Since 1997, HomeTips has guided millions of homeowners with original, expert advice for DIY home improvement and repair. Founder Don Vandervort, a nationally recognized authority, has written more than 30 books and countless magazine articles, been a host on HGTV, and served as MSN's home improvement expert. MORE
Inside a fluorescent light, electricity is delivered to a ballast, which sends a spark through the mercury-vapor-filled tube (or bulb), creating light by activating phosphors that coat the inside of the tube. If any of the components are faulty, the light won't work right. Once you pinpoint the problem, most fixes are very easy. Remember to turn off the power first!
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An old tube blinks off and on just before it dies; repairs are often simply a matter of replacing it. This problem may also occur because of poor contact between the pins at the ends of a tube and the tube holders. If the pins are bent, use needle-nose pliers to straighten them. Clean the pins and socket contacts with fine sandpaper.
Though gray bands at the ends of tubes are normal, black bands indicate that the tube needs to be replaced. If only one end is dark, turn the bulb end-for-end. If the tube is new and these fixes don't work, you may have to replace the starter or ballast.
Some fixtures ("A-rated") are quieter than others, but most fluorescent lights have a slight hum. If the sound seems too loud--or if you can smell electrical burning--shut off the power. The ballast is probably either the wrong type, improperly installed, or defective. Replace it or call an electrician.
Brand new tubes tend to flicker, as do bulbs that are cold. If an old tube still flickers after it has had a chance to warm up (or after you've warmed up the room), rotate it a couple of times in the tube holders. Try cleaning the tube''s end pins. If it still doesn't work, replace it.
