LED light sources, due to their qualities and technical characteristics, have gained wide popularity among consumers. However, under the influence of various factors, they, like conventional lamps, periodically fail. Due to the high cost of these products, many home craftsmen are trying to repair LED lamps with their own hands. It should be noted right away that most factory-made lamps cannot be repaired.
Elements of LED light sources
Before disassembling the LED lamp, you should first of all familiarize yourself with its structure and principles of operation. The standard design of such luminaires consists of a power board, a light filter and a housing with a base. In inexpensive budget models of luminaires, current and voltage limitation is carried out using capacitors.
As a light source, LEDs are used in the amount of 50-60 pieces,. The action of these devices can be compared with semiconductor diodes. The movement of current from the anode to the cathode occurs in a straight line, as a result, light fluxes appear inside the LEDs. Each element has a very low power, so they are installed in large quantities in the fixtures. Finally, the luminous flux with the necessary characteristics is created using a phosphor coating.
The voltage supply to the LEDs occurs through a special driver that performs the functions of a converter together with diode groups. First, the voltage is supplied to the transformer, which slows down the operating parameters. At its output, a constant current is formed, which serves as power for the LEDs. An additional capacitor installed in the circuit prevents voltage ripple.
Exist different types LED lamps. However, despite the differences in the device, the number of elements and parts, they have a common design, which greatly facilitates their repair.
Causes of failure of LED lamps
Before repairing the LED lamp, it is recommended to accurately determine the causes of the malfunction. Very often, the service life declared by the manufacturer does not coincide with the real ones. In most cases, low-quality crystals become the cause.
The work of LED lamps is provided Negative influence and other factors:
- They have a negative effect on the elements, most often they provoke malfunctions.
- The lamp is not suitable for this LED lamp. In case of incorrect choice of the ceiling, the lamp may overheat.
- Poor quality of light-emitting elements leads to a quick failure of the luminaire.
- The lighting system itself may be incorrectly mounted, as a result, the electrical wiring is adversely affected.
- The negative impact of a mechanical nature - shock, strong vibration, and so on.
In the event that there are no deformations that can be determined visually, the cause of the lamp failure must be sought with a multimeter or tester.
Among the most common faults that require intervention and repair, problems affecting the capacitor should be noted. To check the performance, you need to unsolder it from the board. After that, as well as the performance of the diodes.
Sometimes the LEDs start blinking. This condition occurs due to a faulty current-limiting capacitor. Another cause of failure is often associated with a burned-out emitter. LED failure is not always visually determined, so you will need to check each part with a tester.
There are standard circuits used to test and repair LED light sources. Most often, after checking with a multimeter, it turns out that it is necessary to replace the capacitor. In this case, the defective part is simply replaced with a new one. The same applies to the driver, when replacing which you should choose the option with the most suitable parameters and technical specifications.
Current-limiting resistors also sometimes fail. Their performance is checked with a multimeter in dial mode. If the indicators deviate by more than 20% from the norm, then the element being checked is faulty. LEDs are more likely to fail. For testing, a battery is used, from which voltage is applied to each LED in turn through a resistor. All defective light bulbs are soldered and replaced with new ones.
Checking and repairing the lamp takes place in a certain order:
- First, the LED lamp must be carefully disassembled.
- Inspect the voltage rectifier for burning, if necessary, it is repaired.
- The next step is to check the capacitor and replace it in case of a malfunction.
- Then the resistors are checked for a break in the internal network.
- It remains to check the performance of the LEDs and replace the faulty elements.
- After replacing the damaged parts, the lamp is returned to its original state. The performance test is carried out by connecting to a standard network, voltage 220V.
When solving the problem of how to repair an LED lamp with your own hands, many are faced with the need to eliminate the blinking of the lamps. This phenomenon extremely harmful to the eyes, so in residential areas the so-called blink rate should not exceed 20%. Higher rates cause serious disorders of the visual apparatus, reduce the speed of thinking and concentration, and lead to increased irritability.
In the event of a constant blinking of the lamp, it is possible to eliminate this malfunction only after the causes of the violation have been clarified. Blinking may appear due to a manufacturing defect, expiration of the service life, incorrect connection to the network, the presence of an LED in the switch. Sometimes it is enough to correctly screw the light bulb into the socket or replace the switch.
There are several ways to fix the problem of blinking on your own:
- Draw a separate line for the lighting fixture.
- Add an incandescent lamp to the circuit to unload the capacitors.
- Adding a resistor to the circuit to compensate for a poor quality capacitor.
It is possible that inside the luminaire or on the line, the contacts have just loosened or there is a short circuit.
Repeatedly came across solutions to automatically turn on lighting in everyday life using external motion sensors. I propose an "easy" version of a similar solution (a couple of options considering concrete examples). It is practically not necessary to have knowledge and skills in electrics (or even worse electronics) - lamps can be used simply “out of the package” ...
I will consider using the example of using it in my country house (where I actually spend most of my time now) and at home.
One of the options the use of LED lamps with a standard type of socles for 220v having a built-in motion sensor combined with a light sensor (I came across another pair of sensors - a light sensor + a sound sensor, probably for toilet use ;).
I bought several of these lamps, for example, I will show both options I ordered ...
I recently made an order - you can buy it much cheaper, but I haven’t seen the fillings of this modification yet (I haven’t received it yet)
One of the lamps arrived relatively recently.
Therefore, I have the opportunity to show how it looks in the package :)
The lamp itself is E27 format, an LED driver is installed in the cartridge.
Next comes a decent-sized aluminum heatsink, only slightly warm during operation. A board with LEDs on an aluminum substrate is screwed on top of the radiator. And already on top is a block with light sensors and IR motion.
Here are two different lamps that I use.
Two lamps for comparison - the left one has already worked for a year on the street in the "always on" mode. Sometimes, with a strong wind, it did not turn off all night. Well, cats turn it on all the time :)
The lamps have different LEDs, but an almost identical block with sensors.
DI broke one lamp for review. this design was not collapsible (we came across earlier in which the driver was available without damaging the design of the lamp)
Here she hung all year (including frosts and rains) - this is the path to the toilet and bath. The arrow indicates where the lamp itself is located. From the place of photographing, the lamp turns on approximately.
Turns on at dusk when a person (or animal) moves. There are no complaints about this lamp at all! I am completely satisfied :) There is a glitch, it does not appear often - if the network is lost, and the lamp appears again, it can “loop” in the on mode, regardless of the time of day. This occasionally happens if the lamp worked very many times (for example, a strong wind all night) - it happens that in the morning it burns - this is quite rare, but it did occur. However, after it becomes lighter, it goes out by itself, and the next night it works “as it should”.
The lamp comes in two shades of glow: warm and cold.
It shines VERY brightly, i.е. for places of recommended use, even with a margin.
There is no flickering (the driver seems to be of decent quality - what we managed to see through the slot). Although flickering (if there were any) in the hallway, on the street and similar places should not somehow strain.
The lamp has worked for a year has the seller (out of stock now) Choice of power and cartridge type: E27/E14/B22 base types and 3 x 3 W / 5 x 3 W / 7 x 3 W in power. I use the minimum power, the track illuminates with a margin.
A friend has been using such a lamp in the hallway for a long time - he is satisfied “like an elephant” - you don’t need to look for a switch, you can see everything right at the entrance to the apartment. You can probably use it on all kinds of stairs, in a parking lot or at the entrance / entrance to the yard, in the garage ... you need to consider that if there is no movement, the lamp shines for about a minute and goes out (wave your hands :)
Comfortable for sure!
The seller stated in the characteristics
Detection range: ? 5 m
Detection angle: about 120 degrees
Power: 5W
Rated voltage: 90-260V
Pros:
Those. Having bought such a lamp (choosing the required type of base, glow color and power) you get a READY product, and there is no need to “finish” something.
Even a woman, even a teenager, can use it “out of the box” - no special connections and improvements are needed.
The quality, as I wrote above, is quite up to par - it worked for a year without turning off without problems.
IMHO it's worth the price! Although the price, perhaps, can be attributed to the minuses :)
Some specific appearance can also be attributed to the minuses (although they are different in the shape and color of the radiator). The more powerful the lamp, the larger the radiator, which may impose some restrictions when using the lamp in fixtures.
Key features of Steinel RS 16L Motion Sensor Luminaire the following:
Dimensions:
275 x 95 mm
Food: 230 - 240 V, 50 Hz
Maximum lamp power:
60 W / E 27
Additional connected power:
up to 100 W
Motion Sensor Viewing Angle:
360° with 160° opening angle through glass, wood and thin walls
Range:
1 - 8 m, continuously adjustable
Light threshold setting interval:
2 - 2000 lx
Glow time setting interval:
5 sec. - 15 minutes.
Ultrasonic sensor operating frequency:
5.8 GHz
IP 44 / II
Radiated power:
1 mW
Steinel RS 16L
The luminaire comes in an elegant box, which contains all the necessary information about its main properties.
The following items are included in the package:
- Luminaire body, with built-in motion sensor
Opal glass shade
Set of fasteners and plugs
A set of additional spacers, warning stickers, etc.
Wiring diagram for a luminaire with a motion sensor
Before installation, electrical wiring was made to install a lamp with a motion sensor - a power cable was brought out that was constantly under voltage.
Such a connection scheme is possible due to the fact that the HF motion sensor installed in the luminaire acts as a switch. This is one of the most important advantages of luminaires with built-in motion sensors, because their operation does not require the implementation of complex circuits, it is enough just to connect the power cable.
In general, all possible connection schemes recommended for a conventional motion sensor can also be implemented for such a lamp, we have already introduced you to the main ones in the article "Motion sensor connection diagram".
Let's start installing a lamp with a motion sensor:
Installation of a lamp with a motion sensor
1. In holes for input cables We install special rubber seals from the delivery set.
2. Turn off the feed electric current at the installation site. To do this, turn off the circuit breaker responsible for this lighting group in the switchboard. If the machines are not signed, turn off everything one by one and check the voltage on the phase wire going to the sconce (usually white or brown), you can determine the presence of voltage using an indicator screwdriver. In no case do not start the installation without turning off the electricity!
3. We stretch the input power cable through the rubber seal into the lamp and shorten it to a length sufficient to connect the wires to the lamp terminals.
4. Fixing the lamp bodywith a motion sensor on the wall, through three mounting holes, as shown in the image below. The choice of fasteners must be made taking into account the type of surface on which the installation is made, in our case, the self-tapping screws from the delivery set were ideal.
5. We prepare the power cable.We remove the braid from it. For the lamp to work, only two wires are enough - phase and zero, grounding is not required here, since the body is made of a dielectric material that does not transmit electric current.
6.
Removing insulation from the ends of the wires, approximately 5 - 7 mm.
7. Connect wires,we place them in the corresponding terminals of the lamp and fix with a screwdriver.
White - PHASE wire - into the terminal marked L.
White with blue stripe- ZERO - to the terminal marked N.
How to determine which of the wires is phase, zero, and which is grounding on your own, our detailed instructions - .
One terminal of the luminaire remains unoccupied (closed with a plug), marked L with a stroke. This is a control terminal, through which you can supply power to other equipment, be it other lamps in the group (may be without a built-in motion sensor), exhaust fans, etc. The only limitation is the power consumption of these devices, it should not exceed 100 watts.
The principle of operation will be as follows - when motion is detected, in the coverage area of the built-in ultrasonic sensor, the lamp will light up and apply voltage to the L terminal with a stroke, after which all devices connected to it will also turn on. This is a very convenient feature, it allows you to significantly expand the scope of lamps with motion sensors in everyday life and at work.
8. In our case, a 13 W LED lamp was chosen, with a warm glow, with the type of e27 base required for the lamp.
9.
We install the ceiling. For this luminaire, the plafond is simply screwed onto the body, while for complete fixation, the plafond is enough to turn only a quarter of a turn.
This completes the installation, we turn on the supply of electric current in the switchboard and test the lamp with an RF motion sensor.
If everything is done correctly, the lamp will immediately light up and if it does not detect movement in the coverage area, it will turn off after a while. You can change the factory settings of a luminaire with a built-in motion sensor as follows:
Adjustment (adjustment) of a lamp with a motion sensor
In our lamp with a built-in motion sensor, there are three parameters available for adjustment, these are:
1. Setting the range (sensitivity) of the motion sensor
2. Time adjustment (on duration)
3. Setting the twilight switch threshold
All settings are made with the help of three regulators hidden under the lamp shade on the body.
Let's see what each of them is responsible for.
1.
Setting the range (sensitivity) of the motion sensor
This adjustment allows you to set the distance at which the motion sensor built into the luminaire can detect movement. The possible adjustment range is from 1 meter (leftmost position) to 8 meters (rightmost position).
2.
Time adjustment (on duration)
This knob sets how long the light will be on. The adjustment range is from 5 seconds (far left) to 15 minutes (far right). When motion is detected, during the period when the lamp is already on, the timer is reset and the time count starts again.
3. Setting the twilight switch threshold.
The required luminaire operation threshold is set in the range from 2 lux (the control is turned to the left) to 2000 lux (the control is turned to the right).
With this adjustment, you can adjust the degree of illumination at which the lamp will turn on. So, if the room is illuminated by natural sunlight during the day, there is no need for the lamp to work and by changing the threshold, you will force the lamp to turn on only at night.
To date, there are a great many different modifications of lamps with motion sensors, of various manufacturers, sizes and shapes, designed for different conditions operation, everyone will find a suitable option for him. The main thing is that they all have a similar principle of operation, and using this article, you can independently install, connect and configure almost any lamp with a built-in motion sensor.
Lighting of the entrances of residential buildings is carried out in accordance with the current regulatory documents. They regulate the intensity of illumination (the number of lumens per meter). At the same time, you can save a lot if you use the most economical LED lamps. And to make the system even more economical, you can install a motion sensor activation system. Of course, this will require investments in the automation unit, but they will quickly pay off due to significant energy savings.
Circuits with automatic switching
A motion sensor is included as a standard solution, but a sound sensor can be used instead. This will provide quite significant benefits:
- Reducing the cost of the system. Instead of a complex infrared motion sensor, a microphone with the simplest electrical thresholding circuit is used.
- The sound sensor does not respond to animals in the entrance.
- The IR motion sensor constantly consumes about 1 - 2 W of power. Sound sensor - 0.1 - 0.5 W.
Features of acoustic sensors
Connecting acoustic sensors is simple, they are inexpensive and have a simple device. When calculating the cost, you need to take into account that you also need an additional light sensor, however, in a standard scheme with an IR motion sensor, instead of a sound one, it is also needed.
When using an acoustic sensor in a security system, it can be noted as an advantage that it is not detected by IR night vision devices. However, one acoustic sensor is often not enough, therefore, when it is necessary to ensure stealth, microwave motion sensors are used instead of common infrared ones.
All sound sensors used in lighting systems are adjustable. To simplify the circuit, the sensor responds only to the amplitude of the sound (its volume). The frequency properties of the sound are ignored. When properly adjusted, the system turns on the light when any noise appears, regardless of its frequency properties. At the same time, it is necessary to select a critical level of operation so that the light turns on only if there are people in the entrance.
Installing LED lamps with a sound sensor in the entrance will provide more high level illumination, since energy is spent only during the presence of people at the entrance.
The critical sound for turning on the light is usually the sound of the door opening, as well as the sound of footsteps. This requires medium microphone sensitivity. It should always be selected individually, depending on the area of the entrance, the location of the microphone and other features of the room.
If the lamp is switched on only by the sound sensor, then it will work during daylight hours. To eliminate this drawback, you need to use a combined circuit: a sound sensor, plus a light sensor. Usually, manufacturers themselves eliminate this drawback and make ready-made designs of automation units for lamps with two sensors. Similar products can be found in the categories of online stores fixtures for housing and communal services. For example, the Light Polus online store offers turnkey solutions for residential building entrances.
Versions of the lighting system with sound sensor
The simplest option - one lamp with a sound sensor is installed on the ceiling. The board with the sound and light sensor is taken out separately or installed in the luminaire housing, if there is free space there. The luminaire input is permanently connected to the network.
It is most rational to assemble the lamp switching circuit on a microcontroller. The circuit board is usually used ready-made. One should contain an acoustic relay, a photo relay, and a timer. The timer is adjustable. Turning off the light after the sound stops depends on the exposure time set. Usually it is selected within 1 - 5 minutes. LEDs, unlike incandescent lamps, do not deteriorate from frequent switching on, so the exposure time can be any.
For lighting large entrances and stairwells, more complex schemes are used:
- One sound sensor at the door with switching of several lamps;
- Separate lamps with built-in sound sensors;
Great opportunities for adjustment will be provided only with a remote automation unit, which must be taken into account during installation. When implementing the scheme, it is recommended to use standard solutions.
Anti-vandal execution
Light sources must have . In guarded entrances, conventional models can be used. Built-in ceiling models are distinguished by the greatest strength. All optical and electronic circuits are protected by thick convex glass.
When using a universal automation unit (sound + light sensor), it can switch all models of fixtures for housing and communal services. Once installed, LED luminaires no longer require maintenance. This is an argument in favor of embedded protected models. They are very convenient for lighting entrances, stairwells, adjoining territories. Mounting - ceiling or wall.
Replacing lamps with LEDs will save not only on electricity consumption, but also on maintenance. The LED life of 50,000 hours allows you to no longer worry about the periodic replacement of burned-out lamps. Residents are no longer bothered by flashing fluorescent or burned out incandescent light bulbs. Lighting becomes modern, reliable and uninterrupted.
Due to low power consumption, theoretical durability and lower prices, incandescent and energy-saving lamps are rapidly replacing. But, despite the declared service life of up to 25 years, they often burn out without even having served the warranty period.
Unlike incandescent lamps, 90% of burned-out LED lamps can be successfully repaired with your own hands, even without special training. The presented examples will help you to repair failed LED lamps.
Before undertaking the repair of an LED lamp, you need to present its device. Regardless of the appearance and type of LEDs used, all LED lamps, including filament bulbs, are arranged in the same way. If you remove the walls of the lamp housing, then inside you can see the driver, which is a printed circuit board with radio elements installed on it.
Any LED lamp is arranged and works as follows. The supply voltage from the contacts of the electric cartridge is supplied to the terminals of the base. Two wires are soldered to it, through which voltage is applied to the input of the driver. From the driver, a DC supply voltage is supplied to the board on which the LEDs are soldered.
The driver is an electronic unit - a current generator that converts the mains voltage into the current required to light the LEDs.
Sometimes, to scatter light or protect a person from touching the unprotected conductors of a board with LEDs, it is covered with a diffusing protective glass.
About filament lamps
By appearance A filament lamp is similar to an incandescent lamp. The device of filament lamps differs from LED ones in that they do not use a board with LEDs as light emitters, but a glass sealed bulb filled with gas, in which one or more filament rods are placed. The driver is located in the base.
The filament rod is a glass or sapphire tube with a diameter of about 2 mm and a length of about 30 mm, on which 28 miniature LEDs are fixed and connected in series coated with a phosphor. One filament consumes about 1 W of power. My operating experience shows that filament lamps are much more reliable than those made on the basis of SMD LEDs. I think over time they will replace all other artificial light sources.
Examples of repair of LED lamps
Attention, the electrical circuits of the LED lamp drivers are galvanically connected to the phase of the electrical network and therefore extreme care must be taken. Touching an unprotected part of the human body to bare parts of a circuit connected to an electrical network can cause serious damage to health, up to cardiac arrest.
LED Lamp Repair
ASD LED-A60, 11 W on SM2082 chip
Currently, powerful LED bulbs have appeared, the drivers of which are assembled on microcircuits of the SM2082 type. One of them worked less than a year and got me to repair. The light bulb flickered randomly and came on again. When tapped on it, it responded with light or extinction. It became obvious that the problem was a bad connection.
To get to the electronic part of the lamp, you need to use a knife to pick up the diffusing glass at the point of contact with the body. Sometimes it is difficult to separate the glass, since silicone is applied to the retaining ring when it is seated.
After removing the light-scattering glass, access to the LEDs and the microcircuit - the current generator SM2082 was opened. In this lamp, one part of the driver was mounted on an aluminum printed circuit board of LEDs, and the second on a separate one.
External inspection did not reveal defective rations or broken tracks. I had to remove the board with LEDs. To do this, the silicone was first cut off and the board was pushed over the edge with a screwdriver blade.
To get to the driver located in the lamp housing, I had to unsolder it, heating two contacts at the same time with a soldering iron and moving it to the right.
One side printed circuit board driver, only an electrolytic capacitor with a capacity of 6.8 microfarads for a voltage of 400 V was installed.
On the reverse side of the driver board, a diode bridge and two series-connected resistors with a nominal value of 510 kOhm were installed.
In order to figure out which of the boards was losing contact, they had to be connected, observing the polarity, using two wires. After tapping the boards with a screwdriver handle, it became obvious that the fault lies in the board with the capacitor or in the contacts of the wires coming from the LED lamp base.
Since soldering did not arouse suspicion, I first checked the reliability of the contact in the central terminal of the base. It is easily removed by prying it over the edge with a knife blade. But the contact was reliable. Just in case, I tinned the wire with solder.
It is difficult to remove the screw part of the base, so I decided to solder the solder wires suitable from the base with a soldering iron. When touching one of the rations, the wire was exposed. Found "cold" soldering. Since there was no way to get to strip the wire, I had to lubricate it with the FIM active flux, and then solder it again.
After assembly, the LED lamp emitted light steadily, despite being hit with a screwdriver handle. Checking the luminous flux for pulsations showed that they are significant at a frequency of 100 Hz. Such a LED lamp can only be installed in luminaires for general lighting.
Driver circuit diagram
LED lamp ASD LED-A60 on the chip SM2082
Electrical circuit of the ASD LED-A60 lamp, thanks to the use in the driver to stabilize the current specialized microcircuit SM2082 turned out to be quite simple.
The driver circuit works as follows. The AC supply voltage is fed through fuse F to the rectifier diode bridge assembled on the MB6S microassembly. The electrolytic capacitor C1 smooths out the ripple, and R1 serves to discharge it when the power is turned off.
From the positive terminal of the capacitor, the supply voltage is applied directly to the LEDs connected in series. From the output of the last LED, the voltage is applied to the input (pin 1) of the SM2082 microcircuit, the current in the microcircuit stabilizes and then from its output (pin 2) it goes to the negative terminal of the capacitor C1.
Resistor R2 sets the amount of current flowing through the LEDs HL. The amount of current is inversely proportional to its nominal value. If the value of the resistor is reduced, then the current will increase, if the value is increased, then the current will decrease. The SM2082 chip allows you to adjust the current value from 5 to 60 mA with a resistor.
LED Lamp Repair
ASD LED-A60, 11W, 220V, E27
Another LED lamp ASD LED-A60, similar in appearance and with the same technical characteristics as the repaired one, got into repair.
When turned on, the lamp lit up for a moment and then did not shine. This behavior of LED lamps is usually associated with a driver malfunction. Therefore, I immediately began to disassemble the lamp.
The diffusing glass was removed with great difficulty, since it was heavily lubricated with silicone along the entire line of contact with the case, despite the presence of a retainer. To separate the glass, I had to look for a pliable place along the entire line of contact with the body with a knife, but still there was a crack in the body.
To gain access to the lamp driver, the next step was to remove the LED printed circuit board, which was pressed into the aluminum insert along the contour. Despite the fact that the board was aluminum, and it was possible to remove it without fear of cracking, all attempts were unsuccessful. The pay was held tight.
It also failed to remove the board together with the aluminum insert, since it fit snugly against the case and was planted on silicone by the outer surface.
I decided to try to remove the driver board from the side of the base. To do this, first, a knife was pulled out of the base, and the central contact was removed. To remove the threaded part of the base, it was necessary to slightly bend its upper shoulder so that the punching points disengaged from the base.
The driver became accessible and freely extended to a certain position, but it was not possible to completely remove it, although the conductors from the LED board were soldered.
There was a hole in the center of the board with the LEDs. I decided to try to remove the driver board by hitting its end through a metal rod threaded through this hole. The board advanced a few centimeters and rested against something. After further blows, the lamp body cracked along the ring and the board with the base of the base separated.
As it turned out, the board had an extension, which rested against the lamp body with its hangers. It looks like the board was shaped in such a way to restrict movement, although it was enough to fix it with a drop of silicone. Then the driver would be removed from either side of the lamp.
The voltage of 220 V from the lamp base through the resistor - fuse FU is fed to the MB6F rectifier bridge and after it is smoothed by an electrolytic capacitor. Next, the voltage is supplied to the SIC9553 chip, which stabilizes the current. Resistors R20 and R80 connected in parallel between terminals 1 and 8 MS set the amount of current to supply the LEDs.
The photo shows a typical electric circuit diagram, given by the manufacturer of the SIC9553 chip in the Chinese datasheet.
This photo shows the appearance of the LED lamp driver from the installation side of the output elements. Since space allowed, to reduce the ripple coefficient of the light flux, the capacitor at the output of the driver was soldered to 6.8 microfarads instead of 4.7 microfarads.
If you have to remove the drivers from the body of this lamp model and you cannot remove the LED board, then you can use a jigsaw to cut the lamp body in a circle just above the screw part of the base.
In the end, all my efforts to extract the driver turned out to be useful only for knowing the device of the LED lamp. The driver was correct.
The flash of the LEDs at the moment of switching on was caused by a breakdown in the crystal of one of them as a result of a voltage surge when the driver was started, which misled me. We had to ring the LEDs first.
An attempt to test the LEDs with a multimeter did not lead to success. The LEDs didn't light up. It turned out that two series-connected light-emitting crystals are installed in one housing, and in order for the LED to start flowing current, it is necessary to apply a voltage of 8 V to it.
A multimeter or tester, switched on to the resistance measurement mode, outputs a voltage in the range of 3-4 V. I had to check the LEDs using the power supply, supplying 12 V to each LED through a 1 kΩ current-limiting resistor.
There was no replacement LED available, so the pads were closed with a drop of solder instead. It is safe for the driver to work, and the power of the LED lamp will decrease by only 0.7 W, which is almost imperceptible.
After the repair of the electrical part of the LED lamp, the cracked body was glued together with Moment's quick-drying super glue, the seams were smoothed by melting the plastic with a soldering iron and smoothed out with sandpaper.
For interest, I performed some measurements and calculations. The current flowing through the LEDs was 58 mA, the voltage was 8 V. Therefore, the power supplied to one LED is 0.46 W. With 16 LEDs, it turns out 7.36 watts, instead of the declared 11 watts. Perhaps the manufacturer indicates the total power consumption of the lamp, taking into account losses in the driver.
The service life of the LED lamp ASD LED-A60, 11 W, 220 V, E27, declared by the manufacturer, is very doubtful to me. In a small volume of a plastic lamp housing with low thermal conductivity, significant power is released - 11 watts. As a result, the LEDs and the driver operate at the maximum allowable temperature, which leads to accelerated degradation of their crystals and, as a result, to a sharp decrease in their MTBF.
LED Lamp Repair
LED smd B35 827 ERA, 7 W on BP2831A chip
A friend shared with me that he bought five light bulbs as in the photo below, and all of them stopped working after a month. He managed to throw away three of them, and, at my request, he brought two for repair.
The light bulb worked, but instead of a bright light, it emitted a flickering weak light at a frequency of several times per second. I immediately assumed that the electrolytic capacitor was swollen, usually if it fails, the lamp begins to emit light, like a stroboscope.
The light-scattering glass was removed easily, it was not glued. It was fixed by a slot on its rim and a protrusion in the lamp body.
The driver was fixed with two solders to a printed circuit board with LEDs, as in one of the lamps described above.
A typical driver circuit on a BP2831A chip taken from the datasheet is shown in the photo. The driver board was removed and all simple radio elements were checked, everything turned out to be in good order. I had to check the LEDs.
The LEDs in the lamp were installed of an unknown type with two crystals in the case and the inspection did not reveal any defects. Using the method of serially connecting the leads of each of the LEDs to each other, he quickly identified the faulty one and replaced it with a drop of solder, as in the photo.
The lamp worked for a week and again got into repair. Shorted the next LED. A week later, I had to short-circuit another LED, and after the fourth I threw out the bulb, because I was tired of repairing it.
The reason for the failure of light bulbs of this design is obvious. LEDs overheat due to insufficient heat sink surface, and their life is reduced to hundreds of hours.
Why is it permissible to close the terminals of burned-out LEDs in LED lamps
The LED lamp driver, unlike the constant voltage power supply, outputs a stabilized current value, not voltage. Therefore, regardless of the load resistance within the given limits, the current will always be constant and, therefore, the voltage drop across each of the LEDs will remain the same.
Therefore, with a decrease in the number of series-connected LEDs in the circuit, the voltage at the output of the driver will also decrease proportionally.
For example, if 50 LEDs are connected in series to the driver, and a voltage of 3 V drops across each of them, then the voltage at the output of the driver was 150 V, and if 5 of them were shorted, the voltage would drop to 135 V, and the current would not change.
But the coefficient of performance (COP) of a driver assembled according to such a scheme will be low and power losses will be more than 50%. For example, for an MR-16-2835-F27 LED bulb, you will need a 6.1 kΩ resistor with a power of 4 watts. It turns out that the driver on the resistor will consume power that exceeds the power consumption of the LEDs and place it in a small package LED lamps, due to the release of more heat, will be unacceptable.
But if there is no other way to repair the LED lamp and it is very necessary, then the driver on the resistor can be placed in a separate case, all the same, the power consumption of such an LED lamp will be four times less than incandescent lamps. At the same time, it should be noted that the more LEDs connected in series in the light bulb, the higher the efficiency will be. With 80 serially connected SMD3528 LEDs, you will need an 800 ohm resistor with a power of only 0.5 watts. Capacitor C1 will need to be increased to 4.7 µF.
Finding faulty LEDs
After removing the protective glass, it becomes possible to check the LEDs without peeling off the printed circuit board. First of all, a careful inspection of each LED is carried out. If even the smallest black dot is detected, not to mention the blackening of the entire surface of the LED, then it is definitely faulty.
When examining the appearance of the LEDs, you need to carefully examine the quality of the rations of their conclusions. In one of the light bulbs being repaired, four LEDs were poorly soldered at once.
The photo shows a light bulb that had very small black dots on four LEDs. I immediately noted faulty LEDs crosses so that they can be clearly seen.
Faulty LEDs may or may not change appearance. Therefore, it is necessary to check each LED with a multimeter or arrow tester included in the resistance measurement mode.
There are LED lamps in which standard LEDs are installed in appearance, in the case of which two crystals connected in series are mounted at once. For example, lamps of the ASD LED-A60 series. To make such LEDs ring, it is necessary to apply a voltage of more than 6 V to its outputs, and any multimeter gives out no more than 4 V. Therefore, such LEDs can only be checked by applying a voltage of more than 6 (9-12) V through a 1 kΩ resistor from the power source. .
The LED is checked, like a conventional diode, in one direction the resistance should be equal to tens of megaohms, and if you swap the probes (this changes the polarity of the voltage supply to the LED), then it is small, while the LED may glow dimly.
When checking and replacing LEDs, the lamp must be fixed. To do this, you can use a suitable size round jar.
You can check the health of the LED without an additional DC source. But such a verification method is possible if the light bulb driver is working. To do this, it is necessary to apply a supply voltage to the LED bulb base and short the leads of each LED in series with each other with a wire jumper or, for example, metal tweezers sponges.
If suddenly all the LEDs light up, then the shorted one is definitely faulty. This method is useful if only one LED out of all in the circuit is faulty. With this method of verification, it must be taken into account that if the driver does not provide galvanic isolation from the mains, as, for example, in the diagrams above, then touching the LED solderings with your hand is unsafe.
If one or even several LEDs turned out to be faulty and there is nothing to replace them with, then you can simply short-circuit the contact pads to which the LEDs were soldered. The light bulb will work with the same success, only the luminous flux will decrease slightly.
Other malfunctions of LED lamps
If the test of the LEDs showed their serviceability, then the reason for the inoperability of the light bulb lies in the driver or in the places where the current-carrying conductors are soldered.
For example, in this light bulb, a cold soldered conductor was found that supplies voltage to the printed circuit board. The soot released due to poor soldering even settled on the conductive tracks of the printed circuit board. The soot was easily removed by wiping with a rag soaked in alcohol. The wire was soldered, stripped, tinned and re-soldered into the board. Good luck with this lamp.
Of the ten failed light bulbs, only one had a faulty driver, the diode bridge fell apart. The repair of the driver consisted in replacing the diode bridge with four IN4007 diodes, designed for a reverse voltage of 1000 V and a current of 1 A.
Soldering SMD LEDs
To replace a faulty LED, it must be desoldered without damaging the printed conductors. From the donor board, you also need to solder the replacement LED without damage.
It is almost impossible to solder SMD LEDs with a simple soldering iron without damaging their case. But if you use a special tip for a soldering iron or put on a standard tip a nozzle made of copper wire, then the problem is easily solved.
The LEDs have polarity and when replacing, you need to correctly install it on the printed circuit board. Typically, printed conductors follow the shape of the leads on the LED. Therefore, you can make a mistake only if you are inattentive. To solder the LED, it is enough to install it on a printed circuit board and heat its ends with contact pads with a soldering iron with a power of 10-15 W.
If the LED burned out to charcoal, and the printed circuit board under it was charred, then before installing a new LED, it is imperative to clean this place of the printed circuit board from burning, since it is a current conductor. When cleaning, you may find that the pads for soldering the LED are burned or peeled off.
In such a case, the LED can be installed by soldering it to adjacent LEDs if the printed tracks lead to them. To do this, you can take a piece of thin wire, bend it in half or three, depending on the distance between the LEDs, tin and solder to them.
Repair LED lamp series "LL-CORN" (corn lamp)
E27 4.6W 36x5050SMD
The device of the lamp, which is popularly called the corn lamp, shown in the photo below, differs from the lamp described above, therefore the repair technology is different.
The design of LED SMD lamps of this type is very convenient for repair, as there is access for LED continuity and replacement without disassembling the lamp housing. True, I still dismantled the light bulb for interest in order to study its device.
Examination LEDs corn lamps do not differ from the technology described above, but it must be taken into account that three LEDs are placed in the SMD5050 LED housing, usually connected in parallel (three dark dots of crystals are visible on the yellow circle), and when checking, all three should glow.
A defective LED can be replaced with a new one or shorted with a jumper. This will not affect the reliability of the lamp, only imperceptibly to the eye, the luminous flux will decrease slightly.
The driver of this lamp is assembled according to the simplest circuit, without an isolation transformer, so touching the LED leads when the lamp is on is unacceptable. Lamps of this design are unacceptable to be installed in fixtures that can be reached by children.
If all the LEDs are working, then the driver is faulty, and in order to get to it, the lamp will have to be disassembled.
To do this, remove the bezel from the side opposite the base. With a small screwdriver or a knife blade, you need to try in a circle to find weakness where the bezel is the worst glued. If the rim succumbed, then working with the tool as a lever, the rim will easily move away around the entire perimeter.
The driver was built wiring diagram, like the MR-16 lamp, only C1 had a capacity of 1 µF, and C2 - 4.7 µF. Due to the fact that the wires from the driver to the lamp base were long, the driver was easily pulled out of the lamp housing. After studying his circuit, the driver was inserted back into the case, and the bezel was glued into place with transparent Moment glue. The failed LED was replaced with a good one.
Repair of LED lamp "LL-CORN" (corn lamp)
E27 12W 80x5050SMD
When repairing a more powerful lamp, 12 W, there were no failed LEDs of the same design, and in order to get to the drivers, I had to open the lamp using the technology described above.
This lamp gave me a surprise. The wires from the driver to the base were short, and it was impossible to remove the driver from the lamp housing for repair. I had to remove the plinth.
The base of the lamp was made of aluminium, rounded and held tight. I had to drill out the attachment points with a 1.5 mm drill. After that, the plinth, which was hooked with a knife, was easily removed.
But you can do without drilling the base, if you pry the edge of the knife around the circumference and slightly bend its upper edge. A mark should first be placed on the plinth and body so that the plinth can be easily installed in place. To securely fix the base after repairing the lamp, it will be enough to put it on the lamp body so that the punched points on the base fall into their old places. Next, push these points with a sharp object.
Two wires were connected to the thread with a clamp, and the other two were pressed into the central contact of the base. I had to cut these wires.
As expected, there were two identical drivers, feeding 43 diodes each. They were covered with heat shrink tubing and taped together. In order for the driver to be placed back into the tube, I usually carefully cut it along the printed circuit board from the side where the parts are installed.
After repair, the driver is wrapped in a tube, which is fixed with a plastic tie or wrapped with several turns of thread.
In the electrical circuit of the driver of this lamp, protection elements are already installed, C1 for protection against impulse surges and R2, R3 for protection against current surges. When checking the elements, resistors R2 were immediately found on both drivers in the open. It appears that the LED lamp was supplied with a voltage exceeding the allowable voltage. After replacing the resistors, there was no 10 Ohm at hand, and I set it to 5.1 Ohm, the lamp worked.
Repair LED lamp series "LLB" LR-EW5N-5
The appearance of this type of light bulb inspires confidence. Aluminum case, high-quality workmanship, beautiful design.
The design of the light bulb is such that it is impossible to disassemble it without the use of significant physical effort. Since the repair of any LED lamp begins with checking the health of the LEDs, the first thing that had to be done was to remove the plastic protective glass.
The glass was fixed without glue on a groove made in the radiator with a shoulder inside it. To remove the glass, you need to use the end of a screwdriver, which will pass between the radiator fins, to lean on the end of the radiator and, as a lever, lift the glass up.
Checking the LEDs with a tester showed their serviceability, therefore, the driver is faulty, and you need to get to it. The aluminum board was fastened with four screws, which I unscrewed.
But contrary to expectations, behind the board was the plane of the radiator, lubricated with heat-conducting paste. The board had to be returned to its place and continue to disassemble the lamp from the side of the base.
Due to the fact that the plastic part to which the radiator was attached was very tight, I decided to go the proven way, remove the base and remove the driver for repair through the opened hole. I drilled out the punching points, but the base was not removed. It turned out that he was still holding on to the plastic due to the threaded connection.
I had to separate the plastic adapter from the radiator. He held, as well as protective glass. To do this, washed down with a hacksaw at the junction of the plastic with the radiator and by turning a screwdriver with a wide blade, the parts were separated from each other.
After soldering the leads from the printed circuit board of the LEDs, the driver became available for repair. The driver circuit turned out to be more complex than previous light bulbs, with an isolation transformer and a microcircuit. One of the 400 V 4.7 µF electrolytic capacitors was swollen. I had to replace it.
A check of all semiconductor elements revealed a faulty Schottky diode D4 (pictured below left). There was a SS110 Schottky diode on the board, I replaced it with the existing analog 10 BQ100 (100 V, 1 A). The forward resistance of Schottky diodes is two times less than that of ordinary diodes. The LED lamp lit up. The same problem was with the second bulb.
Repair LED lamp series "LLB" LR-EW5N-3
This LED lamp is very similar in appearance to the "LLB" LR-EW5N-5, but its design is somewhat different.
If you look closely, you can see that at the junction between the aluminum radiator and the spherical glass, unlike LR-EW5N-5, there is a ring in which the glass is fixed. To remove the protective glass, just use a small screwdriver to pick it up at the junction with the ring.
Three nine crystal superbright LEDs are installed on the aluminum circuit board. The board is screwed to the heatsink with three screws. Checking the LEDs showed their serviceability. Therefore, you need to repair the driver. Having experience in repairing a similar LED lamp "LLB" LR-EW5N-5, I did not unscrew the screws, but soldered the current-carrying wires coming from the driver and continued to disassemble the lamp from the side of the base.
The plastic connecting ring of the plinth with the radiator was removed with great difficulty. At the same time, part of it broke off. As it turned out, it was screwed to the radiator with three self-tapping screws. The driver is easily removed from the lamp housing.
The self-tapping screws that screw the plastic ring of the base cover the driver, and it is difficult to see them, but they are on the same axis with the thread to which the adapter part of the radiator is screwed. Therefore, a thin Phillips screwdriver can be reached.
The driver turned out to be assembled according to the transformer circuit. Checking all the elements, except for the microcircuit, did not reveal any failed ones. Therefore, the microcircuit is faulty, I did not even find a mention of its type on the Internet. The LED bulb could not be repaired, it will come in handy for spare parts. But studied her device.
Repair LED lamp series "LL" GU10-3W
It turned out, at first glance, that it was impossible to disassemble a burned-out GU10-3W LED bulb with a protective glass. An attempt to remove the glass led to its puncture. With the application of great effort, the glass cracked.
By the way, in the marking of the lamp, the letter G means that the lamp has a pin base, the letter U means that the lamp belongs to the class of energy-saving light bulbs, and the number 10 means the distance between the pins in millimeters.
LED bulbs with a GU10 base have special pins and are installed in a socket with a turn. Thanks to the expanding pins, the LED lamp is clamped in the socket and is held securely even when shaking.
In order to disassemble this LED light bulb, I had to drill a hole with a diameter of 2.5 mm in its aluminum case at the level of the surface of the printed circuit board. The drilling location must be chosen in such a way that the drill does not damage the LED when exiting. If there is no drill at hand, then the hole can be made with a thick awl.
Next, a small screwdriver is threaded into the hole and, acting like a lever, the glass is lifted. I removed the glass from two light bulbs without problems. If the test of the LEDs by the tester showed their serviceability, then the printed circuit board is removed.
After separating the board from the lamp housing, it immediately became obvious that the current-limiting resistors burned out in both one and the other lamp. The calculator determined their denomination from the bands, 160 ohms. Since the resistors burned out in LED bulbs of different batches, it is obvious that their power, judging by the size of 0.25 W, does not correspond to the power released when the driver is operating at maximum ambient temperature.
The printed circuit board of the driver was solidly filled with silicone, and I did not disconnect it from the board with LEDs. I cut off the leads of the burnt resistors at the base and soldered more powerful resistors to them, which were at hand. In one lamp, a 150 Ohm resistor with a power of 1 W was soldered, in the second two in parallel 320 Ohm with a power of 0.5 W.
In order to prevent accidental contact with the output of the resistor, to which the mains voltage is suitable with the metal body of the lamp, it was insulated with a drop of hot melt adhesive. It is waterproof and an excellent insulator. I often use it for sealing, insulating and securing electrical wires and other parts.
Hotmelt adhesive is available in the form of rods with a diameter of 7, 12, 15 and 24 mm in different colors, from transparent to black. It melts, depending on the brand, at a temperature of 80-150 °, which allows it to be melted with an electric soldering iron. It is enough to cut off a piece of the rod, place it in the right place and heat it up. The hot melt will take on the consistency of May honey. After cooling it becomes solid again. When reheated, it becomes liquid again.
After replacing the resistors, the performance of both bulbs was restored. It remains only to fix the printed circuit board and the protective glass in the lamp housing.
When repairing LED lamps, I used liquid nails "Installation" moment to fix printed circuit boards and plastic parts. The glue is odorless, adheres well to the surfaces of any materials, remains plastic after drying, has sufficient heat resistance.
It is enough to take a small amount of glue on the end of a screwdriver and apply it to the places where the parts come into contact. After 15 minutes, the glue will already hold.
When gluing the printed circuit board, in order not to wait, holding the board in place, as the wires pushed it out, fixed the board additionally at several points with hot glue.
The LED lamp began to flash like a strobe
I had to repair a pair of LED lamps with drivers assembled on a microcircuit, the malfunction of which consisted in flashing light at a frequency of about one hertz, like in a strobe.
One instance of the LED lamp began to flash immediately after being turned on for the first few seconds and then the lamp began to glow normally. Over time, the duration of the lamp flashing after switching on began to increase, and the lamp began to flash continuously. The second copy of the LED lamp began to flash continuously all of a sudden.
After disassembling the lamps, it turned out that the electrolytic capacitors installed immediately after the rectifier bridges failed in the drivers. It was easy to determine the malfunction, since the capacitor cases were swollen. But even if the capacitor looks without external defects in appearance, it is still necessary to start repairing the LED light bulb with a stroboscopic effect by replacing it.
After replacing the electrolytic capacitors with serviceable ones, the stroboscopic effect disappeared and the lamps began to shine normally.
Online calculators for determining the value of resistors
by color coding
When repairing LED lamps, it becomes necessary to determine the value of the resistor. According to the standard, the marking of modern resistors is carried out by applying colored rings to their cases. 4 colored rings are applied to simple resistors, and 5 to high-precision resistors.
