Light bulb manufacturers use the term “lamp” when referring to fluorescent lights. If you’re armed with a tape measure, here’s a table to show you how to interoperate the length and diameter of your … Up next If you are interested I can tell you more about tungsten light bulbs and old style wire fuses. Last Updated: March 29, 2019 'FB' or 'FU' indicate that the bulb is 'bent' or 'U-shaped,' depending on the bulb manufacturer. Time will tell. Install a new ballast, if necessary. Currents travel between both tubes and either could be causing the problem. Check the ends of the tube. 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. By signing up you are agreeing to receive emails according to our privacy policy. If you’re still unsure your ballast has bit the dust, then you need to get your hands on a brand new bulb. In that case it would be more appropriate to say the bulb has blown. The pieces must be sealed in a plastic bag then thrown away. There are some usual reasons a bulb can go bad, and we can do some quick checks to find out if it’s fixable or a replacement is necessary. Thanks to all authors for creating a page that has been read 52,369 times. To test fluorescent bulbs, start by checking your electrical panel box to confirm the circuit isn't broken. This article was co-authored by our trained team of editors and researchers who validated it for accuracy and comprehensiveness. Be careful handling a fluorescent tube. 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. We use cookies to make wikiHow great. Fluorescent tubes are filled with mercury gas and can shatter into very small pieces. So, if you see a darker tone on the ends of the bulb or the tube, that means the bulb has been burned off. Other Problems That Can Be Identified and Fixed with The Above Checks If testing tube lights, be sure to test both bulbs even if only one is out. Check your circuit breaker box and confirm that the corresponding breaker is firmly in the "on" position. Flip the switch and wait a few seconds. Set your multimeter to test the resistance between the two pins You can also use a multimeter to determine if the electrodes still hold conductivity. wikiHow's. Well, first you need to find out if power is actually getting to the light socket. Gabrielle Black has been a professional writer, artist and designer since 2002. Scrub the rust and the dust at the holders; 6. Bulb vs Lamp. Step 1. If they appear darkened this indicates the bulb is burned out. Or in other words, the lifespan of the fluorescent bulb is over. Rotate the tube in the fixture if the bulb is not darkened on either end. % of people told us that this article helped them. Bulbs are the most common problem with a bad fluorescent fixture. Sometimes light bulbs do shatter when they fail. Look at the end of the bulb for a dark area; if you see one, the bulb is either bad or going bad. If you are installing a tube-style fluorescent bulb, be sure the pins on each end are in contact with the ballast's socket. If you really can’t stand to see another ad again, then please consider supporting our work with a contribution to wikiHow. We know ads can be annoying, but they’re what allow us to make all of wikiHow available for free. Let’s show you how to tell if a fluorescent bulb is bad. If so, replace the bulb. Step 2. Photo 1 shows how to tell if a fluorescent bulb is bad and how to replace it. How to Tell If a Fluorescent Tube Is Bad? 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. The constant on-off flow of electricity can sometimes loosen a light bulb in the socket. How can I check the starter of a tube light? When working with electronics, make sure the power source is off to avoid electric shock. With a CFL, is there any way to tell if a bulb is bad without plugging it into a socket and trying it out? Visually inspect ; 3. When all else fails, the ballast should be replaced. Knowing the type of fluorescent light you will use with your ballast is a good start to your search. If your fluorescent tubes have recently fizzled out – don’t panic. Replace the bulb with the same size bulb. Step 3. 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Lightbulbs that are the proper style and voltage rating for your ballast bent ; 4 clockwise see. The plastic body then the bulbs should be replaced can sometimes loosen a light bulb is 'bent ' or U-shaped.