20.06.2023
Do-it-yourself repair and modernization of Lentel, Photon, Smartbuy Colorado and RED LED lights. Electrical circuits of flashlights
Any electrical device can break down. This also applies to LED lights.
The online store provides a guarantee of up to 3 months on everything.
All lanterns are checked upon receipt and again upon sale.
In most cases, lamp repair is quite affordable to an ordinary person with a standard set of tools.
In 90% of cases, all breakdowns occur due to poor contact in the flashlight circuit.
Problem 1. The LED flashlight does not turn on or flickers during operation
As a rule, this is the cause of poor contact. The easiest way to treat it is to tighten all the threads tightly.
If the flashlight doesn't work at all, start by checking the battery. It may be discharged or damaged.
Unscrew back cover flashlight and use a screwdriver to connect the housing to the negative terminal 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 by a loose clamping ring.
To fix this problem, just find round pliers with thin tips or thin scissors that need to be inserted into the holes, as in the photo, and turned clockwise.
If the ring moves, the problem is fixed. If the ring stays in place, then the problem lies in the contact of the button module with the body. Unscrew the clamping ring counterclockwise and pull the button module out.
Poor contact often occurs due to oxidation of the aluminum surface of the ring or border on the printed circuit board (indicated by arrows)
Simply wipe these surfaces with alcohol and functionality will be restored.
Button modules are different. Some have contact through the printed circuit board, others have contact through the side petals to the flashlight body.
Just bend this petal to the side so that the contact is tighter.
Alternatively, you can make a solder from tin so that the surface is thicker and the contact is pressed better.
All LED lights are basically the same
The plus goes through the positive contact of the battery to the center of the LED module.
The negative goes through the body and is closed with a button.
It would be a good idea to check the tightness of the LED module inside the housing. 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 quite enough to restore the functionality of the LED flashlight.
It’s worse when the flashlight works and the modes are switched, but the beam is very dim, or the flashlight doesn’t work at all and there’s a burning smell inside.
Problem 2. The flashlight works fine, but is dim or does not work at all and there is a burning smell inside
Most likely the driver has failed.
The driver is electronic circuit on transistors, which controls the flashlight modes and is also responsible for a constant voltage level, regardless of battery discharge.
You need to unsolder the burnt driver and solder in a new driver, or connect the LED directly to the battery. In this case, you lose all modes and are left only with the maximum one.
Sometimes (much less often) the LED fails.
You can check this very simply. Apply a voltage of 4.2 V/ to the contact pads of the LED. The main thing is not to confuse the polarity. If the LED lights up brightly, then the driver has failed, if vice versa, then you need to order a new LED.
Unscrew the module with the LED from the housing.
Modules vary, but as a rule, they are made of copper or brass and are unscrewed counterclockwise. Unsolder the wires from the star with the LED and remove the driver.
Many people have various Chinese lanterns that run on a single battery. Something like this:
Unfortunately, they are very short-lived. I will tell you further about how to bring a flashlight back to life and about some simple modifications that can improve such flashlights.
The most weakness Similar flashlights have a button. Its contacts oxidize, as a result of which the flashlight begins to shine dimly, and then may stop turning on altogether.
The first sign is that a flashlight with a normal battery shines dimly, 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 and cut off one strand.
2. We wind the wires onto the spring.
3. We bend the wire so that the battery does not break it. The wire should protrude slightly
above the twisting part of the flashlight.
4. Twist tightly. We break off (tear off) the excess wire.
As a result, the wire provides good contact with the negative part of the battery and the flashlight
will shine with proper brightness. Of course, the button is no longer available for such repairs, so
Turning the flashlight on and off is done by turning the head part.
My Chinese guy 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 heads away.
RESTORING THE OPERATION OF THE BUTTON.
Today I decided to bring the button back to life. The button is located in a plastic case, which
It's just pressed into the back of the light. In principle, it can be pushed back, but I did it a little differently: 
1. Use a 2 mm drill to make a couple of holes to a depth of 2-3 mm.
2. Now you can use tweezers to unscrew the housing with the button.
3. Remove the button.
4. The button is assembled without glue or latches, so it can be easily disassembled with a stationery knife.
The photo shows that the moving contact has oxidized (a round thing in the center that looks like a button).
You can clean it with an eraser or fine sandpaper and put the button back together, but I decided to additionally tin both this part and the fixed contacts. 
1. Clean with fine sandpaper.
2. We serve thin layer places marked in red. We wipe off the flux with alcohol,
assembling the button.
3. To increase reliability, I soldered a spring to the bottom contact of the button.
4. Putting everything back together.
After repair, the button works perfectly. Of course, tin also oxidizes, but since tin is a fairly soft metal, I hope that the oxide film will be
easy to break down. It’s not for nothing that the central contact on light bulbs is made of tin.
IMPROVING FOCUS.
My Chinese friend had a very vague idea of what a “hotspot” was, so I decided to enlighten him.
Unscrew the head part. 
1. There is a small hole in the board (arrow). Use an awl to twist out the filling.
At the same time, lightly press your finger on the glass from the outside. This makes it easier to unscrew.
2. Remove the reflector.
3. Take ordinary office paper and punch 6-8 holes with an office hole punch.
The diameter of the holes in the hole punch matches perfectly with the diameter of the LED.
Cut out 6-8 paper washers.
4. Place the washers on the LED and press it with the reflector.
Here you will have to experiment with the number of washers. I improved the focusing of a couple of flashlights in this way; the number of washers was in the range of 4-6. The current patient required 6 of them.
What happened in the end: 
On the left is our Chinese, on the right is Fenix LD 10 (at minimum).
The result is quite pleasant. The hotspot became pronounced and uniform.
INCREASE THE BRIGHTNESS (for those who know a little about electronics).
The Chinese save on everything. A couple of extra details will increase the cost, so they don’t install it. 
The main part of the diagram (marked in green) may be different. On one or two transistors or on a specialized microcircuit (I have a circuit of two parts:
inductor and a 3-leg IC similar to a transistor). But they save money on the part marked in red. I added a capacitor and a pair of 1n4148 diodes in parallel (I didn't have any shots). The brightness of the LED increased by 10-15 percent.
1. This is what the LED looks like in similar Chinese ones. From the side you can see that there are thick and thin legs inside. The thin leg is a plus. You need to be guided by this sign, because the colors of the wires can be completely unpredictable.
2. This is what the board looks like with the LED soldered to it (on the back side). Green color indicates foil. The wires coming from the driver are soldered to the legs of the LED.
3. Using a sharp knife or a triangular file, cut the foil on the positive side of the LED.
We sand the entire board to remove the varnish.
4. Solder the diodes and capacitor. I took the diodes from a broken one computer unit power supply, the tantalum capacitor fell out of some burnt-out hard drive.
The positive wire now needs to be soldered to the pad with the diodes.
As a result, the flashlight produces (by eye) 10-12 lumens (see photo with hotspots),
judging by the Phoenix, which produces 9 lumens in minimum mode.
And the last thing: the advantage of the Chinese over the branded flashlight (yes, don’t laugh)
Branded flashlights are designed to use batteries, so
With the battery discharged to 1 volt, my Fenix LD 10 simply does not turn on. At all.
I took a dead alkaline battery that had expired in the computer mouse. The multimeter showed that it had dropped to 1.12v. The mouse no longer worked on it, Fenix, as I said, did not start. But the Chinese one works! 
On the left is the Chinese, on the right is the Fenix LD 10 at minimum (9 lumens). Unfortunately, the white balance is off.
The phoenix has a temperature of 4200K. The Chinese is blue, but not as bad as in the photo.
Just for fun, I tried to finish off the battery. At this brightness level (5-6 lumens by eye), the flashlight worked for about 3 hours. The brightness is quite enough to illuminate your feet in a dark entrance/forest/basement. Then for another 2 hours the brightness decreased to the “firefly” level. Agree, 3-4 hours with acceptable light can solve a lot.
For this, let me take my leave.
Stari4ok.
Z.Y. The article is not a copy-paste. Made in I, especially for “NOT PROPAD”!
The advantage of this lantern is that if it breaks, you don’t mind throwing it away. But not everything is thrown away :). A friend of mine brought it in for repairs. Something doesn't turn on, he says.
I have long been tormented by curiosity, how will a flashlight shine if you put an LED instead of a regular light bulb? And then such a case turned up! I did it for fun, but my friend liked it. I don’t care, he says, as long as it shines.
If you want to laugh, come in.
I bought LEDs back in 2014. At that time they were a little more expensive. At the moment the price is lower.
I made everything out of them: homemade light bulbs and inserted them into lamps. Now the flashlight is shining.
Let me remind you a little. The LEDs came in a standard package with a bubble wrap inside. Everything was packed according to upper class. I don't see any point in showing the unpacking.
All characteristics are written on the package. How we missed such toys in childhood! 
Exactly 100pcs.
There are no particular problems in disassembling such flashlights. Not everyone can put everything back together :). 
Inside is the usual ballast of capacitors and a pair of diodes as a rectifier. 
The problem for users is that they turn on the flashlight for charging in the “on” mode. The moment it is connected to the 220V network, the LED burns out. I redid the wiring of the switch/switch a little. Now until you switch it to the off state, it won’t charge. On some Chinese lanterns this idea has long been implemented, but not yet.
This is the LED I will change. This is, of course, not a light bulb, but you can find out how it will shine. 
There is no need to invent anything special to replace it.
This is what happened. 
I took pictures from different lighting angles. 
And this is how he shines in life. He climbed the stairs of the dark entrance. 
The characteristic spot cannot be removed anywhere. But if you feel like it, you can use it :)
That's all. I hope it helped at least someone.
Good luck everyone!
Hi all! Let's talk about LED flashlights. Who doesn't know them? They came to replace outdated battery-powered flashlights. They contained simple batteries and incandescent light bulbs, which quickly drained the flashlight's batteries and it ceased to please us with its bright light. Life does not stand still, and so does technology. Everything develops, something more perfect is invented. This has not spared LED flashlights either. What is this flashlight?
In principle, nothing much has changed, only instead of energy-intensive incandescent light bulbs they began to use economical, super-bright LEDs. In our market they appeared in Chinese illuminated lighters. Many people remember this. Well, then everything went on and on. The first LED flashlights were with dry batteries, then with rechargeable batteries from the mains. Then they began to produce street lighting lamps made up of several dozen super-bright LEDs.
Such flashlights shine with a peculiar light that corresponds to a certain spectrum. But other than that, I think they were not created to read books under their light. You will most likely ruin your eyes. The most important advantage of such flashlights is that they have less power consumption from the current source and a long service life. I think LED lamps have a great future. All that remains is to choose a spectrum that does not harm our vision.
Well, now let’s practically try to repair the LED flashlight. To begin with, I will give a simplified electrical diagram of a flashlight with a rechargeable battery from the mains.
As you can see, the scheme is simple. Main elements: current-limiting capacitor, rectifier diode bridge on four diodes, battery, switch, super-bright LEDs, LED to indicate 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 battery charging current. Its capacity for each type of flashlight may be different. A non-polar mica capacitor is used. The operating voltage must be at least 250 volts. In the circuit it must be bypassed, as shown, with a resistor. It serves to discharge the capacitor after you remove the flashlight from the charging outlet. Otherwise, you may get an electric shock if you accidentally touch the 220 volt power 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.
To indicate the charging of the flashlight battery, a simple red or green LED is used. It is connected in parallel to one of the diodes of the rectifier bridge. True, in the diagram I forgot to indicate the resistor connected in series with this LED.
It makes no sense to talk about the other elements; everything should be clear anyway.
I would like to draw your attention to the main points of repairing an LED flashlight. Let's look at the main faults and how to fix them.
1. The flashlight stopped shining. There aren't 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 jump in current will occur and one or more diodes of the rectifier bridge may be broken. And behind them, the capacitor may not be able to withstand it and will short out. The voltage on the battery will increase sharply and the LEDs will fail. So, under no circumstances turn on the flashlight while charging unless you want to throw it away.
2. The flashlight does not turn on. Well, here you need to check the switch.
3. The flashlight discharges very quickly. If your flashlight is “experienced”, then most likely the battery has reached its service life. If you actively use the flashlight, then after one year of use the battery will no longer last.
4. The flashlight is not charging. The charging indicator LED does not light up. Disassemble the flashlight and check the electrical wiring for breaks. If no break is found, then inspect the current-limiting capacitor. On appearance it may be swollen or intact. In any case, it must be replaced, as it may have an internal break. Install with such a capacity and an operating voltage of at least 250 volts. If the capacitor is damaged, check all diodes of the rectifier bridge
As you can see, the scheme is simple. Main elements: current-limiting capacitor, rectifier diode bridge with four diodes, battery, switch, super-bright LEDs, LED to indicate 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 battery charging current. Its capacity for each type of flashlight may be different. A non-polar mica capacitor is used. The operating voltage must be at least 250 volts. In the circuit it must be bypassed, as shown, with a resistor. It serves to discharge the capacitor after you remove the flashlight from the charging outlet. Otherwise, you may get an electric shock if you accidentally touch the 220 volt power 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.
To indicate the charging of the flashlight battery, a simple red or green LED is used. It is connected in parallel to one of the diodes of the rectifier bridge. True, in the diagram I forgot to indicate the resistor connected in series with this LED.
It makes no sense to talk about the other elements; everything should be clear anyway.
I would like to draw your attention to the main points of repairing an LED flashlight. Let's look at the main faults and how to fix them.
1. The flashlight stopped shining. There aren't 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 jump in current will occur and one or more diodes of the rectifier bridge may be broken. And behind them, the capacitor may not be able to withstand it and will short out. The voltage on the battery will increase sharply and the LEDs will fail. So, under no circumstances turn on the flashlight while charging unless you want to throw it away.
2. The flashlight does not turn on. Well, here you need to check the switch.
3. The flashlight discharges very quickly. If your flashlight is “experienced”, then most likely the battery has reached its service life. If you actively use the flashlight, then after one year of use the battery will no longer last.
Problem 1: The LED flashlight does not turn on or flickers when working
As a rule, this is the cause of poor contact. The easiest way to treat it is to tighten all the threads tightly.
If the flashlight doesn't work at all, start by checking the battery. It may be discharged or damaged.
Unscrew the back cover of the flashlight and use a screwdriver to connect the housing to the negative terminal 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 by a loose clamping ring.
To fix this problem, just find round pliers with thin tips or thin scissors that need to be inserted into the holes, as in the photo, and turned clockwise.
If the ring moves, the problem is fixed. If the ring stays in place, then the problem lies in the contact of the button module with the body. Unscrew the clamping ring counterclockwise and pull the button module out.
Poor contact often occurs due to oxidation of the aluminum surface of the ring or border on the printed circuit board (indicated by arrows)
Simply wipe these surfaces with alcohol and functionality will be restored.
Button modules are different. Some have contact through the printed circuit board, others have contact through the side petals to the flashlight body.
Just bend this petal to the side so that the contact is tighter.
Alternatively, you can make a solder from tin so that the surface is thicker and the contact is pressed better.
All LED lights are basically the same
The plus goes through the positive contact of the battery to the center of the LED module.
The negative goes through the body and is closed with a button.
It would be a good idea to check the tightness of the LED module inside the housing. 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 quite enough to restore the functionality of the LED flashlight.
It’s worse when the flashlight works and the modes are switched, but the beam is very dim, or the flashlight doesn’t work at all and there’s a burning smell inside.
Problem 2. The flashlight works fine, but is dim or does not work at all and there is a burning smell inside
Most likely the driver has failed.
The driver is an electronic circuit on transistors that controls the flashlight modes and is also responsible for a constant voltage level, regardless of battery discharge.
You need to unsolder the burnt driver and solder in a new driver, or connect the LED directly to the battery. In this case, you lose all modes and are left only with the maximum one.
Sometimes (much less often) the LED fails.
You can check this very simply. Apply a voltage of 4.2 V/ to the contact pads of the LED. The main thing is not to confuse the polarity. If the LED lights up brightly, then the driver has failed, if vice versa, then you need to order a new LED.
Unscrew the module with the LED from the housing.
Modules vary, but as a rule, they are made of copper or brass and
The weakest point of such flashlights is the button. Its contacts oxidize, as a result of which the flashlight begins to shine dimly, and then may stop turning on altogether.
The first sign is that a flashlight with a normal battery shines dimly, 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 and cut off one strand.
2. We wind the wires onto the spring.
3. We bend the wire so that the battery does not break it. The wire should protrude slightly
above the twisting part of the flashlight.
4. Twist tightly. We break off (tear off) the excess wire.
As a result, the wire provides good contact with the negative part of the battery and the flashlight
will shine with proper brightness. Of course, the button is no longer available for such repairs, so
Turning on and off the flashlight is done by turning the head part.
My Chinese guy 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 heads away.
RESTORING THE OPERATION OF THE BUTTON.
Today I decided to bring the button back to life. The button is located in a plastic case, which
It's just pressed into the back of the light. In principle, it can be pushed back, but I did it a little differently:
1. Use a 2 mm drill to make a couple of holes to a depth of 2-3 mm.
2. Now you can use tweezers to unscrew the housing with the button.
3. Remove the button.
4. The button is assembled without glue or latches, so it can be easily disassembled with a stationery knife.
The photo shows that the moving contact has oxidized (a round thing in the center that looks like a button).
You can clean it with an eraser or fine sandpaper and put the button back together, but I decided to additionally tin both this part and the fixed contacts.
1. Clean with fine sandpaper.
2. Apply a thin layer to the areas marked in red. We wipe off the flux with alcohol,
assembling the button.
3. To increase reliability, I soldered a spring to the bottom contact of the button.
4. Putting everything back together.
After repair, the button works perfectly. Of course, tin also oxidizes, but since tin is a fairly soft metal, I hope that the oxide film will be
easy to break down. It’s not for nothing that the central contact on light bulbs is made of tin.
IMPROVING FOCUS.
My Chinese friend had a very vague idea of what a “hotspot” was, so I decided to enlighten him.
Unscrew the head part.
1. There is a small hole in the board (arrow). Use an awl to twist out the filling.
At the same time, lightly press your finger on the glass from the outside. This makes it easier to unscrew.
2. Remove the reflector.
3. Take ordinary office paper and punch 6-8 holes with an office hole punch.
The diameter of the holes in the hole punch matches perfectly with the diameter of the LED.
Cut out 6-8 paper washers.
4. Place the washers on the LED and press it with the reflector.
Here you will have to experiment with the number of washers. I improved the focusing of a couple of flashlights in this way; the number of washers was in the range of 4-6. The current patient required 6 of them.
INCREASE THE BRIGHTNESS (for those who know a little about electronics).
The Chinese save on everything. A couple of extra details will increase the cost, so they don’t install it.
The main part of the diagram (marked in green) may be different. On one or two transistors or on a specialized microcircuit (I have a circuit of two parts:
inductor and a 3-leg IC similar to a transistor). But they save on the part marked in red. I added a capacitor and a pair of 1n4148 diodes in parallel (I didn't have any shots). The brightness of the LED increased by 10-15 percent.
1. This is what the LED looks like in similar Chinese ones. From the side you can see that there are thick and thin legs inside. The thin leg is a plus. You need to be guided by this sign, because the colors of the wires can be completely unpredictable.
2. This is what the board looks like with the LED soldered to it (on the back side). Green color indicates foil. The wires coming from the driver are soldered to the legs of the LED.
3. Using a sharp knife or a triangular file, cut the foil on the positive side of the LED.
We sand the entire board to remove the varnish.
4. Solder the diodes and capacitor. I took the diodes from a broken computer power supply, and soldered the tantalum capacitor from some burnt-out hard drive.
The positive wire now needs to be soldered to the pad with the diodes.
As a result, the flashlight produces (by eye) 10-12 lumens (see photo with hotspots),
judging by the Phoenix, which produces 9 lumens in minimum mode.
