Tube light circuit is shown above which consists of following components:-
1. Tube Rod
3. Ballast (Choke)
4. Power supply
There are following problems that occur in tube lights and how to repair them are also discussed below:-
Faults in Tube Lights
Tube Light Starting Problem
While switching on the Tube light if light doesn't flicks and even not turned ON then there is very chances that supply isn't coming in tube light so check for the supply at supply end.If this does not help, try wiggling the tube gently in its sockets by rocking it back and forth and from side to side. This will scour away minute deposits of corrosion or dust that can sometimes hinder the flow of electricity. Be sure to do this when the light switch is turned off.
It is normal for the light in new fluorescent tubes to flicker or appear to swirl in the first 100 hours of operation.
If an older tube exhibits these symptoms, turn off the switch, remove the tube, then clean the ends thoroughly. Socket shapes vary, but the tube-removal process is the same.
Replacing Tube Light
To remove a straight fluorescent tube, rotate it a quarter-turn in either direction and pull the tube straight down out of the sockets. If the tube is circular, simply unsnap it from the brackets supporting it and pull it free from the single socket.
To clean the ends of a tube, scrub the pins projecting from them with fine-grit sandpaper, then wipe away all dust with a cloth or paper towel. If any pins are bent, squeeze them gently with needle-nose pliers to straighten them.
When inspecting the ends, examine the glass portions. A brownish tint is normal on tubes that have been in use for some time. Tubes whose ends are blackened usually are wearing out.
If only one end of a tube appears blackened, reverse the tube end-for-end and reinstall it after cleaning the pins. If the tube is blackened only along one side, rotate it after cleaning and reinstall it so that the blackened portion is turned 180 degrees from its former position.
Tubes that are blackened at both ends still may last a considerable time. So, if a tube still malfunctions after you have cleaned and repositioned it, check the condition of other components of the light before shopping for a replacement tube.
The first component to check is the starter. This is a small cylinder, approximately 2 inches long and usually silver colored. Its purpose is to accumulate current briefly when the light is switched on and then release it after the tube is lighted.
The starter is responsible for the momentary delay in lighting when some fluorescent tubes are switched on. If it is faulty, it can also be the cause of initial flickering as the tube warms up, or of failure to light at all.
Not all fluorescent lights have starters, but if yours does, it will usually be located near a tube socket.
Lights with more than one tube have a separate starter for each. If you do not find a starter, unplug the light or shut off the power, then remove the deflector above the tube and look there, or disassemble the base if the light is a desk or floor model.
To remove a starter, press it inward and twist it counterclockwise a quarter turn; it should pop out.
There is no way to tell if it is malfunctioning except by replacing it, and since starters are available at hardware stores for less than a dollar, it is worth the gamble. Take the old part with you to obtain a duplicate.
Fluorescent lights designed without starters are called rapid-starting lights, and this designation is usually printed or stamped on them. With these, dirt on the tube can sometimes prevent lighting or can cause flickering.
The cure is to remove the tube and clean it by wiping it first with a cloth dipped in dish detergent, and then with a cloth dipped in plain water. Be careful when handling tubes; they are fragile and if smashed may explode into shards.
If a fluorescent tube blinks on and off-a slower and more distinct process than flickering-the fault may lie in loose wiring or in another component, called the ballast. The ballast is almost always to blame if the fixture hums during operation.
To inspect the wiring and ballast, remove the deflector or disassemble the base, as well as any other parts necessary to expose the tube sockets and wiring.
Check that the plastic twist-on connectors joining the wires are firmly tightened and that the ground wire (usually green) is fastened tightly to the metal body of the fixture. No exposed wires should be present.
A wire that appears disconnected probably is, and should be reconnected. The sockets, as well as other components, should also be firmly fixed in place.
The ballast is a rectangular metal or plastic component resembling a small box with wires issuing from both ends. To test it, install a working fluorescent tube and a new starter. If the light malfunctions, the ballast is at fault and must be replaced.
Mark the ballast wires and the wires leading to the socket with pieces of tape so that they are paired to simplify reinstallation, then unfasten the wires from their connectors and unscrew the ballast from the fixture.
Take the ballast to a hardware or electrical supply store when you need a replacement.
If replacing both the starter and the tube did not make the light work and the wiring was intact, then the problem is definitely in the ballast. If noise is the only problem, get a low-noise ballast, which is clearly marked as such. If the light is operated in temperatures below 50 degrees Fahrenehit
(another cause of blinking and flickering), obtain a low-temperature ballast.
When shopping for a new fluorescent tube, compare lumens (brightness), wattage and life expectancy. Most manufacturers print this information on the cartons. Bulbs typically last for at least a year, often much longer.
It is worth noting that the life expectancy of tubes is based on the number of times the tube is started. Because tubes consume greater amounts of electricity during starting, it is actually best to leave fluorescent lights burning rather than turn them on and off at frequent intervals.