I have the same unit that's worked flawlessly for the past 10 years....until recently, that is. It seems after it runs for a few hours it gets "hot" and decides to cut off until it cools. Leave it alone, and it turns back on all by itself. This is simply a sign of old age and worn resistors, circuits, etc. Obviously, cleaning the inside to remove collected dust won't hurt, but it really won't fix the problem. Inevitably, we're going to have to bite the bullet and purchase a newer receiver.
J Baldridge, December 2008