Power supply (3Y) ticking noise

I replaced the capacitors and when doing a smoke test (nothing connected), I noticed that the power supply makes a soft ticking noise. It's funny because I thought it was the hard drive seek making that noise. I have the 3Y power supply. Anyone have an idea which component is making the noise?

Edit: The frequency of the ticking is 4.3 per second (hmm...60/14?)