In detail: do-it-yourself repair of a Chinese LED flashlight from a real master for the site my.housecope.com.
Hey! Today we'll see how to repair a Chinese LED flashlight at home with our own hands. We will spend at the same time a minimum of family budget funds. Did you know that the first electric flashlight was not Chinese at all. It was invented in 1896 by the American David Meisell. He patented an electric torch, the body of which was made of wood with a carrying handle. By this time, a zinc battery and an incandescent lamp had already been invented, so the flashlight was a matter of time. Popular today chinese led flashlight PM-0107 can be bought for just a couple of hundred rubles. This will already be a flashlight with built-in 220 volt charging. Today we'll see how to fix the frequent breakdowns of such a Chinese flashlight at home with our own hands. The background from Master Sergei is as follows: the owner of the flashlight turned it on for charging and accidentally touched the switch of the flashlight.
The flashlight flashed and went out... At the same time, we managed to break off part of the plug to charge it from the mains. Well, let's see how to fix such a miracle of the Chinese industry. It is very easy to disassemble such a flashlight - you need to unscrew three self-tapping screws and move the two halves of the plastic body of the flashlight apart.
Inside we see a rechargeable battery, a board with seven LEDs and a reflector. There is a switch for the operating mode of the flashlight and a battery charging board with a connected plug for a 220 volt network. To make it easier to repair our simplest Chinese flashlight, we disassemble it thoroughly, pulling out all the elements on the table.
Particular attention should be paid to the battery charging board from the mains - check the status of the rectifier diodes, indicator green LED and high-voltage capacitor. It does not hurt to check the operation of the flashlight mode switch button.
We thoroughly check the LEDs on the round board.
- it seems that when the power is thrown, they shorted. We change them to those of suitable size and luminosity from old stocks or bought in a store.
We solder the wires in place and check the LED power supply circuit assembly.
Repairing a broken charging plug from the network for our flashlight can be done in several ways - for example, you can buy a plug separately and adapt it in place, or carefully drill the plug of the plug with plastic and insert a paper clip there, putting the whole thing on glue or pouring it in with epoxy resin.
We assemble our Chinese device in the reverse order. Now we are glad that we spent repairing chinese flashlight do it yourself. If the flashlight could not be repaired, then you can think about purchasing a new simple or sophisticated flashlight.
Video (click to play).
Master of Soldering and Master Sergei tried for you.
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 the scarf, 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.
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. What happened in the end: On the left is our Chinese, on the right is Fenix LD 10 (at the minimum). The result is quite pleasant. The hot spot has become pronounced and even.
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. We solder the diodes and the 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.
And the last: the advantage of the Chinese over the branded flashlight (yes, don't laugh)