Do-it-yourself fluorescent lamp repair

In detail: DIY repair of a fluorescent lamp from a real master for the site my.housecope.com.

Low power fluorescent lamps are successfully used in the illumination of the desktop in the kitchen, flowers on the windowsill or an aquarium with fish.
But they, like all imperfect devices, are not devoid of flaws and may one day simply break down.
This article will briefly describe the process of disassembling, diagnosing and repairing one of these devices.
The luminaire presented for renovation has a 13W fluorescent lamp.

Its body itself consists of a plastic molded body, in the form of a square profile, an electronic ballast, two sockets for installing contacts in them, a lamp and a switch.

The problem is that when the power is connected, the working lamp and the switch is turned on, the lamp does not work.

First you need to remove the socket from the side of the switch.

To do this, use a screwdriver to pry and raise the edge of the plastic case, releasing the socket latch.

At the same time, we pull the outlet to the side, until it comes out of the latch. Be careful not to cut the wires going to the network connector.

Now, having removed the insulating tubes from the soldering of the connector, you can check with a multimeter whether the voltage is coming to the luminaire.

If there is voltage, proceed to checking the switch. Usually it is not done very well, therefore it requires mandatory verification.
To pull the switch out, pry its rim with a screwdriver and pull it evenly on both sides, pull it out.

Two wires are connected to it. To check the operation of the switch, in parallel with these wires, we connect the dial tone and click the power key.

Video (click to play).

If the circuit appears when turned on, then the switch is working. If there is no circuit, we solder the wires and short-circuit them.

We install the lamp and apply voltage. If the lamp does not glow, remove it and continue disassembling.
On the opposite side, we also remove the socket in the manner described above and unsolder the wires from the connector. Otherwise, you will not be able to get to the "insides" of the lamp.

Now we pull on the first socket, and the wires with the board come out of the case to the outside.

If everything is fine visually, the wire is not broken off anywhere, then the only solution to the problem is to replace the board. It can be purchased at wiring stores or on the radio market. The cost of such a board can cost three times less than the cost of a new lamp, so replacement makes sense.

The main thing is to choose a board for the same power as it was. There are launch boards of much higher quality than those that are originally in the lamp, therefore, replacing it, the device's performance can last for several more years.

When unsoldering the wires, you should mark where, which ones were. You can take a photo of the board with the wires, which will guarantee the correct connection later.

Having soldered the new electronics, we assemble the lamp in the reverse order. Having checked the operability, we solder the wires to the connector and the switch. Next, we finally assemble the lamp.
That's all. Successful repairs to you.

Video of the cause of the malfunction of the fluorescent lamp

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Numerical designations in the diagram:

stabilizer (ballast);
lamp tube (includes electrodes, gas medium and phosphor);
phosphor layer;
starter contacts;
electrodes;
starter cylinder;
bimetallic plate;
flask filler (inert gas);
filaments .;
ultraviolet radiation;
breakdown.

Note! A phosphor layer is required to convert ultraviolet radiation. By changing the composition of the layer, you can get the desired shade of light.

Read also: DIY ball screw repair

The main element of a fluorescent lamp is a ballast. There are electromagnetic (EMPRA) and electronic (ECG) ballasts. In the electromagnetic ballast there is a choke and a starter, and in an electronic device, functionality is provided due to the operation of electronic elements.

Most of the breakdowns of the luminaire are associated with the failure of some components of the electronic circuit, aging, wear and tear of the light bulb itself. Repairing fluorescent lamps begins with identifying the cause that led to the problem.

Standard incandescent bulbs burn out instantly and completely unexpectedly. Fluorescent lamps wear out gradually. The light source starts blinking when turned on. This symptom indicates a change in the chemical composition of the glowing gas (degeneration of mercury vapor) and speaks of burnout of the electrodes.

A blinking fluorescent light usually has a blackening of carbon deposits on the end. The phenomenon arises as a result of a burnt-out spiral and running processes of a chemical nature in the inner part of the flask. It is impossible to repair such a lamp to the state of a new product, however, it is quite possible to extend its service life.

The flashing of the luminaire is also possible as a result of a malfunction of the electronic ballast or electronic ballast. In this case, you will need to replace the lamp to determine the breakdown.

You do not need to throw away the light bulb. There are regulations according to which fluorescent light sources must be disposed of according to certain rules, since there is mercury vapor inside the fluorescent lamp.

Another reason not to throw away your fluorescent lamp is that even if the filaments are burnt out, the lifespan of the device can be extended. Repair work consists in soldering some elements of the luminaire or connecting it to an electronic ballast using a cold start method.

In some cases, even the work lamp starts flashing during switching on due to a number of negative events, such as interruption of the starter chain when the sinusoid is at zero. In such a situation, the induction voltage jump is not enough for the process of ionization of the gaseous medium in the flask.

Blinking occurs at the start due to insufficient voltage in the mains. During operation, there should be no blinking, since the ballast keeps the current at a given level.

We repair the flashing lighting device in the following sequence:

We check the voltage in the power supply and the quality of the contacts.
We change the light bulb to a working one.
If the lamp continues to blink, change the starter in the EMPRA lamps, check the throttle. In the case of electronic ballasts, you will need to repair or replace the electronic ballast.

To carry out repair work, you will need a certain set of tools, including a soldering iron, a multimeter, and screwdrivers. It is very good if, in addition to the tool, you have at least a basic set of knowledge in electrical engineering.

To repair a device with an electronic ballast, perform the following steps:

We check the capacitors. They are used to reduce electromagnetic interference and compensate for the lack of reactive power. In some cases, the malfunction is associated with leakage current in the capacitors. This cause must be eliminated first to avoid unnecessary replacement of a sufficiently expensive capacitor.
We call the electromagnetic ballast to find a breakdown. If the multimeter has an option for measuring inductance, we look for an interturn short circuit according to the characteristics of the choke. Do-it-yourself rewinding of ballast is not worth the time spent - it is a very time-consuming operation. In this regard, it is easier to change the ballast or install an electronic analogue. The necessary electronic ballast can be bought in a store or taken out of a broken lamp.

Electronic ballast circuits differ depending on the manufacturer. However, the principle of their operation is no different from each other: the filaments are characterized by a certain inductance, which makes it possible to use them in a self-oscillating circuit. The circuit includes capacitors and coils, has feedback with an inverter, consisting of powerful transistor switches.

When the threads are heated, their resistance increases, the vibration parameters change. The reaction of the inverter is to supply voltage to light the bulb. The voltage on the filaments is shunted by a current through the ionized gaseous medium, as a result of which the heating is reduced. The feedback of an inverter with a self-oscillating circuit makes it possible to control the current in the light bulb.

A diode rectifier equipped with a filtering and suppression system is used to power the inverter. High frequency inverter is one of the reasons why electronic ballasts are in high demand among consumers. Such a lamp does not flash with a doubled mains frequency of 100 Hz, it works almost silently (unlike an electronic ballast).

To diagnose the state of electronic ballasts in a workshop, an oscilloscope, frequency generator or other measuring equipment is used. If the repair is carried out at home, the search for the problem is carried out by visual inspection of the electronic board and sequential search for the damaged component using the available measuring devices.

First, we check the fuse (if any). A broken fuse is often the cause of a lamp failure. This happens in the event of a power surge. The fuse is blown due to improper operation of the ballast.

The cause of a malfunction can be almost any element of the ballast, including a capacitor, resistor, transistor, diodes, chokes and transformers. Blackening of electronic components due to burn-in indicates a problem.

The performance of the system is checked with a multimeter. For the check to be of high quality, it is recommended to disassemble the system into parts by desoldering the necessary components from the board. When parts are placed together, false measurement results are possible. Without watering, reliable indicators can be obtained only for breakdown.Advice! When testing system elements, problems with their identification often appear. In this regard, it is recommended to acquire a device diagram even before starting the repair.Defective parts found should be replaced. Soldering semiconductors (diodes and transistors) must be done very carefully, as these components easily fail after overheating.Note! It is not permissible to start the electronic ballast without load. First, connect a fluorescent light bulb of suitable power to the ballast.If the lamp does not light up due to a failed starter and it is not possible to replace it, it is recommended to use a non-starter switch. In case of failure of the throttle, there is the possibility of throttle-free switching. Let's take a closer look at these ways to fix the inclusion problem.A connection diagram without a choke is shown in the picture below. The method is rather complicated; knowledge in the field of electrical engineering is required for implementation. Image - DIY fluorescent lamp repair

The voltage is applied following a short circuit in the filament. After rectification, the voltage increases by 2 times, which is more than enough to start the light bulb. Thus, switching is performed without the use of a choke.

Capacitors C1 and C2 are taken at 600 V, for capacitors C3 and C4 you need a voltage rating of 1000 V. After a certain period of time, mercury vapor will settle on one of the electrodes, the light will dim a little (or the lamp will stop lighting up altogether). To get out of the situation, it is enough to change the polarity, that is, to unfold the recovered fluorescent lamp.

There are luminaires on sale that work exclusively without the use of a starter. Such devices are marked with the abbreviation RS. If such a lamp is placed on a luminaire equipped with a starter, it will burn out very quickly. The reason is that this lamp takes more time to warm up the coil.The service life of the starter is short, the mechanism often breaks down. Therefore, it would be practical to consider turning on a fluorescent light without a starter. The starterless wiring diagram is shown in the following figure.

At the very beginning of the mass operation of fluorescent lamps, radio amateurs have adapted to extend the service life of burned-out devices. The inclusion of such light sources was ensured by increasing the voltage directed to the electrodes of the lamp.

The voltage increase is carried out according to a scheme in which a full-wave multiplier on capacitors and diodes is involved. Thanks to this approach, when the lamp is turned on, there is a voltage peak exceeding 1000 V. This is enough to carry out cold ionization of mercury vapor and create a discharge in the gaseous medium of the flask. As a result, it becomes possible to ignite and stable glow of a fluorescent lamp even with a burnt-out spiral.

The main disadvantage of the circuit is the too high voltage rating of the capacitors, which should not be less than 600 V. Such a high voltage makes the device too bulky. Another disadvantage is the use of direct current, in connection with which mercury vapor accumulates near the anode. For this reason, the light bulb needs to be switched from time to time by removing it from the holders and turning it.

The resistor acts as a current limiter, otherwise rupture of the light bulb cannot be avoided. The resistor can be wound by hand. This will require a nichrome wire.

Instead of a resistor, 127 V incandescent bulbs and a power of 25 to 150 W are most often used. It is necessary that the power of the luminaire used instead of the resistor be significantly higher than the power of the fluorescent lamp.

The ratings for the other components calculated with the fluorescent lamp wattage are shown in the following table:

According to the data given in the table, the resistance and power of the diffusing light bulb occurs due to the parallel connection of several 127 V light sources. It is best to replace diodes with imported products with similar parameters. As for capacitors, they must operate at a voltage of at least 600 V.

Fluorescent lamps (abbreviated as LDS) have occupied a worthy niche in the electric lighting market due to their efficiency and high performance.

Various modifications of LDS have appeared, which make it possible to improve lamp starting devices (electronic ballasts), minimize the size of lamps, make compact fluorescent lamps (CLS) by combining a bulb and an electrical board in one housing.

These lighting electrical appliances are significantly more expensive than conventional incandescent bulbs, therefore, if fluorescent lamps fail, you should think about their repair and restoration.

The principle of operation of fluorescent light sources, their connection and replacement are described in detail in the previous article, and you can learn about the types, advantages and benefits of fluorescent energy-saving lamps by clicking on this link. Here, the main problems of fluorescent lamps, methods of extending the service life of the LDS and the possibility of repairing ballasts (ballasts) will be described.

It is worth briefly describing the interaction of the components of a fluorescent lamp - the lamp itself cannot work without a ballast, which is electromagnetic (EMPRA) in the form of a throttle and a starter, and electronic (Electronic ballast), in which the physical conditions for the launch and glow of the light source are provided by electronic components.

Osram electronic ballast for fluorescent luminaires

Accordingly, the cause of an inoperative lamp can be malfunctions, both in the electronic circuit of the ballast, and aging, wear and tear of the lamp itself.Correct determination of the reasons will allow you to repair an idle fluorescent lamp with your own hands.

Unlike conventional incandescent bulbs, which stop working (burn out) instantly and always unexpectedly, the rapid wear of a fluorescent lamp can be determined by how it blinks (blinks) during startup. This process indicates changes in the chemical composition of the glowing gas (degeneration of mercury vapor) as well as the burnout of the electrodes.

Very often the fluorescent lamp blinks due to malfunctions in the electronic ballast or electronic ballast. Replacing the lamp with a new one will help pinpoint the cause of the blinkingBut don't throw away your old lamp. First, it must be disposed of in accordance with state laws, as there are harmful mercury vapors inside the flask.Secondly, even if the filaments are burned out, you can extend the operating lines of this light source using a simple circuit that you can solder with your own hands, or by connecting the lamp to an electronic ballast with a cold start, closing the contact terminals, as shown in the video:

Replacing a lamp as the easiest way to diagnose a luminaire

Checking and repairing ballasts, as well as extending the life of a worn-out lamp, requires radio engineering knowledge and appropriate tools, such as a multimeter, a soldering iron, a set of screwdrivers, etc.

Since a fluorescent lamp with an electronic ballast is quite simple, after replacing the lamp and starter, the repair algorithm consists of the following steps:

Check capacitors that are used to reduce electromagnetic interference and compensate for reactive power losses. Sometimes, although rarely, the fluorescent lamp blinks due to current leaks in faulty capacitors, so it is worth excluding this cause before changing the relatively expensive choke.

Chokes for fluorescent luminaires

Electronic circuits differ for different manufacturers of electronic ballasts, but, in general, their principle of operation is the same - the filaments of fluorescent lamps have a certain inductance, which allows them to be included in an auto-oscillating circuit consisting of capacitors and coils. This circuit has a feedback with an inverter assembled on powerful transistor switches.Typical circuit of an electronic ballast for two fluorescent lampsWhen the filaments are heated, their resistance increases, the characteristics of the oscillations change, to which the inverter reacts, giving out the lamp ignition voltage. The current through the ionized gas shunts the voltage across the filaments, reducing their glow. The feedback of an inverter with a self-oscillating circuit allows you to adjust the current in the lamp.A diode rectifier with a filtering and noise reduction system is used to power the inverter. The high-frequency inverter is one of the reasons for the great popularity of electronic ballasts - the connected lamp does not blink at twice the mains frequency of 100 Hz, and does not hum during operation, as is the case when using electronic ballasts.

This eliminates the likelihood of flickering. The last stage is a high-voltage pulse. The luminescent lamp is ignited in 1.7 s. If a failure occurs when the light source is started, the filament body instantly breaks down (burns out). Then you can try to do the repair yourself, for which you need to open the case. The electronic ballast circuit looks like this:

The main elements of the electronic ballast of a fluorescent lamp: filters; directly the rectifier itself; converter; throttle. The circuit also provides protection against power surges, which eliminates the need for repairs for this reason. And, in addition, the ballast for discharge lamps implements the function of power factor correction.

For the intended purpose, the following types of electronic ballasts are found:

for linear lamps;
ballast built into the design of compact fluorescent light sources.

Electronic ballasts for fluorescent lamps are divided into groups that differ in functionality: analog; digital; standard.

The ballast is connected on the one hand to the power source, on the other - to the lighting element. It is necessary to provide for the possibility of installing and fixing electronic ballasts. Connection is made in accordance with the polarity of the wires. If you plan to install two lamps through a ballast, the parallel connection option is used.

The diagram will look like this:

A group of gas-discharge fluorescent lamps cannot work normally without a ballast. Its electronic design provides a soft, but at the same time almost instantaneous start of the light source, which further extends its service life.

The ignition and maintenance of the functioning of the lamp is carried out in three stages: the heating of the electrodes, the appearance of radiation as a result of a high-voltage pulse, the maintenance of combustion is carried out by means of a constant supply of a small voltage.

If there are problems in the operation of gas discharge lamps (flickering, lack of glow), you can make repairs yourself. But first you need to understand what the problem is: the ballast or the lighting element. To check the operation of the electronic ballast, a linear lamp is removed from the luminaires, the electrodes are closed, and a conventional incandescent lamp is connected. If it lights up, the problem is not with the ballast.

Otherwise, you need to look for the cause of the breakdown inside the ballast. To determine the malfunction of fluorescent lamps, it is necessary to "ring" all the elements in turn. You should start with the fuse. If one of the circuit nodes is out of order, it is necessary to replace it with an analogue. The parameters can be seen on the burnt element. Repairing HID ballast requires the use of soldering iron skills.

If everything is in order with the fuse, then the capacitor and diodes that are installed in close proximity to it should be checked for serviceability. The capacitor voltage should not be below a certain threshold (this value differs for different elements). If all the control gear elements are in working order, without visible damage and the ringing also gave nothing, it remains to check the choke winding.

In some cases, it is easier to buy a new lamp. It is advisable to do this in the case when the cost of individual elements is higher than the expected limit or in the absence of sufficient skills in the soldering process.

Repair of compact fluorescent lamps is carried out according to a similar principle: first, the case is disassembled; the filaments are checked, the cause of the breakdown on the control gear board is determined. There are often situations where the ballast is completely functional and the filaments are burned out. In this case, it is difficult to repair the lamp. If there is another broken light source of a similar model in the house, but with an intact incandescent body, you can combine the two products into one.

Thus, the electronic ballast represents a group of improved devices that ensure the efficient operation of fluorescent lamps. If the light source flickers or does not turn on at all, checking the ballast and then repairing it will extend the life of the light bulb.

This article describes the possible causes of a fluorescent lamp breakdown and its repair.

Electronic ballast - this little plastic box, and this is actually all that is inside (well, except for the wires, of course).

We open the electronic ballast and here it is the board (the heart of our lamp), then we will repair it.

An ordinary pulse converter is an electronic ballast, which is made according to a well-known traditional scheme, for this reason this scheme is not presented.

First, we check the fuse F, if it is working - we look further, if it is out of order - change it and see further.
Check the electrolytic capacitor (shown as C1 in the photo above) and installed diodes near it. If the capacitor is out of order, replace it with an analog, 6.8 uF x 400 V. Diodes of the 1N4007 type.
Check capacitor C2. This is one of the weak points in this circuit, it is considered weak most likely due to the use of a low-quality Chinese capacitor here. Here it was changed to a 4700 x 2kV capacitor (see the photo below).
Ring all the remaining semiconductor elements, if something is out of order - change it, if everything is normal - check the choke winding again, if it works too - change dinistor D.

Well, that's all. Keep in mind that there are times when repairs can cost more than the cost of a new lamp, so if this is the case, then don't torture yourself, it's easier to buy a new one.

If you did everything right, then this lamp will still serve you.

Before repairing, it is better to first check the operability of the LDS itself, since it may be that the lamp itself is out of order, and this is possible not only because of the incandescence (check, of course, just in case), but maybe the lamp is simply old.
When you replace the lamp, turn it on in complete darkness, if you can see a weak glow of the incandescence, then this is most likely the reason for the failure of the capacitor C2, in which case you can try to change it first, and if this does not help, then follow the entire sequence of steps outlined above.
In the case of a "difficult" repair, check all ballast elements. This is a general tip for repairing impulse circuits.
It is advisable to turn on the lamp for the first time by turning on a conventional incandescent lamp with a power of 40-60 W.
Also, as in any other impulse devices, it is necessary to avoid connecting the ballast without load, otherwise its breakdown is practically guaranteed.