Sony STR-DA3300ES making a clicking sound on powerup?

So I just got in my new receiver, plugged it in and powered it up, and for a few minutes it was making a clicking sound internally...didn't matter which input/output I had it on, it just kept going. After a couple minutes, it just stopped. Haven't had a chance to test more thoroughly, but has anyone had this before with this or any other Sony receivers? I thought it might just be the system warming up, but never heard of this before.

I'm not sure about it. It was the only time it did it, had no sound cutting out during, and after a minute or two, stopped entirely and was on for about 2 hrs while testing.