Hi,
Since it is starting to fail faster over time, and given the rest of your problem discription, i'd say it's some kind of capacitor failing. If this is the case, If you're skillful enough you could desolder the old one and solder an new one for a few bucks. I've seen this many times with Samsung, LG and Philips TV's and monitors. The only way to know that for sure, [guide|6525|you'll need to open up the Cinema Display] .