Internal iMac superdrive keeps ejecting discs
The Superdrive on my iMac will not accept any discs. It just immediately ejects discs that I insert. This happened before about a year ago, but I forgot how I got it to work, and I can't find the thread here.
Thus this request: What do I need to do to get the Superdrive on my iMac to work again? I already cleaned it out completely with the air duster. I know that there is some keyboard startup trick or something that needs to be done to reset something, but my brain is aging, and I forgot what it is. Obviously any helpful suggestions will be greatly appreciated. Thanks so much.
iMac, OS X Mavericks (10.9.2), mid-2007 24" 2.4Ghz 4GB RAM