I have a UK SP50L7HX (HLP5085W in rest of world I think!), it is approx 3 years old.
I have been experiencing a prob where the screen goes completely black after a random amount of time (seems to go blank much faster if input is high def ?).
I have purchased and replaced an original lamp (from discount merchant), and everything seems ok for a couple hours, then it did it again. As I said, it seems to go blank quicker with high def input.
so, i am sure lamp is ok, as it is brand new, when the screen goes blank the sound remains, and there is no errors. also, looking to the back, the lamp is still lit?
I have run the tv without covers (with lamp cover taped down) and a desk fan running FAST to try and see if the tv was overheating, but it still happens (I assume that the temp cut off would shut the whole tv down, or at least the lamp?, but my lamp stays lit).
Any ideas, it's driving us nuts! the tv has been hoovered out etc to remove any dust (wasn't much).
I am thinking ballast? but would a faulty ballast not turn the lamp off completetly, rather that just stop light reaching the screen?
Also, I have managed to watch the tv on Standard Def for a whole night without issue, but on high def the screen goes blank everytime (5 mins to 2 hours ??) so this confuses me more :-(