HDMI input problem with Sony KDL 52XBR4

I'll apologize first if this issue has been covered and I stupidly missed it, or if I should be posting in a different sub forum. I'll apologize as my "problem" seems to be far less serious than others here.

The issue I've come across showed up about a week ago, and has not gotten better nor worse. When I turned the set on to watch a BluRay through my PS3, the image was far lower in contrast, much brighter and less distinct than I am used to. Since I'd watched "Thor" many times with my girls, I was very familiar with how it should look.

I went through the process of elimination. At first I thought it was a bad HDMI cable, either between my PS3 and my Yamaha receiver. Cable swaps made no difference. I was hoping it was the receiver (I've never been happy with the sound through my Boston Acoustics speakers and was dying for an excuse to buy a Denon lol), but sending the output of the receiver to another HDMI input on the Sony TV confirmed the worst- since the images looked their usual fantastic self on HDMI 2, I now knew the problem was somewhere in the set.

Has anyone run into this, and if so, can you please tell me this is a simple, inexpensive issue? I'm hoping for a HDMI jack, or a plug-in board that will be an easy (i.e. non-soldered) swap. In the old days of simpler equipment, I'd have used an eraser or sprayed some contact cleaner in the jack, but I don't have the guts.

The set is only 4 years old, with no extended warranty, and I really can't afford a new one. I know all is not lost, so long as the other inputs work. I really would like a new receiver for the addition of HDMI inputs. The Denon has 6, and between my PS3, Uverse box, AppleTV and Samsung BluRay would put a good dent in those.

As an aside, at first I thought it was some issue with the auto dimming. That has driven me crazy from the beginning with this Sony, and I've never seen any way to turn it off.

Thanks for any help and insight into this annoyance!

I tried changing both the cables (I have several sets) and the same cables in different HDMI receptacles in the set. The results were consistent, even after multiple swaps and reseating. Any set of cables from the receiver to the TV's HDMI1 resulted in a soft, low contrast, too bright picture. The same cables always produced the picture I'd come to expect with this TV.

As I said, I don't know if this is a known issue, or if it's a simple outlet/board swap (it would never be my luck that this could be a modular design.) I am hoping in the worst case, that this is restricted to this single input, and not a sign of a deeper problem.