Diagram of a garland of 5 wires. If you need to fix a Chinese garland...

Instruction

Stock up on several garlands equipped with light bulbs with the same parameters. One of them will be a "donor" of lamps for the repair of the rest.

After disconnecting from the network, open the controller. See if any wires are unsoldered from the board. On one of its sides there are two contact points for connecting the power cord, on the other - five sites for connecting color channels. One of these sites is located away from the remaining four - the common wire of the channels is connected to it. Often, on the soldering to these sites of the conductors that have soldered off from them, the repair ends. When you're done with the controller, close it.

Some garlands are equipped with lamps that self-short when burned out. The lamp in which the shorting device has worked has a lower resistance than the good one, which is why the rest of the channel lamps operate in forced mode. Therefore, burned-out lamps in such a garland must be changed to serviceable ones as soon as possible. They can be taken from the "donor" garland. Replace by de-energizing the garland, carefully solder all connections and insulate with several layers of electrical tape.

If there are no shorting devices in the lamps, if one of them burns out, the entire channel goes out. It is clear that calling each of them separately will take a lot of time, so you have to use the iteration method. After turning off the power, cut the channel exactly in the middle. Ring the sections of the channel from the beginning to the middle and from the middle to the end. Now it is clear in which of them the burnt out lamp is located. This section can also be divided in half and ring both halves of it, and so on until the burnt out lamp is found. Replace it by taking a serviceable one also from the "donor" garland. After that, reconnect the wires in all the places where you cut them. Thoroughly solder and insulate the connections.

Light bulbs are a particular danger in a garland. When turned on, they instantly burn out, while between the thread holders, which are not isolated by anything, the full mains voltage begins to act. Such lamps should be replaced immediately with serviceable ones.

Never close a burnt out or bulb instead of replacing it with a new one, otherwise the remaining bulbs in the channel will be given increased voltage and burn out faster.

Repair of the LED garland is distinguished by two features. The first of them is that the new LED must be turned on in the same polarity as the other diodes of the same channel (a rectifier is installed in the controller of any garland). The second feature is the need to include a resistor in series with each of the LEDs. Its value should be the same as that of the resistors on the other diodes of the same garland. It is impossible to mix light bulbs and LEDs in the same garland, since the former usually have a rated current of 50 or 100 mA, and the latter - 20.

After completing the repair, before continuing to use the garland, be sure to carefully inspect it for the presence of uninsulated connections. Isolate them carefully.

We are all familiar with Christmas tree garlands, consisting of multi-colored light bulbs. However, in recent years, products based on led light-emitting diodes have become very popular.

How they are arranged, what connection scheme they have and what to do if the garland stops glowing, we will consider in detail in this article.

What is a Christmas tree garland made of?

What is a garland of LEDs, is it worse or better than usual?

Outwardly, this is almost the same product as before - wires, light bulbs (LED), control unit.

The most important element is of course the control unit. A small plastic box on which all kinds of backlight operation modes are indicated.

They change with the push of a button. The block itself can be with a fairly well protected level of moisture and dust protection IP44.

What does he have inside? To open it, use the sharp tip of a knife or a thin screwdriver to pry the latches from the bottom and take off the protective cover.

By the way, sometimes it is glued, and not just sitting on snaps.

First of all, inside you will see the wires soldered to the board. A thicker wire is usually a mains wire that supplies 220V.

Soldered on the board:

• controller that creates all the lighting effects

• thyristors, each of them goes to a separate channel of the garland

• resistors

• capacitor

• and diode bridges

The number of board elements depends primarily on the number of light channels of the garland. More expensive models may have a fuse.

Scheme of the LED garland

The mains alternating voltage through resistors and a diode bridge, already in a rectified form and smoothed through a capacitor, is supplied to the supply controller.

In this case, this voltage is supplied through the button, which is open in the normal state. When you close it, the controller modes switch.

The controller, in turn, controls the thyristors. Their number depends on the number of backlight channels. And after the thyristors, the output power goes directly to the LEDs in the garland.

The more such exits, the more diverse the color patterns the product can have. If there are only two of them, this means that only two parts (or halves) of the garland will work in different modes - some bulbs will go out, others will light up, etc.

In fact, these two lines of diodes will be connected via two channels in series. They will be connected to each other at the end point - the last LED.

If for some reason you are annoyed by the flashing of the garland and you want it to glow evenly with only one color, it is enough on the reverse side of the board to short-circuit the cathode and anode of the thyristor using soldering.

The more expensive garland you have at your disposal, the more outgoing channels and wires will leave the control board.

At the same time, if you follow the tracks of the board, one of the mains voltage leads is always supplied directly to the final LED of the garland, bypassing all the elements of the circuit.

Causes of the malfunction

Situations with malfunctions of the garland are very diverse.

At the same time, remember that the most important element - the microcircuit on the board, "burns" very, very rarely.

Approximately 5-10% of all cases.

• Bad contact on the wires

• LED in one of the bulbs

• Capacitor

• resistance

• One of the diodes

• One of the thyristors

• Controller chip

Bad soldering

If your backlight suddenly stops working, first of all, always check the soldering of the supply and outgoing wires. It is possible that the entire contact was held only by hot melt adhesive.

It is worth moving the wiring and contact anyway.

The most common problem with Chinese garlands is the use of very thin wires that simply break off at the solder points on the board.

To prevent this from happening, all contacts after soldering must be filled with a thick layer of hot melt adhesive.

And when stripping such veins, it is advised to use not a knife, but a lighter. Instead of chipping away the insulation with a blade, heat it up a bit and melt it with a lighter fire.

After that, simply remove the outer layer with your nails without damaging the cores themselves.

LED damage

If the wire contacts are in order and you sin on one of the diodes, how can you check its malfunction? And most importantly, how to find it among the whole series of light bulbs?

First of all, unplug the garland from the outlet. Start with the last diode. A power cable comes to it directly from the control unit.

An outgoing conductor is soldered to the same leg. It goes to the next branch of the light channel. You need to test the diode between its two power wires (input-output).

You will need a multimeter and its somewhat modernized probes.

To the tips of the probes of the tester, tightly wrap thin needles with a thread so that their tip protrudes a maximum of 5-8 mm.

From above, wrap everything with a dense layer of electrical tape.

Since the LEDs are soldered, just pulling them out of the light bulb as in ordinary garlands will not work here.

Therefore, you will have to pierce the insulation of the cores to get to the copper cores of the wiring. Switch the multimeter to the diode continuity mode.

And you begin to sequentially pierce the supply wires near each suspicious diode.

If your garland is not 220V, but 12V or 24V, which is connected from such a power supply:

then the working LED from the multimeter battery should light up.

If this is a 220V backlight, then check the readings of the multimeter.

On the working elements, they will be approximately the same, but the faulty one will show a break.

The method is certainly barbaric and damaging the insulation, but it is quite working. Truth street garlands after such punctures, it is better not to use it outdoors.

Chaotic blinking

There is a situation when you turn on the garland and it starts blinking randomly, then brighter, then dimmer. Changes channels by itself.

In general, one gets the impression that this is not some kind of factory effect, but as if the garland "has gone crazy."

The most common problem here is the electrolytic capacitor. It may swell a little, swell, and this will be clearly visible even to the naked eye.

Everything is solved by replacing it. The denomination is indicated on the case, so you can easily purchase and pick up a similar one in radio parts stores.

If you changed the capacitor, but this did not give an effect, where to look next? Most likely one of the resistors burned out (broken). Breakdown visually determine quite problematic. You will need a tester.

You take resistance measurements, having previously recognized its nominal (normal) value by marking. If it doesn't match, change it.

Part of the garland does not shine

When any of the channels on the garland does not work completely, there can be two reasons.

For example, a breakdown on one of the thyristors or diodes responsible for it.
To be sure of this, simply unsolder the wiring of this channel on the board from your place and connect the adjacent channel there, which is obviously working.

And if at the same time another channel also stops working, then the problem is not in the garland itself, but in the components of its board - a thyristor or diode.

Check them with a multimeter, find the right parameters and change them.

The garland shines dimly

There are also not quite obvious accidents, when the LEDs of a separate channel seem to be on, but rather dimly compared to the rest.

What does it mean? The controller circuit is working fine. When the button is pressed, all modes are switched.

Dialing by parameter tester diode bridge and resistance also does not reveal problems. In this case, it remains to sin only on the wires. They are already quite frail, and when such a stranded wire is torn, its cross section decreases even more.

As a result, the garland is simply not able to start the LEDs in the nominal brightness mode, since they simply do not have enough voltage. How to find this torn vein in a long garland?

To do this, you will have to walk along the entire line with the handles. Turn on the garland and start moving the wires near each LED until the entire backlight lights up in full force.

According to Murphy's law, this may be the very last segment of the garland, so be patient.

As soon as you find this area, pick up a soldering iron and disassemble the wires on the LED. Clean them with a lighter and re-solder everything.

Then isolate the place of soldering with heat shrink.

Among the many lighting fixtures used to decorate Christmas trees, a Chinese garland scheme occupies a special place. It, like all similar Chinese products, is simple and cheap. There is a lot of controversy about the reliability of such garlands, however, most consumers use them.

Scheme of a classic Chinese garland

This design is equipped with a smooth brightness control. For this, phase control is used, which regulates the opening angle of the thyristors. Automation uses as many as eight programs that provide a wide variety of control algorithms. Due to its qualities, the device is very cheap, and therefore diverges in millions of copies.

At the heart of the controller is a small board, where space is provided. There is also a microcontroller with four outputs. It is a small piece of genitax, where a microchip is attached using epoxy resin. Through the outputs of the microcontroller, with the help of current-limiting resistors, four thyristors are controlled. This device designed for anode voltage up to 600 volts and current in the range of 0.6-0.8 amperes. In separate designs of cheap garlands, instead of the input diode bridge, one diode remains. At the same time, the connection of the electrodes that control the thyristors is carried out directly to the outputs of the microcontroller, without limiting the current.

As a rule, the power of the microcontroller is very small, therefore, it is not able to control the operation of powerful triacs. In order to solve this problem, it is necessary to use a separate low-power power supply that is galvanically isolated from common network. For this purpose, you can use a low power adapter, for example, one that powers the amplifier television antenna containing a stabilizer in its circuit.

Other Ways to Solve Problems

To combine a low-power microcontroller with powerful triacs, the use of transistor switches is practiced, where transistors with a high current amplification factor are used. Thus, the Chinese garland circuit does not overload the outputs of the microcontroller. To ensure galvanic isolation, special microcircuits are used, the input of which contains an LED, and a low-power triac is installed at the output.

In order for the Chinese garland to work properly, it must be synchronized with the network using a signal. For this purpose, a phase is applied to the input of the microcontroller, with a nominal value of 220 volts through the installed resistor. The neutral wire of the network is connected to the common wire of the entire device.

Replacing the control unit of the Chinese garland

Unexpectedly, we managed to find out that the old garland, which had been decorating the Christmas tree for many years, no longer works, you should not rush to buy a new one, because there is always a chance to repair it yourself. As a rule, such Christmas tree lamps are not such a complicated design.

Therefore, if you carefully check for possible malfunctions, you can not wonder how to fix it. Chinese garland, the scheme of which is not difficult. So, if the contact wires came off in the garland, the light bulb burned out, or the mode switching was disturbed, then you should not throw it away. It is enough to use some effective tips.

The colors in the garland do not burn: what to do?

The most time-consuming breakdown is the one when the change of colors in the Chinese garland is disturbed. The scheme for solving the problem, if it is simple, then restoring the previous state of the device will not be easy. Violation of the color mode indicates that the bulbs in the corresponding section have burned out.

Before proceeding directly to the repair, it is recommended to disassemble the cover of the switch, which acts as a control unit, and check the reliability of the connections, especially the contacts soldered to the board.

Chinese garland repair: scheme

If at first glance there are no signs of a breakdown, then it means that it is safe to say that the light bulb has burned out. Modern Chinese garlands are arranged in such a way that all bulbs of the same color are connected in series. And if one of them burns out, the light on the entire electrical branch will go out. To fix the breakdown, you must use the Chinese LED garland circuit.

First you need to cut the garland into two equal parts and ring both sections. Then similar actions should be performed with the non-working side - cut into two halves and check again. Similar actions are carried out until it is possible to determine which of the bulbs is inoperative. It should be noted that this method is recommended to be used only if the electric Chinese garland, the circuit of which allows you to speed up the process, is not disassembled.

Methods for determining the malfunction

The process of restoring the health of the garland can be accelerated. To do this, you need to take a tester and attach needles to its ends instead of probes. Then, sequentially, with their help, punch through each of the sections of the chain so that the needle passes to the current core. It is necessary to determine where the section resistance differs significantly. In a similar way, you can determine the breakdown and repair it much faster, without making a lot of effort.

As a rule, the old Soviet garlands for the New Year tree are much more convenient in this regard than the Chinese garland. Their schemes are almost similar, but the design is noticeably different. In Soviet light bulbs are screwed into cartridges. Therefore, it is possible to determine which of them is in working condition, without a soldering iron and an ohmmeter, only by elimination. This method is that you should take a working light source and alternately screw it into the cartridges. Another way with the help of a tester is that it is necessary to measure the resistance of each individual lamp until you can find a burnt one.

Before trying to fix the garland, it is recommended to check the integrity of the common wire. For accuracy, you can refer to the scheme of the Chinese garland. On one side of the board, you can see 5 soldered wires, 4 of which are for glowing colors, and one is common. And if the common wire breaks, then it must be soldered.

What to do if the light does not turn on at all?

If, after studying the scheme of Chinese christmas garland, it was not possible to find the cause of its breakdown, it is recommended to make sure that the matter is not in the LEDs. In this case, check the control unit and power cord. First you need to make sure that the cord is intact, since there is a possibility that it was interrupted, or there was a break in the contact connections at the connection to the microcircuit. Then you need to try to check the reliability of the soldering of the contact connections to the board. Of course, in order not to suffer, you can purchase a new garland, however, if you want to fix the device, then you should act.

So, the control unit can be replaced with a starter from fluorescent lamp at 220 volts. First, it is recommended to check the connection of the LEDs. If the extreme elements of the groups are connected by anodes to each other, then it will be necessary to redo the circuit and connect the LEDs with cathodes. The point is that the voltage to the anode to normalize the operation of the starter must be supplied through a 5-watt resistor, while the resistance is 15-20 kOhm. In addition, additional diodes will need to be included in the circuit, which will pass through themselves reverse current networks. In this way, the LED Chinese garland is repaired at home.

As you can see, you will have to spend a lot of time and patience to repair the garland. Therefore, if it is not so expensive, it is recommended to simply replace it with a new, better one. It is important to note that if it was the LED that burned out, after which the operation of the entire section was disrupted, then the serviceable element should be soldered, strictly observing the polarity.

Broken light bulbs

If the light bulbs are broken and there is a desire to repair the device, then it is advisable to simply replace the damaged light source. It should be noted that the replacement is carried out only with the power turned off to avoid electric shock. In such situations, you should pay tribute to unbreakable light bulbs, since you do not always have to deal with malfunctions.

So, if it turns out that the garland does not work, then you should try visually and with the help of a tester to determine the problem area and cut it out. After that, the working sections must be connected using special connectors. On this repair can be considered completed.

Finally

As a rule, breaking a garland before the New Year is not always pleasant, but it is quite possible to repair the old one or purchase a new one. It is important to remember that for repairs you need to have special knowledge, for example, work with the board and change light bulbs. Therefore, in order not to lose nerves and time, it is recommended to buy a new New Year's garland.