I replaced the original lamp about 1 year ago when red light came on. A week ago the screen began to get progressivley darker. Screen is still visible and picture quality is fine, just darker. No warning lights on front come on. I ordered a new OEM bulb and installed but no change, picture is still too dark. I reset the lamp hours on both lamp changes. Any suggestions on how to fix? I love the picture quality on this TV and don'want to replace it yet or have to pay for an expensive repair!