Yesterday I was turning off the ceiling fan in my daughter's bedroom (it's a fan - light combo but only the fan was on; fan and light are controlled by separate wall switches) and when I flipped the switch off I heard a fairly loud "pop" and I think I saw a brief flash of light from near the fan housing. My wife said she has heard a pop once or twice in the past also. I have not turned on the fan since and plan on taking it down to inspect it but I wondered if anyone had any thoughts on a possible cause.

The pop has only happened when switching it off and never switching it on?

Yes, we only noticed it when switching the fan off.

What make and model is the fan?

Does it still function as it should?