Projector noise question

Hello. I recently purchased a used 2300mp projector and when I shut it down I notice it's making a slight crackle or popping sound. It makes the noise right after the fan turns off during the shutdown process. None of the orange or warning lights come on to say it needs a new bulb but, I'm wondering if this is normal or indication of a problem? I would appreciate any advice so I can make a decision on wether or not I need to return the projector and try to get my money back.Thank you.