Antwoord op "Where is a decoder for diagnostic LED pattern?"For People trying to locate diagnostic LEDs on Imac 20" EMC:2082. They are located under the right speaker box.It's a large white plastic box in lower right corner behind the front panel and black plastic wrapping. You must remove the single screw holding it in and then wiggle it out of its surroundings. I came accross this thread searching for how to do this, so I thought this would be a good place to put the information.