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What to do with a burnt-out LED spotlight. Repair of LED spotlights. Operating principle of LED spotlight

No one will deny that LED lighting sources such as floodlights are effective in illuminating large spaces. The compactness of the device and the power of the luminous flux, as well as the evenness of the lighting of the space, make LED floodlights popular for private use in country houses. The industry also produces them in the form of portable devices, which is very convenient.

It happens that the device begins to work incorrectly, the spotlight begins to blink, and an even glow occurs. Let's look at how you can fix this problem and the reason for its occurrence.

How does an LED floodlight work?

In order to understand why the LED spotlight blinks, let’s look at how it works and what its design is:

the housing of the LED device can be made of impact-resistant plastic or metal;
There is an LED lamp inside the housing;
reflectors.

The spotlight works on the principle of directing the light flux with the help of reflectors to a certain point, they collect it, for this reason a bright glow is obtained.

The LED, whose task is to provide an even light, consists of a semiconductor element and electrodes, these are the anode and the cathode. When the required voltage appears on the electrodes, they heat up the semiconductor element, and it glows. For the scheme to work you must have:

a special type of rectifier, driver - they must stabilize the current and regulate its value;
power supply for the LED, since it needs 12 volts.

Many breakdowns can be avoided in the future if you pay attention to the following nuances when purchasing:

An LED device is a lighting device with high illumination parameters and low electrical energy consumption. Important! Such systems cannot be cheap if they are well made.
When purchasing an LED spotlight on the Internet, a consumer may encounter various breakdowns that arise due to the cheapness of the models:

after a short interval of operation of the device, the light flux blinks, even when the device is turned off;
The motion sensor supplied with the device stops working.

While trying to achieve cost competitiveness for their devices, manufacturers often neglect quality and reliability; If the spotlight blinks, the following reasons are possible:

bad soldering;
the cheapest batteries and low current control parameters are selected.

As a result of saving materials and reducing the cost of the lighting device, the buyer after a short time experiences problems with its operation. Often, due to the fact that the boundary current is not regulated, the spotlight begins to blink.
There is an opinion that some manufacturers who are focused on Russia install current limiters in their LED devices, without taking into account our regional specifics (frequent fluctuations in electrical energy), which leads to breakdowns.

What are the most common causes of LED spotlight failure?

Not a single perfected device can guarantee operation without breakdowns; there is always a possibility. LED systems, for all their reliability, have frequent malfunctions when LED spotlights flicker. The reasons for this phenomenon always lie in the device itself and its operating conditions.

Motion Sensor

When a motion sensor is purchased in conjunction with a spotlight, and the light flux blinks when supplied, the reasons may be the following:

Incorrect setting of the motion sensor itself - because of this, the LED spotlight blinks. It is necessary to correctly set the timer in the sensor; it is this that keeps the LED system in working condition for the set time; you need to check whether the device is working properly; When all manipulations have been completed, we check the system in operation;
faulty, floating contact - when the sensor is triggered, but the signal from it does not pass to the spotlight. It is necessary to check all internal switching wires, inspect them for integrity, tighten all contacts secured with a screw connection;
the motion sensor has been faulty since the moment of purchase - this problem cannot be solved on your own, you must return the product to the store and ask for it to be replaced;

The motion sensor is continuously under current load and part of it passes to the LED spotlight - a small amount of voltage on the spotlight will not be able to turn it on to full light, but will cause a blinking effect.

Weather

A malfunction in the form of blinking LED spotlights when it’s frosty outside also occurs with popular suppliers of LED devices. The reason for this phenomenon is the appearance of icing on the elements responsible for the LED glow. This phenomenon begins to manifest itself at a temperature of –10 degrees, despite the fact that the technical specifications indicate the operating temperature of the device from –50 to +50 degrees. These parameters are correct, but only for the LED itself, and not for the elements that turn it on.

LED device elements

The solution to this issue is the possibility of bringing the device into the house during the frosty period during daylight hours and taking it back to work at night.

Spotlight mode

Many modern lighting devices have additional modes, and the reason that your LED spotlight is shining may be that this mode is accidentally activated. Experts recommend turning the device off and on and seeing if the glow mode is removed as a result.

In addition, the glow can also be caused by the fact that, in accordance with the design features, several functions are activated by one power button. And by clicking on it twice, you activate the effect of working in strobe mode, as a result of which the LED spotlight blinks.

Lighting in the switch

Very often, LED spotlights are purchased to illuminate the space of a private home, and a backlit switch is used to turn them on.

It is this design of the switch that can flicker at a certain time interval. The reasons for this flickering when the spotlight is turned off are as follows:

the LED in the switch does not completely interrupt the circuit, and the insulated wires play the role of a capacitor, simultaneously performing the task of a conductor in alternating current and its rectifier;
The supplied voltage is enough to start the LED spotlight, but it is not enough to maintain combustion.

It is easy to fix such a breakdown; you need to disconnect the LED in the switch from the power supply or change the switch to a simple design that will work when turned on, and is guaranteed to interrupt the power supply when turned off. Experts also recommend the following to eliminate this type of problem: a capacitance with parameters from 0.1 to 0.5 microfarads must be included in the circuit, as well as a resistance with a power of 2 watts per 50 kOhm, how this can be assembled is shown in the figure below.

Other reasons

Sometimes it happens that all possible reasons for the blinking of the spotlight or its weak flickering have been checked, but it stubbornly continues to do so, what to do in this case? Experts suggest that in this situation, the flickering of the LED spotlight occurs due to induced voltage, which can arise when the main wires going to the spotlight switch pass through the same channel.

To start the LED system, a small voltage is needed, but it is not enough to maintain the glow, which causes the lamp to flicker. In such cases, it is necessary to include in the circuit a ballast having a resistance of about 50–60 kOhm and a power of at least 1 watt.

There is a possibility that after replacing the LED spotlight, the blinking will disappear; this may be due to the quality of the internal switching of the devices, as well as what elements are in the device.

There are cases when the manufacturer of floodlight LED lamps, specifically to improve the brightness of the glow, removes a capacitor from its circuit and increases the value of the limit current, but in this case the matrix of the device is exposed to temperature, the diodes burn out, and the device goes out of stable operation.

The operation of LED systems is greatly influenced by the environment in which the spotlight is operated - at high temperatures, the spotlight may have a dim glow or flicker when the temperature is ten to fifteen degrees below zero. In this case, the cause of the failure is uneven heating or cooling of the driver, which stabilizes the voltage.

Do repairs or buy a new one?

Floodlights do not belong to the category of cheap goods, for this reason even LED systems can be repaired. If you have experience with electrical work, then it is worth disassembling the floodlight system. All lamps can be disassembled, even sealed LED ones.

According to the general opinion of experts, the main culprit for the failure of such floodlight systems to operate normally is a non-working driver. The power supply in the LED system is the weakest point in terms of operational reliability.

In addition, the disadvantage of floodlights of this type is poorly thought out heat dissipation; for this reason, the thermal paste with which the matrix is attached to the board hardens, the light output decreases, and the lamp begins to burn dimly.

If you decide to repair an LED spotlight, you need to select replacement elements for these purposes; they need to match the current and voltage. Sometimes, when selecting parts for replacement, a master can find out for himself what is easier - buying a new spotlight or repairing an old one, since the cost of replacement is slightly less than the cost of a new device.

Conclusion

In conclusion, we emphasize that when the spotlight turns on independently, you need to do the following:

check the device connection;
change the type of switch;
If the spotlight works with a motion sensor, check it for compatibility with the LED device.

Experts pay attention to the fact that the reason for this phenomenon may be the low cost of lighting devices; they do not guarantee long-term operation. When doing repairs, you need to be able to handle a soldering iron, electrical measuring instruments, read connection diagrams and a circuit diagram of the device.

LED floodlights are in great demand among consumers for illuminating shop windows, store facades, courtyards in private homes and other objects. They are durable, have good light intensity and consume much less energy compared to conventional incandescent lamps.

But any equipment has a certain service life and is not guaranteed against breakdowns, therefore it requires repair. It is always cheaper to fix problems yourself than to contact specialists in workshops. Let's look at a simple repair of some faults on LED floodlights, but before describing the repair process, you need to study what types of floodlight designs there are and the principle of their operation.

LED spotlight operation

The voltage from the power source is supplied to the electronic board, the converted current is supplied to the LED element, which emits streams of light. The designs of spotlights may be different, but they all have common elements:

Power supply;
Electronic current and voltage conversion board;
Operating mode control drivers;
Heat sink;
Optical elements, lenses, mirrors built into the body;
Terminals for connecting wires and fixtures for fastening the housing.

Floodlights have LEDs of different sizes and power, but the principle of operation and symptoms of malfunction are common.

Basic spotlight malfunctions

Most often, the malfunction of spotlights is manifested by the following symptoms:

Complete absence of glow when turning on the power;
LED flickering;
Dim glow, not at full power;
Changing the shade of emitted light;

There are obvious signs of deformation of the housing, destruction of the LED structure, after mechanical shocks or breakage, burnt out wiring, which are visible visually.

Main causes of malfunctions

Manufacturers make LED matrices and conversion boards that are reliable and, if used correctly, guarantee a minimum trouble-free period of up to 5 years. Most often, malfunctions occur for the following reasons:

Unstable characteristics of the electrical network, voltage and current surges exceeding the operating mode values;
Short circuit of a phase to the spotlight body or neutral wire;
Incorrect connection;

As a result of these violations, the electronic board on which the floodlight control drivers, voltage and current converters that power the crystal structure of the matrix with LEDs are programmed may fail.

The LED matrix in spotlights can consist of several dozen elements. If the structure of 3-5 crystals in the matrix is destroyed, the spotlight can function, but with a larger number of faulty elements, irreversible processes disrupt the operating mode and all the crystals burn out. In this case, a complete replacement of the matrix is required.

Diagnosing a fault on an LED floodlight

Let's consider identifying a fault on a floodlight, which is in greatest demand among consumers, rectangular in shape with a matrix of 9 diodes, with a power of 10 W. One of the models in this series is the Volpe 10W floodlight with a luminous flux of 750 Lumens.

Regardless of the brand of spotlight, diagnostics begins with a visual inspection:

The integrity of the wiring from the power source is checked, the absence of breaks, burnt insulation and kinks in the cable, where there may be a break in the current-carrying conductor hidden under the insulating layer;
The body of the spotlight and the LED matrix are inspected for absence of deformation, cracks and chips;
If there is no light at all, first of all you need to unscrew the back cover of the case and check the voltage at the input and output of the electronic board of the converter. There should be 220V AC at the input; if there is no voltage, then the reason is not in the spotlight, but in its power supply circuit; measurements can be carried out with a conventional multimeter. The output terminals are 12V DC.

If there is no voltage at the output, the fault should be looked for on the voltage converter board. Inspect the board for oxidized contacts, tin cracks in solder areas and burnt parts;
If there are no signs of malfunction in all of the listed points, the last element remains, this is the LED matrix.

Repair and replacement of faulty elements of LED spotlights

Faults such as broken wires can be resolved quickly and do not require special qualifications. The most difficult repair is identifying a faulty element on the driver circuit board, voltage converter and replacing the LED matrix. Therefore, to make repairs yourself, you must have certain knowledge and practical skills in electrical engineering, be able to read diagrams, use measuring instruments and a soldering iron. If you don’t have such experience, it’s better to turn to specialists.

The simplest way is to replace faulty elements with similar ones; they can be purchased from electrical goods or removed from spotlights on which other parts are faulty. Assemble one working one from two or three faulty ones. A matrix with LED crystals filled with compound material cannot be repaired.

Tip No. 1 If 2-3 diodes out of 9 have burned out in the matrix, then you don’t have to wait for it to burn out completely; this can have a detrimental effect on the drivers and voltage converter. Change the matrix at the first sign of malfunction.

Replacing the spotlight matrix

Unscrew the front cover of the case, which presses the glass;

Unscrew the screws and remove the reflector;

Unsolder and unscrew the faulty matrix;

We solder the new matrix and assemble the spotlight in the reverse order.

Sometimes the wires from the printed circuit board pass to the matrix through holes in the metal substrate, which acts as a heat sink for the matrix. At the transition points, they must be insulated, especially the positive wire, so that there is no short circuit to the housing.

Tip No. 2 When replacing the matrix, wipe its substrate and the surface on which it is screwed. Lubricate these places with heat-conducting paste, only then screw the matrix to the body.

When replacing the matrix, be sure to observe the polarities, the red wire is positive, blue or black is negative, yellow-green is on the body.

If you have a soldering iron and at least the most basic knowledge of radio electronics, then repairing (replacing the driver and/or matrix) an LED spotlight will not be a problem for you.

But it must be borne in mind that based only on an external examination of the faulty spotlight, It is impossible to make an unambiguous conclusion about which part has failed. For example, blinking of the matrix of an LED spotlight can be caused by both a malfunction of the matrix itself and the driver. To accurately determine the source of the problem, diagnostics are needed - at least, you should connect the matrix and the driver of the problematic spotlight in pairs to the same, but known to work driver/matrix.

The main points to pay attention to during the repair process:

correspondence of current-voltage characteristics of the driver and matrix;
the matrix can be installed only for thermal paste;
tightness of the final assembly.

Poorly performed repairs can lead to additional costs. Here is an example - according to the client, the spotlight was repaired four months ago by “craftsmen” from the radio market, who replaced the LED matrix. However, during assembly the seal was broken, and the photographs show the consequences of just four months of street use.

Photos of the insides of the LED spotlight after four months of operation after a poorly made repair - the seal was broken

This spotlight was restored, but in addition to thorough cleaning, it was necessary to change both the driver and the matrix.

One of the modern types of LED light sources for street lighting is an LED floodlight. The electrical circuit of an LED spotlight is not fundamentally different from that of an LED lamp. The main difference lies in their design, since it is required to ensure operability in a wide range of temperatures in precipitation conditions. Therefore, repairing spotlights with your own hands is not much different from repairing LED lamps and is even simpler, since there are no difficulties during disassembly. To gain access to the driver and LEDs of the spotlight, just unscrew a few screws.

Repair of low-power LED floodlight

I received two identical LED spotlights of type SDO01-10 with a power of 10 W for repair. During an external inspection, a malfunction was immediately discovered in one of them - partial peeling of the protective layer and the presence of a dark spot on the light-emitting surface of the LED matrix.

The hope of repairing a spotlight with a faulty LED matrix immediately disappeared, since the cost of such an LED emitter usually exceeds half the cost of the spotlight. And purchasing a new matrix is very problematic, since LEDs usually do not have markings and it is difficult to determine the type of non-standard emitter. The appearance of the second spotlight did not raise any questions.

I decided to simplify the repair task by moving the driver of the spotlight with a burnt-out matrix into a spotlight with a working one. But removing the back covers showed that the drivers in both spotlights were faulty.

In both drivers, the 1 Ohm protective resistors burned out, which indicated a breakdown of one of the diodes of the diode bridge or the key transistor.

Repair of a high-power LED spotlight

Once again I had to deal with the repair of a more powerful spotlight of the SDO01-30 type with a power of 30 W.

The appearance of the spotlight is shown in the photograph. In terms of overall dimensions, it is slightly larger, and the design of the spotlight repeats that of the above presented model.

After removing the back cover from the spotlight and inspecting the appearance of the radio elements on the printed circuit board, no suspicious-looking parts were found.

Inspection of the printed circuit board after its removal from the side of the printed conductors immediately revealed two burnt-out resistors, R8 (2 Ohms) and R22 (1 Ohms). Typically, low-resistance resistors burn out due to the large current flowing through them when semiconductor devices or capacitors break down. Next to the resistors there was a powerful field-effect transistor SVD4N65F, which turned out to be faulty during dialing. The electrical circuit of the spotlight was not available and we had to find out the values of the burnt resistors by opening a working spotlight of the same type.

The faulty resistors and transistor were soldered off and all other semiconductor elements were additionally checked on the printed circuit board. After sealing the working resistors and transistor into the printed circuit board, the spotlight started working.

As you can see, if you have the skills to work with a multimeter and a soldering iron, you can successfully repair any LED spotlights with your own hands.

The repaired spotlight has been working properly for several years. The second one was also recently repaired, thanks to the emergence of a new type of LED matrices, which do not require an additional driver, since it is already installed on the matrix substrate. The matrices are no more expensive than classic products.

In addition, it was possible not only to restore the functionality of the spotlight, but also to increase its power three times, while achieving a zero pulsation coefficient.