LED flashlight repair DIY repair

The Chinese have learned how to make consumer goods and, in particular, flashlights. There is no such abundance of shapes, sizes, colors, perhaps, in any other group of products. There are at least five of them at home, but I bought another one. And not at all out of curiosity, I looked at it and my imagination drew a picture of how in the dark I turn on the side panel, attach it with the end part with a magnet to a metal garage door, and open the locks in the light, with my hands not busy. Service - "five stars"! But it was proposed to buy a lantern in a non-working condition.

• 6 LEDs (3 in reflector + 3 in side panel)
• 2 operating modes
• built-in memory
• magnet for fastening
• dimensions: 11x5x5 cm

Outwardly, an absolutely serviceable and attractive product did not create a luminous flux. Well, is it possible that such a wonderful thing was absolutely useless for nothing? This model was in a single copy, but the electronics lover in me "broadcast" that everything is surmountable.

The wire came off when the case was opened, but the plastic was already scorched and suggested that the electronic components of the charger circuit were burnt, and the battery could be quite serviceable.

And I started checking with it. The voltmeter showed the voltage at the terminals equal to one volt. Having already had some experience of dealing with such batteries, he began by opening the upper safety bar on it, removed the rubber caps, refilled each "jar" with one cube of distilled water and put it on charge. Charging voltage 12 V, current 50 mA.

Charging in high voltage mode (instead of the standard 4.7 V) lasted two hours, more than 4 volts were available.

Since the battery is serviceable, then it needs a charger assembled according to a more decent scheme and on more reliable electronic components than from a Chinese manufacturer, in which the input resistor "burned out", one of the two 1N4007 diodes of the rectifier was broken and smoked when turned on The charger is a resistor for the LED. First of all, you need a reliable capacitor of at least 400 volts, a diode bridge and a suitable zener diode at the output.

The compiled circuit showed its performance, a capacitor with a capacity of 1 μF and 400 V found MBGO (much more reliable and fits well into the intended case), the diode bridge is assembled from 4 pieces of 1N4007 diodes, the zener diode took the first imported one for testing (the stabilization voltage was determined by the prefix to multimeter, but its name could not be read).

Further, the circuit was assembled by soldering and used to produce a normal charge cycle of a previously discharged battery (milliammeter with a shunt, so in reality a complete deflection of the arrow occurs at a current of 50 mA). The zener diode is already used with a stabilization voltage of 5 V.

Printed circuit board for the final assembly of the charger with dimensions for the cell phone charging case. There is no better case here.

View of a really assembled, workable board. The capacitor body is glued to the board with “master” glue. But I was too lazy to poison a handkerchief, I blame, I accidentally found myself at hand a used one of practically the right size and this circumstance decided everything.

But I was not too lazy to replace the information sticker on the charging case. With a fully charged battery, in the dark, the side panel quite decently illuminates a room of 10 square meters. meters, and the light from the headlamp reflector makes objects clearly visible at a distance of up to 10 meters.

In the future, I propose to choose a more reliable and powerful battery for the flashlight. Posted by Babay from Barnaula.

After working for about a year, my LED Headlight XM-L T6 headlamp began to turn on every other time, or even turn off altogether without a command. Soon it stopped turning on completely.

The first thing I thought was the battery in the battery compartment.

The box itself is designed for 18650 lithium-ion batteries with a protection board. And I used batteries without protection and charged them with a Turnigy Accucell 6 universal charger (analogue of IMAX B6).

Therefore, I had to build up the contacts with a drop of solder. As you know, the solder alloy is soft and over time the soldering on the contact could wear out, and the connection with the battery could be broken.

But, after checking, it turned out that the cause of the malfunction lies not at all in poor contact, but in the electronic filling of the flashlight.

Any repair begins with diagnostics and disassembly. The lantern is easy to disassemble. We take out the lithium battery from the battery compartment. Next, unscrew the four screws.

There is a small printed circuit board under the battery tray.

There are only ten elements on the seal. The control function is performed by a miniature microcircuit in the SOT-23-6 package with the marking 819L 24 (U1). As it turned out, this is a microcircuit FM2819 - a specialized controller (not a driver!) For LEDs. Calling this microcircuit a driver somehow does not turn out to be a language.

This microcircuit supports four modes of LED control, including a strobe, which everyone wants to get rid of. Modes are switched cyclically by command from the tact button without latching.

If my flashlight had not broken, then I would not have known about the fourth SOS mode, which is activated by long pressing the button (about 3 seconds). When I bought, there were only three modes mentioned on the sell page.

When I began to study the datasheet on the FM2819, it turned out that this microcircuit supports four modes.

I will talk about the FM2819 microcircuit a little later, but for now let's figure out what the rest of the circuit elements are responsible for.

The yellow ceramic capacitor is soldered instead of the native one, which fell off when I disassembled the battery compartment. Judging by the photos of similar lamps, the capacitance of the capacitor, which is installed between the KEY terminal and the minus “-” of the power supply, can be within quite large limits. Mine had a 10pF (100) chip capacitor, and in other flashlights they can be soldered to 10nF (103) and 100nF (104), or even absent altogether.

The function of the power switch, which supplies the power supply voltage from the lithium battery to the high-power LED, is performed by the P-channel MOSFET FDS9435A in the SO-8 package. The photo shows that there is an abbreviated marking on its body. 9435A.

The plus of the power supply from the drain of the FDS9435A transistor is supplied to the powerful LED not directly, but through three current-limiting resistors (R200 - 0.2 Ohm; R500 - 0.5 Ohm; 2R0 - 2 Ohm). They are connected in parallel. Their total resistance is less than the smallest resistance in the circuit (i.e. less than 0.2 ohms). If you count, then it is equal to 0.13 ohms.

I talked about how to connect resistors and calculate their total resistance here.

To illuminate the rear LED HEADLIGHT indicator, a conventional red SMD LED is used. It is marked as LED on the board. It illuminates a white plastic plate.

Since the battery compartment is located on the back of the head, such an indicator is clearly visible at night.

Obviously it will not interfere with cycling and walking along roadways.

Through a 100 Ohm resistor, the positive lead of the red SMD LED is connected to the drain of the FDS9435A MOSFET. Thus, when the flashlight is turned on, voltage is supplied to both the main Cree XM-L T6 XLamp LED and a low-power red SMD LED.

We figured out the main details. Now I'll tell you what broke.

When I pressed the button to turn on the flashlight, I could see that the red SMD LED starts to shine, but it is very dim. The operation of the LED corresponded to the standard operating modes of the flashlight (maximum brightness, low brightness and strobe). It became clear that the control microcircuit U1 (FM2819) is most likely working properly.

Since it regularly responds to pressing a button, then, perhaps, the problem lies in the load itself - a powerful white LED.Having unsoldered the wires going to the Cree XM-L T6 LED and connected it to a homemade power supply, I made sure it was working properly.

Then I decided to measure the voltage on the board itself in order to find out where the precious volts from the battery were lost.

When measuring, it turned out that in the maximum brightness mode, the drain of the FDS9435A transistor is only 1.2V. Naturally, this voltage was not enough to power the powerful Cree XM-L T6 LED, but the red SMD LED was enough to make its crystal glow dimly.

It became clear that the FDS9435A transistor, which is used in the circuit as an electronic key, is faulty.

I didn't pick anything up to replace the transistor, but bought the original P-channel PowerTrench MOSFET FDS9435A from Fairchild. Here is its appearance.

As you can see, this transistor has full markings and the Fairchild distinctive mark (F) that produced this transistor.

Comparing the original transistor with the one installed on the board, the thought crept into my head that a fake or less powerful transistor was installed in the lantern. Perhaps even marriage. Still, the lantern did not have time to serve even a year, and the power element had already “thrown back its hooves”.

The pinout of the FDS9435A transistor is as follows.

As you can see, there is only one transistor inside the SO-8 case. Conclusions 5, 6, 7, 8 are combined and are the outlet of the drain (Drain). Pins 1, 2, 3 are also connected together and are the source (Source). The 4th pin is the gate (Gate). It is to him that the signal comes from the FM2819 (U1) control microcircuit.

As a replacement for the FDS9435A transistor, you can use APM9435, AO9435, SI9435. All these are analogs.

You can evaporate the transistor using both the usual methods and more exotic ones, for example, the Rose alloy. You can also use the brute force method - cut the leads with a knife, dismantle the case, and then unsolder the leads remaining on the board.

After replacing the FDS9435A transistor, the headlamp began to work properly.

This concludes the story about the repair. But if I hadn't been a curious radio mechanic, I would have left everything as it is. It works and okay. But I was haunted by some moments.

Since initially I did not know that the microcircuit labeled 819L (24) is FM2819, armed with an oscilloscope, I decided to see what signal the microcircuit sends to the gate of the transistor under different operating modes. It’s interesting.

When the first mode is turned on, -3.4 is applied to the gate of the FDS9435A transistor from the FM2819 microcircuit. 3.8V, which practically corresponds to the voltage on the battery (3.75. 3.8V). Naturally, a negative voltage is applied to the gate of the transistor, since it is a P-channel.

In this case, the transistor fully opens and the voltage across the Cree XM-L T6 LED reaches 3.4. 3.5V.

In the mode of minimum luminescence (1/4 brightness), about 0.97V comes to the FDS9435A transistor from the U1 microcircuit. This is if you take measurements with an ordinary multimeter without bells and whistles.

In fact, in this mode, a PWM signal (pulse width modulation) comes to the transistor. Having connected the oscilloscope probes between the “+” of the power supply and the gate terminal of the FDS9435A transistor, I saw this picture.

Picture of a PWM signal on the oscilloscope screen (time / division - 0.5; V / division - 0.5). Sweep time - mS (milliseconds).

Since a negative voltage is applied to the gate, the “picture” on the oscilloscope screen is inverted. That is, now the photo in the center of the screen shows not an impulse, but a pause between them!

The pause itself lasts about 2.25 milliseconds (mS) (4.5 divisions of 0.5mS). At this moment, the transistor is closed.

The transistor then turns on 0.75 mS. This applies voltage to the XM-L T6 LED. The amplitude of each pulse is 3V. And, as we remember, I measured only 0.97V with a multimeter. This is not surprising, since I measured a constant voltage with a multimeter.

This moment is on the oscilloscope screen. The time / division switch was set to 0.1 to better determine the pulse width. The transistor is open. Do not forget that a minus “-“ comes to the shutter. The impulse is reversed.

Now you can calculate the duty cycle (S).

S = (2.25mS + 0.75mS) / 0.75mS = 3mS / 0.75mS = 4. Where,

S - duty cycle (dimensionless value);

Τ - repetition period (milliseconds, mS). In our case, the period is equal to the sum of the switch-on (0.75 mS) and the pause (2.25 mS);

τ - pulse duration (milliseconds, mS). We have it 0.75mS.

You can also define fill factor (D), which in the English-speaking environment is called Duty Cycle (often found in all kinds of datasheets for electronic components). It is usually indicated as a percentage%.

D = τ / Τ = 0.75 / 3 = 0.25 (25%). Thus, in the dimmed mode, the LED is on for only a quarter of the period.

When I did the calculations for the first time, my fill factor came out to be 75%. But then, when I saw a line about 1/4 brightness in the datasheet on FM2819, I realized that I had screwed up somewhere. I just confused the pause and the pulse width in places, because out of habit I took the minus “-” on the shutter for the plus “+”. Therefore, it turned out the opposite.

In the “STROBE” mode, I could not see the PWM signal, since the oscilloscope is analog and quite old. I failed to synchronize the signal on the screen and get a clear image of the impulses, although it was obvious that it was there.

Typical switching circuit and pinout of the FM2819 microcircuit. Maybe someone will come in handy.

Some moments associated with the operation of the LED did not give me rest. Before, I somehow didn’t deal with LED lights, but then I wanted to figure it out.

When I looked through the datasheet for the Cree XM-L T6 LED, which is installed in the flashlight, I realized that the current-limiting resistor is too small (0.13 Ohm). Yes, and on the board one seat for the resistor was free.

When I was surfing the Internet in search of information about the FM2819 microcircuit, I saw a photo of several printed circuit boards of similar lamps. Some of them had four 1 Ohm resistors soldered, and some of them even had an SMD resistor marked “0” (jumper), which, in my opinion, is generally a crime.

An LED is a non-linear element, and therefore a current-limiting resistor must be connected in series with it.

If you look into the datasheet for LEDs of the Cree XLamp XM-L series, you will find that their maximum supply voltage is 3.5V, and the nominal 2.9V. In this case, the current through the LED can reach 3A. Here is a graph from the datasheet.

The rated current for such LEDs is considered to be 700 mA at 2.9V.

Specifically, in my flashlight, the current through the LED was 1.2 A with a voltage across it of 3.4. 3.5V, which is clearly a bit too much.

To reduce the forward current through the LED, I soldered four new 2.4 Ohm resistors (frame size 1206) instead of the old resistors. Received a total resistance of 0.6 ohms (power dissipation 0.125W * 4 = 0.5W).

After replacing the resistors, the forward current through the LED was 800 mA at a voltage of 3.15V. This way the LED will work in a milder thermal mode, and hopefully will last a long time.

Since resistors of size 1206 are designed for a power dissipation of 1 / 8W (0.125 W), and in maximum brightness mode, about 0.5 W of power is dissipated on four current-limiting resistors, it is advisable to remove excess heat from them.

To do this, I cleaned the copper polygon next to the resistors from the green varnish and soldered a drop of solder onto it. This technique is often used on printed circuit boards of consumer electronics equipment.

After finalizing the electronic filling of the flashlight, I covered the printed circuit board with PLASTIK-71 varnish (electrical insulating acrylic varnish) to protect it from condensation and moisture.

When calculating the current limiting resistor, I ran into some subtleties. The voltage at the drain of the MOSFET of the transistor should be taken as the supply voltage of the LED. The fact is that on the open channel of the MOSFET transistor, part of the voltage is lost due to the channel resistance (R_{(ds) on}).

The higher the current, the more voltage “settles” along the Source-Drain path of the transistor. For me, at a current of 1.2A, it was 0.33V, and at 0.8A - 0.08V. Also, part of the voltage drops on the connecting wires that go from the battery terminals to the board (0.04V). It would seem such a trifle, but in total it runs up 0.12V. Since under load, the voltage on the Li-ion battery sags to 3.67. 3.75V, then the MOSFET's drain is already 3.55. 3.63V.

Another 0.5. 0.52V extinguishes a circuit of four parallel resistors. As a result, a voltage in the region of 3 with a small volt comes to the LED.

At the time of this writing, an updated version of the reviewed headlamp is on sale.It already has a built-in charge / discharge control board for a Li-ion battery, as well as an optical sensor that allows you to turn on the flashlight with a palm gesture.

An electric flashlight refers, as it were, to an additional auxiliary tool for carrying out any work in the presence of poor lighting or no lighting at all. Each of us chooses the type of flashlight at our discretion:

• Head Torch;
• pocket flashlight;
• hand-held flashlight

etc.

The electrical diagram of a simple flashlight in Fig. 1 consists of:

• battery cells;
• light bulbs;
• key switch.

The scheme in its execution is simple and does not require explanations in this regard. The reasons for the malfunction of the flashlight with this scheme can be:

• oxidation of contact connections with batteries;
• oxidation of the contacts of the bulb holder;
• oxidation of the contacts of the bulb itself;
• malfunction of the light switch key;
• a malfunction of the light bulb itself, the light bulb has burned out;
• lack of contact connection with the wire;
• lack of battery power.

Other reasons for the malfunction may be any mechanical damage to the body of the flashlight.

headlamp with LED BL - 050 - 7C

The BL - 050 - 7C flashlight comes on sale with a built-in charger; when such a flashlight is connected to an external AC voltage source, the battery is recharged.

Rechargeable batteries, or rather electrochemical accumulators, - the principle of charging such cells is based on the use of reversible electrochemical systems. Substances formed during the discharge of the battery under the influence of an electric current are able to restore their original state. That is, we recharged the flashlight and can continue to use it. Such electrochemical batteries or individual cells can consist of a certain amount, depending on the voltage consumed:

• the number of bulbs;
• type of bulbs.

The number, the set of such individual elements of the flashlight, is a battery.

The electrical circuit of the flashlight in Fig. 2 can be considered both consisting of a simple incandescent light bulb and a certain number of LED bulbs. For any flashlight circuit, what exactly is important? - It is important that the energy consumed by the light bulbs in the electrical circuit - corresponds to the output voltage of the power source of the battery, consisting of individual cells.

Resistor R1 with a resistance of 510 kΩ and a rated power of 0.25 W in the electrical circuit is connected in parallel, due to this large resistance, the voltage in the further section of the electrical circuit is significantly lost, or rather, part of the electrical energy is converted into thermal energy.

With a resistor R2 with a resistance of 300 ohms and a nominal power of 1 W, current flows to the VD2 LED. This LED serves as an indicator light to indicate the connection of the flashlight charger to an external AC voltage source.

The current is supplied to the anode of the diode VD1 from the capacitor C1. The capacitor in the electrical circuit is a smoothing filter, part of the electrical energy is lost with a positive half-cycle of the sinusoidal voltage, since during this half-cycle the capacitor is charged.

With a negative half-cycle, the capacitor is discharged and the current flows to the anode of the cathode VD1. An external voltage drop for a given electrical circuit occurs when there are two resistors and a light bulb in the electrical circuit. Also, it can be taken into account that when the current passes from the anode to the cathode - in the VD1 diode - there is also its own potential barrier. That is, it is also common for a diode to undergo heating to some extent, at which an external voltage drop occurs.

On the GB1 battery, which consists of three cells, a current of two potentials + - is supplied from the charger when the flashlight is connected to an external source of alternating voltage. In the battery, the electrochemical composition of the battery is restored to its original state.

The following diagram in Fig. 3, which is found in LED flashlights, consists of the following electronic elements:

• two resistors R1; R2;
• diode bridge consisting of four diodes;
• capacitor;
• diode;
• LED;
• key;
• batteries;
• light bulbs.

For a given circuit, the external voltage drop occurs due to all the constituent elements of the electronics - connected in this circuit. One diagonal of the diode bridge of the bridge circuit is connected to an external AC voltage source, the other diagonal of the diode bridge is connected to the load - consisting of a certain number of light-emitting diodes.

All detailed descriptions on replacing electronics elements when repairing a flashlight, as well as diagnosing these elements - you can find on this site, which contains similar topics in which repair of household appliances is seen.

For my work, I sometimes have to use a headlamp. Approximately six months after the purchase, the flashlight's rechargeable battery stopped charging after it was turned on for recharging via the power cord.

When establishing the cause of the headlamp breakdown, the repair was accompanied by photographs in order to present this topic in an illustrative example.

The cause of the malfunction was not clear at the beginning, since when the flashlight was switched on for recharging, the signal light came on and the flashlight itself, when the switch button was pressed, emitted a weak light. So what could be the reason for such a malfunction? Is the battery malfunctioning or some other reason?

It was necessary to open the body of the flashlight to inspect it. On the photographs of photo # 1, the screwdriver tip indicates the places where the body connection is fastened.

If the body of the flashlight cannot be opened, you need to carefully inspect to see if all the screws have been removed.

Photo # 2 shows a buck converter in both voltage and current.

In the circuit, you should not look for the cause of the malfunction, since when connected to an external source - the signal light glows photo No. 2 red LED light. We check further connections.

In front of us in the photo # 3 shows the light switch of the LED flashlight. The contacts of the push-button post of the switch are a double light switch device, where, for this example, light up:

• six LED lamps,
• twelve LED bulbs

flashlight. Two contacts of the switch, as we can see, are short-circuited and a common wire is soldered to these contacts. Two wires are soldered to the next two contacts of the switch - separately, from which the current flows to the lighting:

When switching, it is enough to check the contacts of the light switch with a probe as shown in photo # 4. We touch the common contact with two short-circuited contacts with a finger and alternately touch the other two contacts with a probe.

If the switch is in good working order, the LED lamp of the probe lights up photo # 4. The light switch is serviceable, we carry out further diagnostics.

The power cord can also be checked here with a photo # 5 probe. To do this, with your finger, you need to short-circuit the pins of the plug and alternately connect the probe to the first and second contacts of the cable connector. If the probe light comes on, there is no break in the power cord.

The power cord for recharging the battery is working properly, we carry out further diagnostics. You should also check the flashlight battery.

On the enlarged image of the storage battery, photo # 6, it can be seen that a constant voltage of 4 Volts is supplied to recharge it.The current strength of this voltage is - 0.9 ampere hour. We check the battery.

The multimeter in this example is set to a DC voltage measuring range of 2 to 20 Volts so that the measured voltage matches the specified range.

As we can see, the display of the device shows the constant voltage of the battery - 4.3 Volts. In fact, this indicator should take on a greater value - that is, there is insufficient voltage to power the LED lamps. LED lamps take into account the potential barrier for each such lamp, as we know from electrical engineering. Consequently, the battery does not receive the required voltage when recharging.

And here is the whole reason for the malfunction of photo # 8. This cause of the malfunction was not immediately established - in the break of the contact connection of the wire with the battery.

The wires in this scheme are unreliable for soldering, since the thin section of the wire does not allow them to be securely fastened at the soldering point.

But even this cause of breakdown is removable, the wiring was replaced with a more reliable section and the LED flashlight is currently operational, it works flawlessly.

I consider the presented topic unfinished, they will be given in examples for you - repairs of other types of flashlights.

I would call it "Notes of a Shitty Electrician"! The author simply does not understand how the circuit works, its elements, he confuses the concepts. Using the example of the operation of the circuit in Fig. 2: R1 serves to discharge the capacitor C1 after disconnecting the flashlight from the mains for safety reasons. There is no "loss" of voltage "in the further section", let the Author connect a voltmeter and look at it to make sure of this. Resistor R2 serves as a current limiter. The VD2 LED serves not only as an indicator, but also supplies a positive potential to the + battery.
Capacitor C1 in this circuit is a damping (and not a smoothing filter), so it is on it that the excess AC voltage is extinguished.
About the potential barrier, too, heap it up - it's ridiculous to read. And the current "current of two potentials" ?! According to classical physics, current flows from positive to negative potential, and electrons move in reverse.
Did the author go to school?
And he has this everywhere. Sad. But someone takes his "revelations" at face value.

Hello povaga! I stopped charging the "Oblic 2077" flashlight on one LED. I can’t find the schemes, but it’s something like in figure 3. Difference: there is no capacitor C2, diode VD5, two resistors and a three-pin board are soldered to the SA1 switch. I measured the voltage after the bridge - 2 volts, the battery is 4 volts, how can it be charged? Please help with the operation diagram and electrical circuit. Thanks in advance, Regards, Doldin.

Hello Mikhail. That is, you measured the voltage at the output of the bridge circuit and your measuring device shows 2 volts, - of course, this is not enough to charge the battery. You need to check the resistors (for resistance) and the rest of the electronics that are located on the board, or you can give it to a workshop for checking - the circuit board and resistors, and get advice there (on replacing one or another part).
Victor.

Hello Victor! 2 volts after the bridge is when the load is completely disconnected, only the HL1 power-on indicator is connected. R1 = 560 KOhm, C1 = 105J, I checked the resistor - a whole one and a capacity of about 1 μF. How to increase the voltage after the bridge? Is there an electrical circuit "Oblique 2077", or tell me where to find it? Best regards, Doldin.

Hello, I have a flashlight "Era" well, and in the back on the glued tag it says FA 18 E, 182W - 1500614, the trouble is that when I inadvertently used the wrong charger instead of 6 volts, I did not charge, disassembled on the diagram, the resistor is charred or otherwise the resistance, if you know then tell me what is the resistance on this flashlight

Hello Nikolay. If the resistor is charred, you need to check the rest of the electronics, such as the capacitor and diodes. There are two diodes, if I'm not mistaken. They could also lose their current conduction properties. You'd better take this small circuit for repair to fix the malfunction. If an electrical circuit with the nominal values ​​of the electronic elements in the "Flashlight Operation Manual" was attached, then there would be no problems with the elimination of the malfunction.
Victor.

Hello, help me assemble the flashlight as in photo # 2, my brother repaired the button and tore off the wiring, we cannot assemble the circuit if you can give pictures in details of where to solder.

Hello Valery. As soon as I have free time, I will immediately answer your question (on the wire connections in the flashlight circuit). The topic will have a title: “How to assemble a flashlight. Photo and description ".
Victor.

Hello Valery. I told you the name of the topic, the topic will be published today.
Victor.

How to connect the wiring of an escaped flashlight as in photo # 2, you need a diagram, please.

Fired two resistances R1 R2 in the ERA FA35M lamp. Please tell me their data to replace.

Hello. I did not find data on the resistance of two resistors for your flashlight on the Internet. Try to go to a store that sells electronics parts to a sales consultant. I believe that the sales consultant will be able to select resistors by resistance.

Chinese headband oytventyre no screws please tell me how to open

Hello. I believe that it is impossible to open a flashlight with a stamping design.

Often there is no contact on the retractable plug for charging the flashlight. It is necessary to disassemble and bend the contacts.

Good afternoon. I inserted the wrong batteries, the flashlight blinked and that's it, is there a chance to repair it?

Hello. Of course, there is an opportunity to repair the flashlight. You need to ring the circuit and determine the cause of the malfunction.

• DIY LED lamp repair
• Features of repairing LED lights
• What are the malfunctions of LED lights
• What you need to repair LED lights

Every car owner tries to tune his car in some way. In particular, this applies to headlights, backlights, that is, everything related to the light in the car. The most common option is to install LEDs. But these lamps have their own characteristics, including those related to operation and repair.

LEDs are somewhat universal - a combination of quality and functionality. From a practical point of view, it is LEDs and xenon headlights that are rivals. Someone gives preference to the first option, and someone to the second. It cannot be denied that LED optics are stronger due to the fact that the light diverges in a beam, but outwardly this option looks more stylish, moreover, the oncoming driver will not be blinded by such light. The disadvantages of this lighting method should also be mentioned. LED lamps are equipped with a rather sophisticated cooling system.

Although LED lamps are positioned as very durable, many motorists complain about interruptions in work. For example, after 2 - 3 months after installing the LEDs in the car, the lamps may start blinking. What to do in this case? First, you need to understand how LED bulbs work. These lamps need to be given a current of as much current as the manufacturer specifies. Less, but no more.

Therefore, along with the light strips, it is necessary to install a device that stabilizes the current. That is, when the lighting fails, this device will have to be checked. Also, to repair LED lamps, you need to understand how they are installed. It's electricity, you have to be careful with it.

Now let's deal specifically with the reasons why LED lamps stop burning. There may be several reasons. If a light bulb just burns out, then often it is simply replaced with a new one. Many car owners who have installed LEDs instead of incandescent lamps, some time after the start of operation, begin to notice that the lights flash from time to time. The first thought at the sight of such "action" is the wrong installation of LED lamps. But this is only relevant if you carried out the installation yourself.

In order to check the correct installation of the diodes, take those standard lamps that were previously installed, install them in place and check the reaction. If the standard lamps burn normally without flickering, then everything is in order with the wiring. It has already been said that a current stabilizer is installed along with the LEDs.

Often, a resistor acts as a stabilizer. So there can be problems with him. In order to check its operation, disassemble the lighting device. Different diodes have different resistors, often with a resistance of 390 - 560 ohms... As things stand, the declared power will not be enough for normal lighting. But the voltage in the on-board network of the car often jumps, so it is not always possible to install 12V there. In order to prevent LED damage due to these inconsistencies, you need to take a few simple steps that should eliminate the flickering of the lamps.

Disassemble the diode. You will need to use its base. Prepare a more powerful resistor (860 - 1000 Ohm) and insert into the base. Connect the lamp to the system. It should work smoothly. If you inserted a light bulb, and it still did not light up, then it is worth checking the fuses. The problem may be in the soldering on the plinth. If it is smaller than on a regular light bulb that was on before, then the LED will light up only if you press it.

If you let go of the lamp, it will spring upward, which will break the connection. Also, LED strips may stop working due to thermal degradation. This happens if the heat from the lamps is not completely removed.

Also, do not forget about the wiring itself. Under the influence of the same heat or due to simple mechanical damage, some small wiring may not conduct current, that is, the lamps will not burn. You can rashly run to the store for new tapes, but after installing them you will still see that there is no reaction from the lamps. Then it is worth carefully examining the wiring - suddenly somewhere the insulation is broken or the wire is clamped. Based on the reason, you should choose a way to repair LED lighting.

To repair car LEDs, you will need a special set of tools and materials used to repair car wiring:

- a set of wires with a cross-section of the corresponding diameter

- wires to the terminals to check for a spark on the candles

- indicator for checking the wiring for a break

All this will have to be stocked up, because otherwise it will be more difficult for you to determine the cause of the breakdown. LEDs are a unique invention, but they require attention. Therefore, do not leave your car lighting repairs for later.

How to fix your LED Chinese pocket flashlight yourself. DIY LED lights repair instructions with visual photos and videos

Today we are going to talk about how to fix an LED Chinese pocket flashlight by yourself. We will also consider instructions for repairing LED lights with our own hands with visual photos and videos

As you can see, the scheme is simple. The main elements: a current-limiting capacitor, a rectifier diode bridge on four diodes, a battery, a switch, super-bright LEDs, an indication LED of the flashlight battery charging.

Well, now, in order, about the purpose of all the elements in the flashlight.

Current limiting capacitor.It is designed to limit the charging current of the battery. Its capacity may vary for each type of flashlight. A non-polar mica capacitor is used. The operating voltage must be at least 250 volts. In the circuit, it must be shunted, as shown, with a resistor. It serves to discharge the capacitor after you unplug the flashlight from the charger. Otherwise, you may get an electric shock if you accidentally touch the 220 volt mains terminals of the flashlight. The resistance of this resistor must be at least 500 kOhm.

The rectifier bridge is assembled on silicon diodes with a reverse voltage of at least 300 volts.

A simple red or green LED is used to indicate that the flashlight battery is charging. It is connected in parallel with one of the rectifier bridge diodes. True, in the diagram, I forgot to indicate the resistor connected in series with this LED.

It makes no sense to talk about the rest of the elements, so everything should be clear anyway.

I would like to draw your attention to the main points of repairing an LED flashlight. Consider the main malfunctions and how to fix them.

1. The flashlight stopped shining. There are not so many options here. The reason may be the failure of super-bright LEDs. This can happen, for example, in the following case. You put the flashlight on charge and accidentally turned on the switch. In this case, a sharp current surge will occur and one or more diodes of the rectifier bridge may be punctured. And behind them, the capacitor may not be able to withstand it and will close. The battery voltage will rise sharply and the LEDs will fail. So, in any case, do not turn on the flashlight when charging, if you do not want to throw it away.

2. The flashlight does not turn on. Well, here you need to check the switch.

3. The flashlight runs out very quickly. If your flashlight is "experienced", then most likely the battery has worked out its service life. If you actively use the flashlight, then after one year of operation, the battery no longer holds.

Problem 1. LED flashlight does not turn on or flickers during operation

This is usually the reason for poor contact. The easiest treatment is to tighten all threads tightly.
If the flashlight doesn't work at all, start by checking the battery. Perhaps it is discharged or out of order.

Unscrew the back cover of the lamp and use a screwdriver to close the housing with the negative contact of the battery. If the flashlight lights up, then the problem is in the module with the button.

90% of the buttons of all LED lights are made according to the same scheme:
The button body is made of aluminum with a thread, a rubber cap is inserted there, then the button module itself and a pressure ring for contact with the body.

The problem is most often solved in a loosely clamped pressure ring.
To eliminate this malfunction, it is enough to find round-nose pliers with thin stings or thin scissors that need to be inserted into the holes, as in the photo, and turned clockwise.

If the ring moves, then the problem has been fixed. If the ring is in place, then the problem lies in the contact of the button module with the body. Unscrew the retaining ring counterclockwise and pull the button module outward.
Often poor contact occurs due to oxidation of the aluminum surface of the ring or rim on the printed circuit board. Indicated by arrows)

It is enough just to wipe these surfaces with alcohol and the functionality will be restored.

Button modules are different. Some in which the contact goes through the printed circuit board, others, in which the contact goes through the side lobes to the body of the lantern.
Just bend such a petal to the side so that the contact is tighter.
Alternatively, you can solder tin to make the surface thicker and press the contact better.
All LED lights are basically the same.

The plus goes through the positive terminal of the battery to the center of the LED module.
The minus goes through the body and closes with a button.

It will not be superfluous to check the tightness of the LED module inside the case. This is also a common problem with LED lights.

Using round nose pliers or pliers, rotate the module clockwise until it stops. Be careful, it is easy to damage the LED at this point.

These actions should be enough to restore the functionality of the LED flashlight.

It is worse when the flashlight works and the modes are switched, but the beam is very dim, or the flashlight does not work at all and there is a burning smell inside.

Problem 2. The flashlight works fine, but dimly, or does not work at all and there is a burning smell inside

Most likely the driver is out of order.
The driver is a transistorized electronic circuit that controls the flashlight modes and is also responsible for a constant voltage level, regardless of the battery discharge.

You need to unsolder the burned-out driver and solder a new driver, or connect the LED directly to the battery. In this case, you lose all modes and remain only with the maximum.

Sometimes (much less often) the LED fails.
This can be verified very simply. bring the voltage 4.2 V / to the contact pads of the LED. The main thing is not to mix up the polarity. If the LED is on brightly, then the driver is out of order, if on the contrary, then you need to order a new LED.

Unscrew the LED module from the case.
Modules are different, but usually they are made of copper or brass and

The weakest point of such lights is the button. Its contacts are oxidized, as a result of which the flashlight begins to shine dimly, and then it may stop turning on altogether.
The first sign is that a flashlight with a normal battery shines weakly, but if you click the button several times, the brightness increases.

The easiest way to make such a lantern shine is to do the following:

1. Take a thin stranded wire, cut off one vein.
2. We wind the wiring on the spring.
3. Bend the wire so that the battery does not break it. The wire should protrude slightly
over the swirling part of the flashlight.
4. Tighten tightly. We break off the excess wire (tear off).
As a result, the wire provides good contact with the negative part of the battery and the flashlight.
will shine with due brightness. Of course, the button with such a repair is not a lot, therefore
turn on - turn off the flashlight by turning the head part.
My Chinese man worked like this for a couple of months. If you need to change the battery, the back of the flashlight
should not be touched. We turn our head away.

RESTORING THE PERFORMANCE OF THE BUTTON.

Today I decided to bring the button back to life. The button is in a plastic case, which
simply pressed into the back of the lantern. In principle, it can be pushed back, but I did it a little differently:

1. Make a pair of holes with a 2 mm drill bit to a depth of 2-3 mm.
2. Now you can unscrew the housing with the button with tweezers.
3. We extract the button.
4. The button is assembled without glue and latches, so it is easy to disassemble it with a stationery knife.
The photo shows that the movable contact has oxidized (round bullshit in the center, like a button).
You can clean it with an eraser or fine sandpaper and put the button back together, but I decided to additionally irradiate this part and the fixed contacts.

1. We clean with fine sandpaper.
2. We serve with a thin layer the places marked in red. We wipe the flux with alcohol,
collecting the button.
3. To increase reliability, I soldered the spring to the bottom contact of the button.
4. Putting everything back.
After renovation, the button works fine. Of course, tin also oxidizes, but since tin is a rather soft metal, I hope that the oxide film will be
easy to break down. It is not for nothing that the central contact on the bulbs is made of tin.

What is "hotspot", my Chinese person was very vague, so I decided to enlighten him.
We unscrew the head part.

1. The board has a small hole (arrow).With the help of an awl, we unscrew the filling,
at the same time, lightly press your finger on the glass from the outside. This makes it easier to get out.
2. Remove the reflector.
3. Take ordinary office paper, punch 6-8 holes with an office punch.
The hole diameter of the hole punch perfectly matches the diameter of the LED.
Cut out 6-8 paper washers.
4. Place the washers on the LED and press down with the reflector.
Here you have to experiment with the number of pucks. In this way, I improved the focusing of a pair of flashlights, the number of washers was in the range of 4-6. It took 6 of them on the current patient.

INCREASE BRIGHTNESS (for those who know a little about electronics).

The Chinese save on everything. A couple of unnecessary details - an increase in the cost price, so they do not put it.

The main part of the diagram (marked in green) can be different. On one or two transistors or on a specialized microcircuit (I have a circuit of two parts:
choke and microcircuit with 3 legs, similar to a transistor). But on the part marked in red - they save. I added a capacitor and a pair of 1n4148 diodes in parallel (I didn't find a Schottky). The brightness of the LED has increased by 10-15 percent.

1. This is how the LED looks like in similar Chinese. From the side you can see that there are thick and thin legs inside. A thin leg is a plus. You need to navigate on this basis, because the colors of the wires can be completely unpredictable.
2. This is how the board looks like, to which the LED is soldered (on the back side). Foil is marked in green. The wires from the driver are soldered to the LED legs.
3. Cut the foil on the plus side of the LED with a sharp knife or a triangular file.
We sand the entire board to remove the varnish.
4. Solder diodes and capacitor. I took the diodes from a broken computer power supply, the tantalum capacitor dropped out of some burned-out hard drive.
The positive wire now needs to be soldered to the pad with diodes.

As a result, the flashlight gives out (by eye) 10-12 lumens (see photos with hotspots),
judging by the phoenix, which produces 9 lumens in the minimum mode.