Many radio amateurs are switching from EMPRA, making homemade electronic ballast for fluorescent daylight sources. The diagram of the electronic ballast with the oscillograms measured at the control points is shown in the figure:
The figure below shows the oscillogram at the time of starting (lighting) the fluorescent lamp, as well as a drawing of the printed circuit board and the appearance of the electronic ballast.
Ballast printed circuit board, its appearance and oscillogram at the time of starting the lamp
In the video below, the master who made this electronic ballast indicates the main features of the hand-made manufacture of this device:
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Already during the beginning of the mass operation of fluorescent lamps, radio amateurs learned to extend their service life and forced fluorescent lamps to light up, in which the incandescent filaments had burned out. Ignition was provided by increasing voltage applied to the lamp electrodes.
The voltage increase is carried out according to the scheme with a full-wave multiplier on diodes and capacitors. Thus, at the moment of start-up, a voltage peak of more than 1000 V is reached at the lamp electrodes, which is sufficient for cold ionization of mercury vapor and a discharge in the gas of the bulb.Therefore, ignition and stable operation of the lamp is possible, even with burnt-out spirals.
The ratings of the lamp starter components are shown in the table below.
The main disadvantage of this circuit for starting fluorescent lamps is the high rated voltage of the capacitors - at least 600 V which makes the device quite bulky. Another disadvantage is direct current, due to which mercury vapor will accumulate near the anode, so the lamp will need to be switched periodically by removing it from the holders and wrapping it.
The resistor acts as a current limiting function, otherwise the lamp may explode. The resistor can be wound with your own hands using nichrome wire, but the same results are obtained with a properly selected incandescent lamp, in which the dissipated thermal energy will not be wasted, but will be emitted in the form of an additional glow of the light bulb.
In most cases, radio amateurs use a 127 V incandescent lamp with a power of 25-150 W instead of a resistor, combining them if necessary. The power of the lamp connected instead of the resistor must be several times higher than the power of the connected fluorescent lamp. The ratings of other elements, calculated based on the power of the fluorescent lamp, are shown in the table.
Ratings of components of the device for starting burned-out fluorescent lamps
In this table, the required resistance and power of the diffusing lamp is achieved by connecting several 127 V bulbs in parallel. The diodes can be replaced with imported ones with similar characteristics. Capacitors must withstand a voltage of at least 600 V.
Fluorescent lamps are widespread and are successfully replacing incandescent bulbs. Fluorescent lamps are technically complex and sometimes fail. Since such lamps are quite expensive, the repair of fluorescent lamps becomes relevant for many consumers.
A fluorescent lamp is a gas-discharge light source in which a discharge of electricity in mercury vapor produces ultraviolet radiation. Due to exposure to ultraviolet radiation with the help of a phosphor, a glow appears.
The principle of operation of the luminaire is shown in the diagram below:
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.
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.
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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 faulty 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.
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 adapted to extend the 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 increase in voltage 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.
Before searching for a breakdown, make sure that there is voltage, there may be no voltage and there is a reason that the fluorescent lamp does not light up. If this is not the reason, we look for it in this order.
turn on the light and nothing happens;
the bulb glows only at the edges;
the light is flashing with a strobe;
the starter is on and the lamp does not start.
Please note that manufacturers recommend replacing fluorescent lamps and starters at the same time.
she flashes a strobe;
the edges of the flask are black;
it glows, but the brightness is not enough (it shines weakly);
the lamp does not work.
A typical breakdown of budget luminaires is destruction of lamp holders and loss of contact. High temperature of a closed luminaire, the cause of destruction of plastic fasteners and connectors. Replace them if possible, bend the contacts if the condition is satisfactory.
A possible malfunction is a burnout of the choke, often this breakdown is visible visually, a changed color, a melted terminal.
If you do find a malfunction, you will have to replace the choke with a working one to repair the lamp. You can check the performance with a multimeter, the resistance of a serviceable one, in the order of 30-40 ohms. Make sure the choke is not short-circuited before placing the lamp in an inoperative lamp. Otherwise, you will lose a worker too.
Sometimes there is a breakdown in the wires - the vibration of the lamp breaks off a core near the lamp holder or choke. In this case, repairing a fluorescent lamp is reduced to restoring contact. The owners of the old-style lamps bypassed these malfunctions.
If you have a lamp with electronic ballasts made in china and replacing the light bulb did not solve the problem, most likely the problem is in the electronic unit. In most cases, you can fix it yourself with a soldering iron and a multimeter at your disposal. Below we will take a closer look at how to repair the electronic ballast of a fluorescent lamp with your own hands.
Now we will look at the main malfunctions that can be eliminated without much investment. Let's start with electronic ballast, because in its circuit there are a lot of elements that can fail, and besides, tubular fluorescent lamps with electronic ballasts are more common today.
The most common failure is transistor breakdown. This breakdown can only be determined by removing the transistors from the circuit and checking them with a tester. Overall transistor junction resistance
400-700 Ohm.Burning out, the transistor pulls a resistor in the base circuit with a nominal value of 30 ohms.
There is also a fuse or a low-resistance 2-5 Ohm resistor on the board, most likely it will have to be replaced, which will end the repair. You may additionally have to change the diode bridge or its elements.
Rarely is the breakdown of 47n film capacitors (microfarad floor) or a resonance capacitor in the filament circuit. There have been cases when all of the above is intact and in good order, but the lamp does not work, the reason lies in the DB3 dinistor. If you checked all the elements of the circuit, then try replacing the dinistor.
Perhaps you decide that it will be cheaper to buy a new electronic ballast than to repair a broken one. Replacing the starting equipment should not be difficult, because the connection diagram is applied to the device itself. Upon close examination, it is easy to understand, L and N are terminals for connecting to a 220V network.
We also recommend watching a video that clearly shows how to repair the electronic ballast of a fluorescent lamp yourself:
VIDEO We draw your attention to the fact that this technology can also be used to repair the CFL energy-saving light bulb. For example, if one heating burned out, the repair is the following procedure:
VIDEO If your old-style lamp does not light up and you are sure that the reason lies precisely in it, the first thing we recommend is to check the starter. The easiest way to check is with a working starter with the same characteristics on hand. However, if no suitable replacement device is available, then a functional test can be carried out using an incandescent bulb with a socket. Everything is quite simple - we connect one wire from the cartridge directly to the outlet, and the second through the starter, as shown in the photo below:
If the light is off, then the reason is in it. Instructions for replacing the starter of a fluorescent lamp are clearly provided in the video:
VIDEO The choke can be checked with a multimeter by ringing its winding. If the choke is really out of order, then the repair of the fluorescent lamp comes down to the fact that you just need to change the choke for a whole one.
Here are the main malfunctions that I personally encountered and successfully eliminated. Following our algorithm, troubleshooting will take a little time and returning the lamp to work on its own will be a couple of trifles. We hope our DIY fluorescent lamp repair instructions were clear and useful for you! Be sure to watch the video tutorials, because they go over in detail all the steps to fix a broken light bulb.
It will be interesting to read:
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In this article I will tell you the common breakdowns of modern "ballasts" of fluorescent lamps, how to repair them, I will give analogs of radio components that can be used for repair. Because These lamps are still quite common in everyday life (for example, I use 5 such lamps every day), I think the topic is more than relevant.
If your fluorescent lamp has stopped shining, the first step is to replace the fluorescent "bulb" itself. It may have two malfunctions: failure of one of the channels (breakage of the heating coil) or the banal "aging" effect.
If in the dark on a switched-on lamp there is a barely noticeable glow of the filaments, then, most likely, the breakdown of the electronic "ballast" consists in the breakdown of the capacitor connecting the filaments (see Fig. Item 2). Its capacity is 4.7n, working voltage is 1.2kV. It is better to replace it with the same one, only with an operating voltage of 2kV. In cheap ballasts there are 400 or even 250V capacitors. They are the first to fail.
When the actions from the previous paragraph did not help, you need to start checking the radio components with the fuse in the diagram. It is often available, but I do not have it on the board (see Fig. Item 1).
The next thing to pay attention to is transistors (see fig. Item 1).They can fail due to power surges, for example, if there is a relay voltage stabilizer at home, or often you or your neighbors use welding. These replacement transistors can be found in power supply units for energy saving lamps. Because such lamps often fail due to bulb breakdowns, then the circuit and, accordingly, the transistors, remain working.
If there are no such lamps, then you can replace the transistors with analogs. Analogs of transistors 13001, 13003, 13005, 13007, 13009 are shown in the table below. The most popular replacements are analogs such as KT8164A and KT872A.
Sometimes you need to ring the rest of the radio components and replace them, if damaged are found. After each stage of repairing the ballast of fluorescent lamps, it is recommended to turn them on for the first time through a 40-watt incandescent lamp connected in series. By its glow, you can see the presence of a short circuit.
It is important to remember that modern electronic ballasts are impulse devices, which are strictly prohibited to be switched on without load (in our case, a fluorescent lamp), because this will lead to their failure.
Video (click to play).
If you have tried everything, but nothing has helped, or there is no desire to tinker with the ballast, then you can use a switching power supply from an energy-saving lamp. It is so small that it fits easily in some fluorescent lamp housings. In this case, the filaments of the fluorescent lamp are connected to the contacts on the board, where the contacts of the bulb of the energy-saving lamp were connected. The wattage of the power supply should approximately match the wattage of the lamp. Personally, I have a 36W fluorescent lamp powered by a power supply from a 32W lamp.
