I need to pull my light bulb to inspect it and determine if the bulb is bad or something else is going on. I know from many of th threads that there should be a set screw at the top of the ring/niche to remove to pull the fixture from the niche. However I have thoroughly checked and can not find a set screw. I have posted pictures. The fixture seems to be secured at the top but moves back and forth at the bottom of the niche.