I see a service manual listed. You'll want that to see it's diagnostic tree.
After more than 8 years trouble free, my hln507 stopped displaying a picture. The light is on, but it will show horizontal lines and nothing else. A couple of times it fixed itself after turning it off for a day.
I tried different inputs (dvi from cable and component from dvd player) with no change. menu works.
Question: lamp? color wheel? or dmd board, i.e., new tv?
I'm very sorry for any inconvenience this may have caused you. Unfortunately, this sounds like it may need servicing. Here's the thread where you can get details on setting that up: http://forums.cnet.com/7723-13973_102-542437/service-issues-click-here-for-help/
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