To test fluorescent bulbs, start by checking your electrical panel box to confirm the circuit isn't broken. With a CFL, is there any way to tell if a bulb is bad without plugging it into a socket and trying it out? If the bulb still does not light, the gas may have leaked out and the bulb will need to be replaced. A dead fluorescent can be caused by lack of electrical power (tripped breaker or blown fuse), a dead or dying ballast, a dead starter or a dead bulb(s). Install a new ballast, if necessary. You will usually … You can buy 4-lamp electronic ballasts, and you should be paying well over $15 for a ballast unless you're getting the $2-3 new-stock pulls off ebay, which is my preference. They’re fragile and have potential to break into shards. Loading... Autoplay When autoplay is enabled, a suggested video will automatically play next. And they're supposed to last 22 years or somesuch. We know ads can be annoying, but they’re what allow us to make all of wikiHow available for free. % of people told us that this article helped them. If the darkness only forms on one end of a tube light, flip the tube so the darkened end is on the opposite side of the fixture. Bulbs are the most common problem with a bad fluorescent fixture. And they're just as bright, if not brighter. Photo 1 shows how to tell if a fluorescent bulb is bad and how to replace it. Look at the end of the bulb for a dark area; if you see one, the bulb is either bad or going bad. Step 3. The burned fluorescent bulb has a darker end of it. Identifying the viability of a fluorescent bulb is somewhat more complicated. On this site, we will refer to the fluorescent lights as lamps. You can also use a multimeter to determine if the electrodes still hold conductivity. Using a digital multimeter to test the bulb; 1. Many of us don’t pay attention to our light bulbs until they burn out and when they do, it can be difficult to know exactly which size, shape or style you need to replace the bulb in your fitting exactly. A dead fluorescent can be caused by lack of electrical power (tripped breaker or blown fuse), a dead or dying ballast, a dead starter or a dead bulb(s). When all else fails, the ballast should be replaced. And a burned fluorescent bulb can not light up anymore. How can I check the starter of a tube light? How do you easily tell if a CFL bulb is bad? Knowing the type of fluorescent light you will use with your ballast is a good start to your search. While they may still light, they are wearing out and will die soon. Check if the bulb is working in another lamp; 5. Place the probes on both pins of the tube light to get an accurate reading. It's generally easy to tell when an incandescent bulb has burned out. Include your email address to get a message when this question is answered. In incandescent bulbs, you can shake the bulb or look at the filament to tell if a bulb is dead without having to put it in a socket. Check for power first then the starter (if applicable) and then the bulbs. I just replaced the ceiling lights in our kitchen -- 65W standard bulbs replaced by 9W LEDs. If there are black rings in the glass nearest the plastic body then the bulb has blown. Check to see if the bulb is tight in the socket. Scrub the rust and the dust at the holders; 6. References. Another common … How To Measure Fluorescent Tubes. They can be generally divided as compact fluorescents or fluorescent tubes. You must test the fluorescent bulb before considering a replacement. If they appear darkened this indicates the bulb is burned out. Only use lightbulbs that are the proper style and voltage rating for your ballast. She holds a Bachelor of Arts from Luther College and a Master of Fine Arts from the University of Idaho, both in stage design and painting. Make sure the lamp is plugged into a functioning electrical outlet, and then check for damage to the bulb itself. If you really can’t stand to see another ad again, then please consider supporting our work with a contribution to wikiHow. wikiHow's. Light bulb manufacturers use the term “lamp” when referring to fluorescent lights. Step 1. Regardless of whether you're looking to use retrofit or ballast compatible LED tubes in your existing fluorescent fixtures, you'll need to know what kind of ballast your fixture has. Check your circuit breaker box and confirm that the corresponding breaker is firmly in the "on" position. Remove one of the working tubes from another fixture and replace it with the suspect tube. Change out the fluorescent bulb with a new one. You can easily tell if a fluorescent bulb is burned or not. Check the ends of the tube. http://articles.chicagotribune.com/1988-09-23/entertainment/8802010971_1_tube-fluorescent-sockets, https://www.naturalhandyman.com/iip/infelectrical/inffluor.html, https://sciencing.com/why-do-fluorescent-lights-flicker-5031263.html, consider supporting our work with a contribution to wikiHow. Check if the connecting pins are broken or bent; 4. When researching your fluorescent bulbs, pay attention to attributes that will help you narrow your options down. All of these lamps use the same technology as linear fluorescent tubes but are wrapped into shapes which make them more suitable for smaller spaces. When bulbs age and have been used for a long time, brown spots will appear. I don't have a lot of faith in the $10-tier LED replacement "tubes", and their CRI is not up to where real fluorescent tubes are. Look for dark areas at the base of the bulb. 'FB' or 'FU' indicate that the bulb is 'bent' or 'U-shaped,' depending on the bulb manufacturer. If you’re armed with a tape measure, here’s a table to show you how to interoperate the length and diameter of your … Please help us continue to provide you with our trusted how-to guides and videos for free by whitelisting wikiHow on your ad blocker. LEDS in and of themselves are much more efficient than fluorescent bulbs. Unlike fluorescent tubes, LEDs don’t require a ballast to regulate current. Before removing a broken bulb from a socket, power to the bulb needs to be turned off. If darkness forms on one side of the tube, rotate the tube by 180 degrees from how it used to sit. Note the wattage of the bulb to ensure the correct starter is purchased. Do not let go of the tube while working with it in the fixture, especially when rotating it. So, if you see a darker tone on the ends of the bulb or the tube, that means the bulb has been burned off. Replace the ballast cover on the fluorescent light fixture. Replace the bulb with the same size bulb. Check the light bulb first to see if it has burned out. wikiHow's Content Management Team carefully monitors the work from our editorial staff to ensure that each article is backed by trusted research and meets our high quality standards. If the bulb is the source of the problem, it will not light at all. Be careful handling a fluorescent tube. Set your multimeter to test the resistance between the two pins Inspect the bulb and replace it if you see burned or blackened spots. Sometimes light bulbs do shatter when they fail. Rotate the tube in the fixture if the bulb is not darkened on either end. Her theatrical designs, puppet design and construction have been featured in "Theatre Design & Technology" magazine and she has written numerous articles for various websites. Fluorescent light bulbs typically last many years, but when one flickers on and off, or the end turns light gray to black in color, you'll just need replacement light bulbs. When using direct fit LEDs, the ballast is still using energy and eating into your possible energy savings. Let’s show you how to tell if a fluorescent bulb is bad. Gabrielle Black has been a professional writer, artist and designer since 2002. If the fluorescent bulb fails to come on, turn the switch off. If you are interested I can tell you more about tungsten light bulbs and old style wire fuses. What do you do next? Tubes can fall out of a fixture if not properly installed. If it has a distinct odour of burnt electronics, then the bulb has blown. If there is significant yellowed staining of the plastic at the vent where the two glass tubes enter the base then the bulb has blown. By signing up you are agreeing to receive emails according to our privacy policy. What we call a "good burn" for a fluorescent lamp, is one that has lived it's normal life, based on published hours of operation, and is that BOTH ends of the lamp are blackened, or grayed with burn rings. Time will tell. If there is no reading on the multimeter, the bulbs should be replaced. When light bulbs shatter as the failure mode then there has probably been a power surge. Thanks to all authors for creating a page that has been read 52,369 times. If testing tube lights, be sure to test both bulbs even if only one is out. Flip the switch and wait a few seconds. Check for power first then the starter (if applicable) and then the bulbs. Before going out to purchase a new bulb, ensure the bulb is the main problem. If so, replace the bulb. The constant on-off flow of electricity can sometimes loosen a light bulb in the socket. Well, first you need to find out if power is actually getting to the light socket. Testing to see if it is good or bad. Simply look at the filament to see if it is broken, or give the bulb a gentle shake to listen for the familiar "tinkle tinkle" of the broken filament in the bulb. Bring the bulb vent close to your nose and smell. How to Tell If Fluorescent Bulbs Are Blown? By checking for surface-level issues, cleaning the parts, and looking at the electronics, you can determine whether you have an easy fix or a trip to the hardware store. Step 2. Electricians usually refer to a light bulb as a lamp. Step 1. If that happens, the Environment Protection Agency recommends airing out the location of the breakage, then picking up the pieces with a damp paper cloth. Replace it with a fresh one. Turn the fluorescent bulb clockwise to see if it's firmly seated in the socket. Last Updated: March 29, 2019 Turn the fluorescent bulb clockwise to see if it's firmly seated in the socket. If darkness begins to form at the ends of the tube, the bulb may be near its end. Another possible code in this position is 'FC' which would mean that the bulb is a fluorescent circular bulb. A dead fluorescent can be caused by lack of electrical power (tripped breaker or blown fuse), a dead or dying ballast, a dead starter or a dead bulb (s). Lamp Type. A bulb/lamp that blows the filament due to a short (such as caused by moisture) will have much more noticeable black scorch inside the quartz lamp near the blown filament. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/8\/83\/Test-Fluorescent-Bulbs-Step-1.jpg\/v4-460px-Test-Fluorescent-Bulbs-Step-1.jpg","bigUrl":"\/images\/thumb\/8\/83\/Test-Fluorescent-Bulbs-Step-1.jpg\/aid9822564-v4-728px-Test-Fluorescent-Bulbs-Step-1.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"