Q. I replaced one tube in a two-tube incandescent light fixture. Both tubes now are very dim and flicker constantly. Any suggestions on why and how to fix it?
A. Always replace all the bulbs in a fluorescent fixture at the same time, even if only one is having trouble.
Q. Do 4-foot fluorescent fixtures come in different wattages?
A. Yes, the most common are 25-, 34-, and 40-watt bulbs.
Q. What makes the tubes in my fluorescent light flicker?
A. Wiggle the tubes to make sure they are properly seated. Replace any tubes that are dark or have damaged pins. Replace the starter if there is one.
Q. How do I troubleshoot a fluorescent fixture that doesn't light?
A. It's probably not the bulb, because these rarely go bad all at once. Check for adequate ground. Wiggle the tube make sure it is seated. Replace any damage lamp holders. Replace the starter. Check the switch and outlet box to make sure it is getting power.
Q. What's causing my fluorescent fixture's hum?
A. The ballast vibrates. Lighten or possibly replace with a higher sound factor. Another sign of a faulty ballast is black tar-like substance oozing from the fixture.
Q. How do I check the starter in the fluorescent fixture?
A. Older, delayed-start "preheat" fluorescent lights flicker when they first light up. If this lasts more than a couple of seconds, make sure the starter is seated by pushing it in and turning clockwise. If the ends of the tube light up and the middle does not, the starter is bad. Remove it by turning counterclockwise.
Q. The tubes in my fluorescent light are graying near the ends. Does this mean they are wearing out?
A. Working tubes usually have a gray tinge on the ends, but dark gray or black is a sign that the tube is failing.
Q. My fluorescent fixture does not seem to be putting out as much light as it used to. Could the tube be failing?
A. If the entire tube is dim, it may simply need washing. Try removing it and wiping it with a damp cloth.
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