LED floodlights are a very popular thing today. But, like any electronics, spotlights break down relatively often. Repair LED spotlights with your own hands is what today’s article will focus on.
All the theory on the design of LED spotlights and terminology, and here is practice for home craftsmen.
The spotlight doesn't light up - where to start?
First of all, you need to make sure that 220 V power is supplied to the driver. This is Azy.
Checking the driver
Let me remind you that the word “driver” is a marketing ploy to designate a current source designed for a specific matrix with a certain current and power.
In order to test the driver without an LED (idle, without load), simply apply 220V to its input. A constant voltage should appear at the output, a value slightly greater than the upper limit indicated on the block.
For example, if the range of 28-38 V is indicated on the driver unit, then when it is turned on idle, the output voltage will be approximately 40V. This is explained by the principle of operation of the circuit - to maintain the current in a given range of ±5%, when the load resistance increases (idle = infinity), the voltage must also increase. Naturally, not to infinity, but to some upper limit.
However, this test method does not allow us to judge whether the LED driver is 100% serviceable.
The fact is that there are serviceable units that, when turned on idle, without load, either will not start at all, or will produce something unclear.
I suggest connecting a load resistor to the output of the LED driver to provide it with the desired operating mode. How to choose a resistor - according to Uncle Ohm's law, looking at what is written on the driver.
LED driver 20 W. Stable output current 600 mA, voltage 23-35 V.
For example, if it says Output 23-35 VDC 600 mA, then the resistor resistance will be from 23/0.6=38 Ohms to 35/0.6=58 Ohms. We choose from a range of resistances: 39, 43, 47, 51, 56 Ohms. The power must be appropriate. But if you take 5 W, then it will be enough for a few seconds to check.
Attention! The driver output, as a rule, is galvanically isolated from the 220V network. However, you should be careful - cheap circuits may not have a transformer!
If, when connecting the required resistor, the output voltage is within the specified limits, we conclude that the LED driver is working.
Checking the LED matrix
To check you can use laboratory block nutrition, . We supply a voltage that is obviously lower than the nominal voltage. We control the current. The LED matrix should light up.
What to do if the power of the LED module is unknown
There are situations when there is an LED chip, but its power, current and voltage are unknown. Accordingly, it is difficult to buy it, and if it is working, it is not clear how to choose an adapter.
This was a big problem for me until I figured it out. I’m sharing with you how to determine the voltage, power and current of an LED assembly by looking at its appearance.
For example, we have a spotlight with the following LED assembly:
9 diodes. 10 W, 300 mA. In fact - 9 W, but this is within the margin of error.
The problem is that the LED matrices of the floodlights use 1 W diodes. The current of such diodes is 300...330 mA. Naturally, all this is approximately, within the margin of error, but in practice it works accurately.
In this matrix, 9 diodes are connected in series, they have one current (300 mA), and a voltage of 3 Volts. As a result, the total voltage is 3x9 = 27 Volts. For such matrices, you need a driver with a current of 300 mA, a voltage of approximately 27V (usually from 20 to 36V). The power of one such diode, as I said, is about 9 W, but for marketing purposes this spotlight will have a power of 10 W.
The 10 W example is a bit atypical due to the special arrangement of the LEDs.
Another example, more typical:
You already guessed it two horizontal rows of dots of 10 pieces each are LEDs. One strip is, offhand, 30 Volts, current 300 mA. Two strips connected in parallel - voltage 30 V, current twice as much, 600 mA.
A couple more examples:
Total - 50 W, current 300x5 = 1500 mA.
Total - 70 W, 300x7 = 2100 mA.
I think there is no point in continuing, everything is already clear.
The situation is slightly different with LED modules based on discrete diodes. According to my calculations, one diode there usually has a power of 0.5 W. Here is an example of a GT50390 matrix installed in a 50 W floodlight:
LED floodlight Navigator, 50 W. LED module GT50390 - 90 discrete diodes
If, according to my assumptions, the power of such diodes is 0.5 W, then the power of the entire module should be 45 W. Its circuit will be the same, 9 lines of 10 diodes each with a total voltage of about 30 V. The operating current of one diode is 150...170 mA, the total current of the module is 1350...1500.
Anyone who has other thoughts on this matter is welcome to comment!
LED spotlight driver repair
It is better to start repairs by searching for the electrical circuit of the LED driver.
As a rule, LED spotlight drivers are built on a specialized MT7930 chip. In the article about the Design of Spotlights, I gave a photo of a board (not waterproof) based on this chip, once again:
LED floodlight Navigator, 50 W. Driver. GT503F board
Attention! Information on driver circuits and a little more on repairs!
LED replacement
There are no special tricks when replacing the LED matrix, but you need to pay attention to the following things.
- Carefully remove old heat-conducting paste,
- Apply thermal conductive paste to the new LED. It is best to do this with a plastic card,
- fix the diode evenly, without distortions,
- remove excess paste,
- do not confuse the polarity,
- Do not overheat when soldering.
When repairing an LED module consisting of discrete diodes, first of all you need to pay attention to the integrity of the soldering. And then check each diode by applying a voltage of 2.3 - 2.8 V to it.
Where to get spare parts for repairs
If you need quick repairs, then the best thing, of course, is to run to the store across the street.
But if you are engaged in repairs on an ongoing basis, then it is better to look where it is cheaper. I recommend doing this on the well-known AliExpress website.
I provide several links for reference and examples, there is a lot of interesting information there, including descriptions, photos and selection.
LED matrices:
- Led Chip large selection from 10 to 100 W, from 48 to 360 rubles.
- Powerful LEDs.
Drivers for LED spotlights, for different powers:
- 30W waterproof DC power supply,
- 50W waterproof DC power supply,
- Waterproof Outdoor LED Drivers 10, 20, 30, 50W DC.
And who doesn’t want to repair, you can immediately order something ready-made:
LED street floodlights:
- Outdoor floodlights from 10 to 50 W,
- Waterproof flat floodlights from 10 to 100 W, LED Chip+Driver kit available.
To complete the picture, here is a video from my colleagues, they share their experience:
I'll end here. I encourage my colleagues to share their experiences and ask questions!
My previous job generously supplied me with corpses of LED lamps and fixtures. Without going into technical details, more than 99% of what is sold everywhere is outright slag, fundamentally incapable of working for any long time due to clearly insufficient, or even absent, cooling.
Here is an example of complete slag: a bullshit pure plastic “radiator”. the result is predictable: the LEDs are burnt out, blackening of the crystals is visible, and they self-soldered out
another dead guy
The “old-style” LED spotlights with a solid-cast aluminum radiator body were relatively well made, but they are rapidly disappearing from sale.
old style spotlight
old style spotlight
But, apparently, the sellers and Ketai people decided that so much lumini was too fat, and they optimized these spotlights. Now “new sample” floodlights with a plastic housing and a separate radiator are on sale everywhere.
New 30W floodlight
The cartridge was supplied for sizing purposes. The radiator has a fin area of approximately 200 sq.cm. The result is predictable: the heatsink heats up around +100 degrees, rapid degradation and failure of the LEDs
Guts floodlight 30W
Please note: there are 60pcs of 0.5W LEDs type 5630. diodes are used 100%. Reserve by mode? what nonsense, have not heard. And my electronics teacher back in the 80s used to say that those who use components at >60% of the limiting modes are either idiots or greedy bourgeois.
Here the circuit design of the emitter is as follows: 2 parallel groups of 30 serial 5630. The forward voltage is around 90V at +25g r, and the current is 300mA.
The LEDs are mounted on a luminous board, which is screwed only at the corners. The fit is loose.
the result is in the photo. In a measly 100 operating hours, the phosphor had already become very black, several diodes had burned out, burning black holes in the phosphor. The driver also died. I re-connected the groups of LEDs in series, the driver was down-graded to a stupid capacitor one.
emitter large
It was experimentally found that such a radiator is capable of maintaining a reasonable temperature on the crystals in the region of +80°C and +60°C on the radiator, with only 1/3 of the nominal power of the spotlight. That’s what I did, the current was reduced threefold.
The picture is approximately the same for other powers of spotlights of this type: terrible overheating and rapid dying
morality? Avoid purchasing such “new style” floodlights; if possible, look for solid cast “old style” floodlights.
By the way, pay attention to the drivers of different spotlights. They do not have a class capacitor in the rectifier. This is how manufacturers fight for a decent cosine phi. Needless to say, the 100Hz output ripple is enormous. Output capacitors do not help. Do not use such spotlights where you work for a long time, protect your eyes. At a minimum, it is useful to add electrolyte to the rectifier, at least 10 µF for every 10 W
also note that all drivers, and even those LED lamps too, made according to the “step-down” scheme, i.e. there is not a transformer, but a choke, and there is no isolation from the network! Be extremely careful! The chip-to-substrate insulation is clearly not designed for mains voltage.
LED floodlight drivers
Power
The power of the driver must match the power of the spotlight, or more precisely, the matrix in the spotlight. Do not rely on the power indicated on the body of the spotlight! We have had spotlights brought to us for repair many times, proudly labeled 50W in half a body with a 30-watt driver and matrix inside. Installing a 50-watt driver in such a product will not end well. It is imperative to read the labeling of the burnt driver.
Dimensions
The driver must physically fit inside the LED floodlight. And you still need to lay the wires.
We have the exact driver sizes listed on our website.
Driver output current value
The output current value is always indicated on the driver housing. This is the current that the driver will supply to the matrix. This value varies from approximately 300mA to 3000mA and must match the matrix supply current. Deviations of more than 5% are unacceptable.
Output voltage range
The driver output voltage range is the two voltage values within which the driver attempts to stabilize the current.
Numbers can range from 20 to 150 volts.
This range must coincide with the corresponding characteristic of the matrix, or, if it is unknown, the range of output voltages of the burnt driver.
This parameter does not have to match as exactly as the current value, but there should be an approximate match.
Input voltage - 220 volts
We produce different drivers for LED spotlights, not only for 220 volts. Therefore, when purchasing a driver, make sure that you have a driver for the input voltage you need - all drivers presented in this section are designed for 220, 127 and 110 volt networks.
For those who haven’t read it, let me remind you briefly. Recently, a powerful 120 W LED floodlight was brought in for repairs; it only worked for a year. As it turned out, his driver burned out. And there I started whining about the fragility of switching power supplies and wondered about finding a simpler and more reliable solution. Today I decided to assemble and test the operation of a circuit with a quenching capacitor. A similar circuit is widely used to power LED spotlights.
Preliminarily calculated the capacity of the quenching capacitor using the well-known formula
For the calculation I took the following parameters:
Uc (mains voltage) = 220 V;
U (voltage at the input of the diode bridge) = 60 V;
I (nominal LED current) = 1.8 A;
According to calculations, it turned out that a capacitor with a capacity of 27 μF is needed. I went through the bins, collected all sorts of different capacitors to provide the required capacity, and also experimented with the deviation of the capacity from the calculated value. To avoid misunderstandings, the capacitance of all capacitors was measured with an E7-16 immittance meter.
Despite the venerable age of some specimens, the capacity practically corresponded to the specified one.
I soldered the circuit. In order not to bother too much, I used the power part from the computer power supply board. The result is this design
It was interesting to find out to what extent the current will change when the input voltage deviates by 20% from the nominal value with different values of the quenching capacitor capacitance. The experiments were carried out with LEDs preheated for 30 minutes. The measurement results were tabulated and presented in graphical form. During the measurement process, the voltage on capacitor C2 varied within 58 V...62, I decided not to include these values in the table due to their insignificant change.
The graphs turned out to be linear
The native driver ensured that the current flowing through the LEDs was maintained at a level of 1.8 A. According to various sources, the rated current of a 60 W LED ranges from 1.8 to 2 A, different sellers indicate different currents. We will assume that a current above 1.8 A is undesirable.
If you choose a capacitor with a capacity of 24 μF, then when the input voltage increases to 260 V, the current through the LEDs will not exceed the rated value. In normal mode, with an input voltage of 220 V, a current of 1.5 A is provided, which corresponds to a power consumption of 90 W. At a rated current of 1.8 A, the calculated power is about 110 W. Thus, with an input voltage of 220 V, we have a power reduction of 20 W (18%) relative to the nominal value. On the one hand, a lower current value increases the service life of the LED, but leads to a decrease in the brightness of the glow, although this is not particularly noticeable to the eye. It would be nice to measure the brightness with an appropriate device, but it is not available.
Although LED technology is very reliable, it cannot be perfect and sometimes fails. Especially if you decide to save a lot and purchase one of the cheapest floodlights. So what to do if your LED floodlight, or even worse, stopped working altogether, and your warranty on the purchased product has expired, or did not start at all. It is quite possible that you purchased a non-certified product from a reliable store with a good reputation, and at your own peril and risk ordered the most affordable LED spotlight directly from China, through Aliexpress, for example? And now a far from cheap lighting device lies in front of you and blinks or does not shine at all, and you don’t know what to do? Don't give up. In this article we will tell you how to repair the device yourself.
In order to repair an LED processor with your own hands, you must confidently hold a multimeter (in the picture below) and a soldering iron in your hands. This is necessary in order to be able to determine the cause of the breakdown, and, in fact, ultimately eliminate it, bringing the device back to life.
Probable causes of failure and ways to eliminate them
Current limiting capacitor
So, first of all, you need to determine the cause of the malfunction of your device. If the spotlight turns on, but when turned on does not burn evenly, but flickers and blinks, the current-limiting capacitor C1 has probably failed. Many Chinese manufacturers make the mistake of using a current-limiting capacitor that does not match the parameters of the driver when trying to achieve maximum brightness from a not very powerful spotlight. A current-limiting capacitor at 400 volts rated operating voltage will do just fine.
power unit
Another common cause may be a failed power supply. There are two options for getting out of the situation - contact an electronics store, where they will help you choose a suitable power supply (its characteristics are indicated on it, therefore it is advisable to disassemble the spotlight and take the unit with you), or select a power supply (may be suitable from a scanner or printer).
The second option is possible, of course, only if you suddenly have unnecessary and non-working office equipment lying around that can serve as a power supply donor. Check the power supplies so that they are similar in parameters. An exact match is not necessary, but the parameters should not diverge too much. As mentioned earlier, if you have the skills to use tools and understand electronics, you can easily change the power supply yourself.
Driver
If a low-power spotlight needs repair, it is likely that it may not have its own power supply, and the function of changing currents in it is performed by the LED driver. Since the LED cannot be powered directly from the network, requiring alternating current that differs from what the network can offer it, the floodlight uses a driver that takes into account the variation in LED characteristics depending on operating temperature and time, adjusting the output current supplied to the LED. It is this driver that can fail.
To replace it, you will need to disassemble the LED spotlight and find out the driver markings in order to buy or order a replacement. If you are a confident user of power tools, you can find a failed driver element and unsolder it and replace it. If you are repairing, most likely it will be quite easy for you to find the problem in the driver or find a similar driver and make a replacement. It will definitely be cheaper than buying or assembling a new spotlight from scratch.
Matrix burnout
Another option for failure of the design of your LED spotlight, in addition to a malfunction of the driver, power supply or other small elements involved in the current conversion process, may be the burnout of the LED matrix itself. If the LED itself fails, you need to find and purchase a diode with similar characteristics. After disassembling the spotlight, you will need to carefully uninstall the burnt matrix by unscrewing the four fastening screws and unsoldering the conductive elements. Then you will need to evenly and carefully apply a layer of thermal paste to the new diode, solder the current-carrying elements and carefully screw the matrix. It is necessary to take into account that the shape of the matrix must remain intact, that is, it is advisable to use the same screws that were originally used. They should not have conical heads, because if you use them, if you tighten them with a little more force, they can damage the matrix and all your work will be in vain.
Let's sum it up
To repair an LED spotlight yourself, you must at least have good skills in working with a soldering iron, testers and a multimeter, as well as understand circuit diagrams or be able to read them in order to find the cause of the malfunction, unsolder the faulty element and replace it.
If the driver or power supply in your spotlight fails, you can find a replacement and bring the lighting device back to life. Just like with the driver, a replacement can be made with an LED matrix - just buy an analogue with similar characteristics. If for some reason the device does not work after your manipulations, it probably makes sense to purchase a new one. But if you are confident in your abilities, you can always assemble an LED spotlight with your own hands - it will be easier to repair it in the future, or replace some elements, constantly extending the life of the device.
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.
Let us remind you that the service life of LEDs is the longest among lighting sources. Premature failure of LED floodlights is associated with several factors, some of which are quite predictable.
The first and most common
The purchased spotlight had a minimum price. In this case, its inoperability is directly related to the quality of the components used. In such spotlights, the cheapest and non-compliant power supplies are installed; it is not uncommon for the power supply to not even have a degree of protection and not be located in a closed housing (meaning the power supply housing).
The contacts in the spotlight's power circuit from the mains to the power supply and from the power supply to the LED have a poor connection, which also leads to a short circuit and failure.
The degree of protection does not correspond to the declared one. In cheap options, instead of a silicone seal, a cheap rubber analogue is installed, which simply collapses due to time and differences in ambient temperature.
The second case, which also occurs
The LED spotlight has a manufacturing defect. Yes, this also happens and no one is immune from it. Most often the reason is in the power supply. If during the first month of operation the lamp fails, then it is most likely that it is the power supply. In practice, if a spotlight has worked for more than 1 month, then it must work out the entire declared service life.
But in any case, you can rest assured that if the spotlight fails due to a manufacturing defect, then most likely it can be replaced under warranty, which is still nice.
The third case also happens
Most often it is found in enterprises. This is a failure due to strong and long voltage drops. Although the LED spotlight is designed to withstand voltage surges, but only for short-term ones. In the case of factories and enterprises, sometimes the voltage drops catastrophically at times and at the same moment rises. At such moments, the power supply simply cannot cope and because of this the LED simply burns out.
Here the warranty will not help, since this is not a manufacturing defect, but a violation of the operation of the lamp.
Should I repair the LED floodlight?
Today, it is worth admitting that this idea makes absolutely no sense. The cost of components in retail sales often reaches the price of a more or less high-quality LED spotlight. And the most unpleasant thing is that no one will give you a guarantee that if you buy, for example, a power supply instead of a non-working one, it will match the LED with which the faulty power supply worked.
Therefore, if the LED spotlight does not work and there is no warranty for it for any reason, you should safely go and buy a new, high-quality LED spotlight. We wrote about how to choose the right LED spotlight.
Constant problems with lighting that arise at home require troubleshooting yourself. And it is not difficult to agree that systematically calling a specialist to repair an LED device is a rather expensive service today. Therefore, in order to avoid some discomfort, it is recommended to repair the LED spotlight yourself.
A modern LED spotlight is considered a popular and quite popular device that is used for lighting local area. Such a lighting device is very convenient to use, but, of course, there comes a time when it breaks down and requires timely repair. Therefore, it is definitely necessary to have the skills to correctly identify faults, eliminate dysfunction, and also restore the equipment to its previous condition. It should be noted that basic LED floodlights do not provide for replacing the light sources with another one with excellent power.
The main causes of spotlight malfunction
Often the cause of a breakdown is overheating of the matrix, as a result of which all fuses burn out. Indirect reasons that lead to spotlight dysfunction are considered to be:
- short circuit;
- overvoltage;
- incorrect network connection;
- connection of overcurrents;
- non-compliance with the device connection diagram.
Before you start repairing an LED spotlight with your own hands, it is recommended to thoroughly examine the formation of a matrix defect. Typically, a matrix is a device that operates using crystals. Basically there are dozens of them, but if 5-7 crystals malfunction, the device continues to function as before. Only complete combustion of the matrix requires intervention. But according to experts, in such situations it is advisable to completely replace the matrix. It should be noted that during repair work it is strongly recommended to insulate the conductors of the spotlight.
Often a malfunction LED sources occurs due to malfunctions of the drivers that power the crystal surface of the spotlight. If the device becomes unusable even before the expiration of the warranty period, then the place where the device was purchased should provide assistance or make a replacement. Otherwise, you will have to think about how to make an LED spotlight yourself, or pay for repairs to specialists.
Features of DIY LED spotlight repair
Before starting repairs, it is recommended to prepare the necessary set of tools and clarify the cause of the device malfunction. Any breakdown must be repaired properly to avoid another problem occurring.
The main candidates for repair are LED floodlights made in China, which have an average power of 10 watts. It is with this example that we can consider solving a problem associated with a breakdown.
Algorithm of actions during repair
So, the algorithm of actions will be as follows:
- First, you need to unfasten the cover of the device to ensure that you can work with the internal mechanism.
- Then you need to remove the glass protection and light diffuser.
- Then you should unsolder the LED source from the matrix.
- And finally, solder it to a new, already operational crystal panel.
After carrying out the above steps, securely fasten each bolt and check the spotlight with a multimeter. If the test shows the working position, then the flashlight can be mounted in its original place and enjoy its operation. It is important to note that polarity must be observed when installing a new matrix.
In the same way, you can repair a 220-volt LED spotlight with your own hands. Beginners should also know that after troubleshooting is completed, they must proceed in the reverse order. By the way, it is possible to identify problems during operation by the following signs:
- flashing light;
- insulation violation;
- wire deformation;
- changing LED shades;
- dim burning.
Operating principle of LED spotlight
Often, during a breakdown, there is a desire to repair the LED spotlight yourself. However, first you need to know the nuances of the device. As a rule, the operation of the device is carried out due to the joint functioning of certain installed systems - optics, power supply, drivers and heat-sinking elements. Inside the case there are LEDs and small electronic elements. Voltage to the LED element converts current into light rays. As a result, the spotlight glows.
In conclusion
After making sure that the device is working and all its elements are functioning properly, you can improve it yourself. A 12-volt LED spotlight, for example, does not have a rectifier or stabilizer. Therefore, when repairing yourself, installing such devices is not so difficult. To do this, it is enough to connect pairs of LED sources in sequential action, which are switched on in a counter-current manner. Then attach a ballast capacitor to them. As you can see, repairing LED spotlights is not such a difficult task if you know the basic theory of their design.
