20" Automatically dimms down?!

[irock101]

Hey,

I am using a 20" cinema display on my macbook air right now. It works fine, but every 3-4 minutes the brightness dimms down dramatically and i basically have to turn it on and off again to get the full brightness again. The white dot on the display keeps blinking as well.
Other then that the display works flawlessly and has so for years. Any ideas how i can fix that? Its really annoying.

Thanks in advance

 

[irock101]

Error code on the LED flash is short, short, long - so its the backlight error - anything i can do to fix this myself?