I have an old HP L1908W 19" LCD used a second display under Windows 7, its connected via a DVI / VGA adapter and started blanking itself after a few mins - there is a sudden increase in brightness and then goes blank as if its powered down but the power light stays on. I've noticed the following... Turning it off and back on will make it work for a few seconds and then it blanks again. The OSD doesn't work when it blanks out. Disconnecting the input cable or disabling the screen when blanked brings up the "no signal - going to sleep" message and reconnecting will make the screen come alive again but again only for a second or so Leaving it powered off for a bit will bring it back to life again so I'm guess bad capacitors or similar as its a 12 year old screen but before it gets pulled apart is there anything else to check for?
Quick update... Pulled it apart and cant see anything physically wrong, none of the caps are bulging or leaking and nothing looks burnt or damaged - guess its back on ebay for another dirt cheap screen lol