThaiNoodles]

I've also just found out that this problem does not occur when the TV is hooked up via composite cables as opposed to the HDMI.

 

[ThaiNoodles]

Well after some more tinkering, it seems if I change the PS3 settings from 1080i to 720 p, the problem is completely gone. Can anybody tell me why this is? And is 720 p that much worse than 1080i? I can't spot much of a difference. Any input at all is welcome here.