An Easy Guide to Flourescent Light Fixture Repair

by DoItYourself Staff

Fluorescent light is more energy efficient than incandescent lighting. The biggest drawback is that very often it is not working as seamlessly as incandescent lighting. However, the problem is usually fairly simple to repair. Below are the four major problems associated with fluorescent lighting and their causes and solutions.

No Light

Cause: Fluorescent bulbs do not generally quit working in the way an incandescent bulb does by just burning out. Therefore, the problem typically is because there is a problem with the electrical connection.

Solution: Replace the starter first. If that does not solve the problem, replace the ballast.

How to Replace the Starter: A starter is used in some fluorescent lights to preheat the cathodes with the glow from a starter. Unlike with bulbs, starters have no outward appearance of whether they are good or bad. To replace a faulty starter, remove the tube, twist out the old starter, and twist in a new starter. The starter is located at the end of the light fixture and looks like a small can.

Partial Light

Cause: If the ends light up but the center does not, it is probably the starter. If the ends are blackening, the tube is probably beginning to fail. Dimming uniformly may mean that the tube is beginning to fail, or is dirty.

Solution: Replace the starter if the ends light up, but the center does not. Replace the tube if the ends are blackening or there is overall dimming. Before replacing the tube, try cleaning it to see if that fixes the problem if there is overall dimming.

Flickering Light

Cause: Tubes often blink when they are brand new, at temperatures below 50 degrees F, and just before they go out.

Solution: If any of the above situations is happening, first check to make sure the tube and the starter are properly in place. If that does not solve the problem replace the tube.

Humming Sound or Bad Odor

Cause: A humming sound or a noxious odor when your fluorescent lights are on indicates that there is probably something wrong with the ballast.

Solution: First try to repair by tightening the ballast. If this does not solve the problem, replace the ballast.

How to Replace the Ballast: Turn the light off at the switch and at the circuit breaker. To get to the ballast, pull off cover by locating and turning the metal tabs. Locate the ballast (there may be two if you have four bulbs in your fixture). Remove the wire nuts connected to the ballast. If the wires are not connected with wire nuts you will need to cut the wires and reconnect once new ballast is installed with wire nuts. Unscrew the ballast and carefully remove by sliding it off. Replace ballast with like ballast from your local hardware or lighting store. Replace new ballast by reversing the above directions. Reinstall bulbs and turn circuit breaker and switch back on. If this does not solve the problem, you may need to replace the entire fixture.