Is this normal? This light does not have a fan. When it turns on, after a few seconds it will start humming for about 20 - 30 seconds. Is this a symptom of a bigger problem or just normal for this light. I bought it from someone who does not always seem to tell the truth. It should still be under warranty but he also modded (drilled holes on the sides) so that he could hang it using his set up.

