I got a Brower THI20. it came with a spare base and got told recently that one of them Blew (Are broken). So i need to find out which one is broken. So I had one plugged in and it sounded like its just the light blub. the other made a louder sound like a clink-clink like if it is turning or something, I need to know please before I decided to hatch. Hope you can help thanks.