DIY dvd power supply. Replacing the DVD power supply. So, we will consider the repair of a DVD player using a specific example.

Hello everyone!

In this article I will show you how you can make dvd power supply repair , or rather to produce replacement of the power supply from another similar dvd player .

So, repair dvd player we will consider using a specific example.

A dvd player made in China was received for repair.

This unit did not turn on at all. According to the client, the device was turned off with the STOP button and left in this state for a long time (several hours). The next time the player was turned on, it simply did not turn on and there was no indication.

With this symptom, the first thing that can be suspected is dvd power supply ... Naturally, to find out the cause of the breakdown and make repair dvd player , you need to disassemble it, which was done.

After disassembly and visual inspection, a burnt-out microcircuit was found in power supply dvd - from it, most likely from overheating, a part of the case broke off. Due to the chip, it was impossible to read the inscription on this part, but it is known from experience that VIPer 22A or similar microcircuits are installed in such power supplies. To "cure" this power supply unit (PSU), you can simply replace the microcircuit, especially since they are quite inexpensive. But in this case I decided to use another option, namely to produce replacement of the power supply from another dvd player... I didn’t have a working DVD, in which the laser head was out of order. Because repair given dvd was not profitable due to the cost of the laser, but the power supply unit in it was serviceable, so it was decided to use it. In the photo below I present to you this power supply:

In most dvd players, especially those made in China, the output voltages in the PSU are the same (+ 5V, + 12V, -12V and GND) and differ only in the location of the contacts.

As you can see in the photo above, the voltages on both power supplies are the same, but there are some discrepancies in the location of the contacts.

This is fixable - you need to swap the contacts on the cable that connects to this connector. In our case, we only need to change the location of one contact. The photo below shows everything:

The first photo shows the initial arrangement of the contacts on the cable, the second shows the process of removing the desired contact of the cable from the connector (I took a small screwdriver, bent the metal plate that was the contact stopper). Photo # 3 shows how easily the contact is removed from the connector, after bending the plate - the stopper. Well, the fourth photo shows how the contact we need is inserted into the right place.

After carrying out all the above steps, the dvd power supply was fixed in the player's case.

Now you can make a test turn on of our DVD player.

The heyday of optical media such as CDs and DVDs turned out to be bright, but short-lived. Today, DVD players, after wear or damage, are no longer repaired, but discarded or discarded. best case disassembled into details. Inexpensive DVD-players usually contain a 6 ... 20 W switching power supply in the form of a separate module, which, after a little modification, can be successfully used to power other devices.

One of the units of the VVK DV31851 DVD-player is its SKY-P00807 power supply unit. which is suitable for reuse... It has three output channels (+5 V, + 12V -12 V) with a total power of about 14 W. On the basis of this block shown on the site, it was possible to make Charger for various mobile multimedia devices. According to the author, it has a significant the best parameters, including reliability than the numerous Cell Phones, tablet computers, e-books. Mp3 players, navigators and other modern "toys".

The first stage in the modification of the SKY-P00807 unit was the installation of a noise suppression filter at its mains input, assembled according to the diagram shown in Fig. 1. The fusible link F601 was moved from the printed circuit board of the unit to the holder installed on the device body. The SA1 power switch, which had been missing earlier, was also installed on the body. The rest of the filter elements were placed on the printed circuit board of the block.

Now the mains voltage is 230 V through the closed contacts of the switch and the fuse, as well as through the resistors R1 and R2 reducing the inrush current, to the LC filter C1L1C2. After the filter, it goes to the network input of the unit. Varistor RU1 protects the device from overvoltage in the supply network.

The installation of limiting resistors made it possible to replace the fuse-link for a current of 1 A with a similar one for 0.25 A. These resistors also reduced the likelihood of damage to the power supply by impulse network noise. For the same purpose, a high-voltage ceramic capacitor was removed from the unit, which connected the common wires of the primary and secondary circuits of the voltage converter. A two-winding choke L1 is of industrial production, any similar small-sized choke with a winding inductance of at least 1 mH and a total resistance of no more than 40 ohms is suitable. The greater the inductance. all the better.

In the process of revision, a swollen oxide smoothing capacitor of the +5 V voltage rectifier was found in the unit. This 470 μF capacitor was replaced with a 1500 μF oxide capacitor. in parallel to which a ceramic capacitor with a capacity of 10 μF was soldered. To increase the output voltage from +5 V to 5.6 V in parallel with a 10 kΩ resistor. connected between terminals 1 and 2 of the TL431 parallel voltage regulator available in the microcircuit block, a 43 kOhm resistor was connected.

Integrated microcircuit The TNY275PN switching voltage converter previously worked with a heat sink only in the form of a foil patch on the board. To facilitate the temperature regime of this microcircuit, an additional heat sink was soldered to its heat sink pins 5-8 - a copper plate with a cooling surface area of 3 cm.

Capacitor C601 (Fig. 1) was replaced by a capacitor of the same capacity, but for an operating voltage of 450 V instead of 400 V. This was done in order to move it away from the heating TNY275PN microcircuit due to the long terminals of the new capacitor.

During experiments with the power supply, it was found that in the case of connecting the load only to the +5 V output (+5.6 V after revision), the voltage between the plates of smoothing capacitors of the rectifiers of the output voltages of +12 V and -12 V exceeded 20 V. Since the aforementioned outputs of the modified unit are not used, the diodes of these rectifiers are designated on its board as D610 and D611. were dismantled.

If high-frequency rectifier diodes are found to be faulty in the power supply being modified, then they can be replaced with diodes from the KD247, UF400x series corresponding to the permissible reverse voltage.They can also be replaced with diodes 1 N4007. The defective EL817 optocoupler is replaced with any four-pin with the numbers 817 in the name, for example. LTV817 or PC817. Instead of a TL431 chip, an AZ431 or LM431 in a TO-92 package is suitable.

Filter capacitors C1 and C2 are film or ceramic, capable of operating at an alternating voltage of 50 Hz of at least 250 V. Their capacity can be in the range of 4700 ... 10000 pF Oxide capacitors additionally installed in the unit - K53-19. K53-30 or imported analogs of capacitors K50-35 and K50-68. Disk varistor RU1 - TVR10471, which can be replaced by MYG14-471, MYG20-471, FNR-14K471, FNR-20K471 or GNR20D471K. Give preference to a varistor in a housing with a larger diameter.

The +6.6 V voltage from the power supply output was applied to an additionally manufactured module, the diagram of which is shown in Fig. 2 Three loads with a total current consumption of up to 2 A can be simultaneously connected to its connectors XP1, XS1 and XS2. The output voltage is about +6 V. When the load is connected to the XS1 socket, the germanium transistor VT1 opens with a voltage drop across the resistor R3 and turns on the HL2 LED. With room lighting, its glow becomes noticeable already at a load current of 10 mA. The node on the VT2 transistor and the HL3 LED works in a similar way when the load is connected to the XS2 socket. Schottky diodes VD3 and VD6 limit the voltage drop across resistors R3 and R8 with increasing load current, thereby protecting the emitter junctions of transistors VT1 and VT2.

The XP1 connector is a splitter. equipped with plugs of different types. When a load is connected to it, the HL2 and HL3 LEDs will light up simultaneously. Some mobile devices "forget" to close the corresponding electronic key... As a result, the battery voltage is supplied to the socket of their external power supply, which can lead to the fact that one mobile device a discharged battery will consume the energy of another charged battery. To prevent this situation, the power supply outputs are decoupled by VD2 Schottky diodes. VD4, VD5, VD7.

Limiting diode (suppressor) VD1 protects the loads connected to the connectors from damage increased voltage if the power supply fails. The HL1 LED shines when the device is connected to the network. Filter C1L1L2C3C4 reduces the level of ripple of the output voltage of the switching power supply. Their swing at connectors XP1, XS1 and XS2 does not exceed 10 mV at a load current of 2 A. This is significantly less than that of various ones, where ripple can reach hundreds of millivolts.

Details of the device according to the diagram in Fig. 2 are mounted on a 75 × 25 mm mounting plate. Installation - double-sided hinged. Resistors R5 and R10 are soldered directly to the contacts of the XS1 and XS2 sockets. LEDs HL2 and HL3 are installed near these sockets. Chokes L1, L2 - industrial production on H-shaped magnetic circuits, the greater their inductance and the lower the resistance of the windings, the better. Germanium transistors SFT352 can be replaced with domestic ones from the MP25, MP26, MP39-MP42 series. The diodes included in the MBRD620CT assemblies are connected in parallel to improve reliability, reduce heat build-up and reduce voltage drop. When selecting diodes to replace them, give preference to powerful low-voltage Schottky diodes. Suitable, for example. MBRD630CT. MBRF835. MBRD320. MBRD330, 1N5820, 1N5821. Limiting diodes P6KE6.8A can be replaced with 1N5342 zener diodes. LEDs can be of any type general use continuous glow, for example, series KIPD40, L-1053, L-173.

The device is assembled in a plastic case measuring 172x72x37 mm. The location of its nodes inside the body is shown in Fig. 3. Weight of the structure - 240 g without power cords The manufactured power supply at a voltage of 230 V consumes from it a current of 1.5 mA in idle mode and about 26 mA at a load current of 1 A. A pleasant surprise was that. that even without shielding the switching power supply, the described device does not have a noticeable negative effect on the reception quality of broadcast radio stations of all ranges, even if the radio receiver is nearby. After all, ordinary telephone chargers with their interference often completely jam the radio reception, even on the VHF bands.

In addition to various digital mobile multimedia devices, this power source can be used to connect "four-battery" cameras and video cameras designed for 4.8 ... 6.4 V voltage, radios, and children's toys. Similarly, you can modify and use other pulse blocks nutrition. dismantled from faulty or unnecessary household electronic devices, for example, unit GL001A1. In some cases, retrofitting can be simplified, since many units already have a two-winding choke at the mains input.

In any electronic device impulse power supplies (UPS) occupy one of the leading places in terms of the number of failures. DVD-players are no exception, where UPS malfunctions are not much less common than laser heads contamination. The UPS circuit described in the article is used in at least ten models of Samsung Electronics Co. DVD-players, such as: DVD-511, DVD-611, DVD-611B, DVD-615, DVD-711, DVD-718, DVD-811, DVD-812, DVD-818, DVD-818J, DVD-819, etc.

In the above models of DVD-players, produced for Europe and the CIS countries, a flyback switching power supply with PWM is used, which is designed to operate from an alternating current 50/60 Hz with a voltage of 85 ... 265 V without additional switching (Free Voltage). The power consumption of the electrical current of the UPS from the mains is 17.18 W. A simplified functional diagram of this block is shown in Fig. 1.

Rice. 1. Simplified functional diagram of the UPS for DVD-players

Rice. 2. Functional diagram of the STR-G6551 PWM controller microcircuit

The alternating mains voltage is fed through the noise suppression filter to the bridge rectifier. The rectified voltage is smoothed by a filter and through the primary winding of the pulse transformer goes to the drain of the field-effect transistor - the output switch of the PICF1 PWM controller (STR-G6551). A damper is used to protect the output switch transistor from breakdown by self-induction EMF pulses. For group stabilization of the UPS output voltages, the STR-G6551 PWM controller receives an error voltage from the control circuit, which is formed from a secondary voltage of + 5.8 V.

Description of some elements of the UPS

The basis of this power supply is a PICF1 PWM controller of the STR-G6551 type.

Table 1. Purpose of the pins of the STR-G6551 microcircuit

Its functional diagram is shown in Fig. 2, and the purpose of the conclusions is in table. 1.

STR-G6551 microcircuit contains:

start-up scheme (START);

internal voltage regulator;

thermal and overvoltage protection circuits;

OR element and flip-flop "latch" of the protection circuit;

pulse generator;

pre-output stage (driver);

an output switch based on a high-voltage MOS transistor with a damping diode;

PWM comparator and overcurrent protection circuit (Comp);

OR element of the PWM control circuit.

In the chain feedback The UPS uses a type 431 PICS2 microcircuit (according to the specification, the SAMSUNG KA431Z microcircuit is used). This IC is often referred to as a "regulated (programmable) zener diode" or Programmable shunt voltage reference. A simplified functional diagram of the microcircuit is shown in Fig. 3.

Rice. 3. Simplified functional diagram of the adjustable zener diode KA431Z

Such a discrete circuit is commonly referred to as a comparison circuit or an "error amplifier". Fig. Figure 3 shows that the KA431Z contains a 2.5 V reference, a comparator, and an open collector control transistor. A reference voltage of 2.5 V is supplied to the comparator inputs and through an external divider - a part of one of the secondary positive voltages of the UPS (at pin. R). The comparator compares these voltages and through the transistor, and the regulating unit of the UPS controls the output voltages of both the switching and linear power supply. The location and purpose of the pins of the KA431Z microcircuit in the TO92 package is shown in Fig. 4.

Rice. 4. Location and purpose of the terminals (TO-92 case)

The UPS also uses an opto-pair PICS1 (PC123), an uncontrolled -8 V stabilizer PICS3, type 7908, and controlled stabilizers +8 V PICS4, type 78R08 and +3.3 V PICS5, type PQ3RF23. The so-called digital transistors (KSR1101 and KSR1103 - n-p-n structures, KSR2101 - p-n-p structures), each of which, except, in fact, the transistor itself, contains a resistive divider of the base bias.

Schematic diagram UPS

The schematic diagram of the UPS is shown in Fig. 5.

Rice. 5. Schematic diagram of the UPS

Note. The diagram in this figure uses somewhat unusual designations for the position numbers of parts.

They all begin with the Latin letter P (abbreviation for Power), which indicates that the part belongs to the power supply.

There are three or four letters in the reference designation of the part. The second letter of three or the second and third of four show the type of part: D - diode, Q - transistor, R - resistor, C - capacitor, E - oxide (electrolytic) capacitor, F - fuse, L - inductance (choke), B - inductance (choke) in the form of a ferrite tube, put on a jumper or part output (CORE-FERRITE BEAD), T - transformer, V - varistor, Z - zener diode, IC - microcircuit, CN - connector.

The last third or fourth letter indicates the belonging of the part to a particular chain. So, the letter F denotes the parts of the primary circuits, and the letter S - the parts of the secondary circuits, etc. The positional number of any part (except for PVA1 varistor and PTD1 pulse transformer) contains five characters. So, a positional part number with four letters ends with one digit, and with three letters ends with two digits. For example: PICS3 or PEF12. Consider the operation of the UPS according to the diagram in Fig. 5. The mains rectifier with the noise protection circuit is quite simple and does not require any special explanations. It is assembled on PDS01-PDS04 diodes. Varistor PVA1 protects the UPS and the entire device from overload in the event of a significant increase in the mains voltage. The voltage of 290 ... 310 V obtained with the help of a network rectifier (for an AC 220 V network) is smoothed by a PEF10 capacitor and is used to power the UPS converter. The PRF10 resistor limits the charging current of the PEF10 capacitor, thereby protecting the rectifier bridge diodes from overload when turned on. When the DVD player is connected to the network, the PEF12 trigger circuit capacitor is charged from the network through the noise suppression filters, the PDF01 diode and the PRF11, PRF12, PRF13, PRF14 trigger circuit resistors. When the voltage across this capacitor and on the pin. 4 microcircuits reaches 16 V, the starting circuit is turned on and the voltage from the PEF12 capacitor through this circuit is supplied to power the main nodes of the STR-G6551 microcircuit. In this case, the first positive pulse is sent to the gate of the MIS transistor of the microcircuit, which opens this transistor. Since the transistor is loaded on the primary winding (1-3) of the pulse transformer PTD1, the resistance of which is inductive, the drain current of this transistor will be increasing. Flowing through the PRF20 resistor (current sensor), the current creates an increasing (sawtooth) voltage drop across it, which is applied to the pin through PRF19. 5 of the STR-G6551 chip, where it is added to the constant voltages supplied there through the PRF15 and the PICS1 optocoupler. When the current of the MOS transistor of the microcircuit increases so much that the voltage at the pin. 5 will exceed a certain limit (1.45 V), the comparator of the microcircuit will issue a command to turn off this transistor, and it will close before the next pulse arrives. The blocking moment of the MOS transistor depends both on its drain current and on the degree of opening of the phototransistor of the PICS1 optocoupler. The duration and duty cycle of the pulses in the PTD1 transformer also depend on this.

Pulses with pin. 4 transformers PTD1 through a PDF13 diode and a PRF16 resistor recharge the PEF12 storage capacitor, providing necessary nutrition microcircuit and phototransistor of optocoupler PICS1 PC123 in steady state (working or standby).

If the circuit is faulty or overloaded, then the pulses on the pin. 4 PTD1 missing or insufficient swing to recharge capacitor PEF12. The capacitor will be discharged and will be charged again, and the circuit will go into cyclic operation.

To protect the output MOS transistor of the microcircuit from overvoltage, the swing of the reverse pulses on the primary winding of the PTD1 transformer is limited by the PCF11 PFD12 PBD11 PDS11 PRS11 PRS12 circuit.

Now let's look at how the group stabilization of the UPS output voltages is carried out. Suppose these tensions are growing. The voltage at the input of the PICS2 stabilization stage will also increase, its output current, and therefore the current through the IR diode of the optocoupler, will increase, which will lead to a decrease in the resistance of the optocoupler phototransistor and a decrease in the constant voltage at the pin. 5 chips STR-G6551. At the same time, to block the output transistor of the microcircuit, a slightly larger value of the sawtooth voltage from the PRF20 current sensor will be needed, which means that the MIS transistor will be open longer. This will lead to a decrease in the duty cycle of the pulses at the output of the microcircuit and in the pulse transformer, and to a decrease in the output voltages of the UPS to the previous value. Similarly, but with an accuracy "on the contrary", the process takes place in the case of a decrease in the output voltages at the output of the converter.

The purpose and features of the elements of secondary UPS sources are given in table. 2.

Table 2. Secondary UPS power supplies

Rectifiers	Stabilizers	Appointment	Application
PDS31	PICS1 (7908)	Source -8 V	Power supply for AUDIO and VIDEO units
PDS32	-	+ 10 ... + 12 V source	Auxiliary source for obtaining commuting stresses
PDS32	PICS4 (78R08)	+8 V source	Power supply for AUDIO and VIDEO units
PDS33	-	+ 5.8V source	Used to power the cascade stabilization, IR diode optocoupler (in the chain of stabilizing OOS) and to get all the weekend voltage 5 V
	On the PQS57 transistor	+5 V source	Power supply of the analogue part of AUDIO, VIDEO and other sites
	On the PQS58 transistor	+5 V source	Power supply for the digital part of AUDIO, VIDEO and other sites
	No additional stabilization	+5 V source	Power supply of the main units of the apparatus (via isolation diode PDS52 and integral fuse PIC56 N20)
PDS34	PICS5 (PQ3RF23)	+3.3 V source	Power supply of the digital part controllers
PDD35	-	-28 V source	Fluorescent power indicator
PDS36	-	Fluorescent filament voltage source indicator

Let's consider some additional features of the UPS circuit.

To obtain a stabilized voltage of +8 V, a PICS4 (78R08) microcircuit is used, which has a PWR CTL control input (pin 4). This pin is connected through a PRS56 resistor to the cathode of the PDS52 diode (+5 V source). This is done so that in the absence of + 5 V voltage, the + 8 V voltage is also turned off.

Another feature of the scheme is the availability external signal SAVE. This signal directly controls the switch on the PQL57 transistor. In standby or operating modes, the transistor is open at the log level. "1", which leads to the opening of the associated keys for controlling the output voltages on the PQL58 (+ 8 V per AUDIO node), PQL56, PQL55 (-8 V per AUDIO node), PQL51, PQL52 (fluorescent indicator glow voltage) and PQL53 transistors , PQL54 (supply voltage of the fluorescent indicator). If the SAVE signal is low (log. "0"), then the PQL57 transistor and all the switches associated with it will close. This will disconnect the listed voltages.

And finally, the last feature. The standby mode of the UPS differs from the operating mode by the absence of voltage +3.3 V and two voltages + 5 V for powering the analog and digital parts of the entire device. The transfer of the device from one mode to another is carried out by the ON / OFF signal (log. "1" - on, log. "0" - off). This signal to control the supply of voltage +3.3 V is fed to the PWR CTL control input (pin 4) of the PICS5 microcircuit (PQ3RF23). + 5 V voltage regulators are controlled using switches on digital transistors PQS56 and PQS55. Log level. "1" in the operating mode opens the PQS56 transistor, which ensures the opening of the PQS55 transistor. Through this transistor, voltage is supplied to the parametric stabilizer on the PZS51 zener diode and the PDS51 diode, connected to the base circuits of the PQS57 and PQS58 transistors, providing two +5 V voltages at the emitters of these transistors.

The device does not turn on. Mains fuse blown

If the mains fuse is blown, do not replace it and immediately plug the device into the mains. Check the protective varistor for an open, and the bridge diodes and the output transistor of the PWM controller microcircuit for a short circuit. A break in the varistor indicates that there was an overload on the supply voltage. The capacitor of the smoothing filter PEF10 and the capacitors of the noise suppression filter break through somewhat less often. It should be remembered that this defect can burn out the PRF20 current sensor and the PRF10 limiting resistor.

The output transistor of the STR-G6551 chip usually fails for the following reasons:

The network voltage is too high;

The optocoupler PICS1 is faulty;

Defective stabilization stage PICS2.

The device does not turn on. Mains fuse intact

The power supply may not start for the following main reasons:

No voltage of +300 V on the capacitor of the smoothing filter PEF10;

The PRF20 current sensor is interrupted;

The parts of the starting circuit are cut off: diode PDF01 or PRF11, PRF12, PRF13, PRF14;

Loss of capacity or leakage of PEF12 capacitor;

Short circuit in the circuits of secondary power supplies;

Malfunction of the controller PWM microcircuit.

The device spontaneously switches from operating mode to standby

A similar effect can occur due to short circuits in the secondary circuits of the power supply, at the command of the control processor, or when the capacitance of PEF12 decreases.

Defects appear in the device due to the absence of certain voltages at the UPS output

In the absence of one or more output voltages of the power supply, the switching keys, stabilizers and rectifiers should be checked. All these chains are discussed in sufficient detail in the article.

The heyday of optical media such as CDs and DVDs turned out to be bright, but short-lived. Today, DVD players are no longer repaired after wear or damage, but are thrown away or, at best, disassembled into parts. Inexpensive DVD-players usually contain a 6 ... 20 W switching power supply in the form of a separate module, which, after a little modification, can be successfully used to power other devices.

One of the parts of the BBK DV31851 DVD player is its SKY-P00807 power supply, which is recyclable. It has three output channels (+5 V, + 12V, -12 V) with a total power of about 14 W. On the basis of this unit, it was possible to manufacture a charger and power supply for various mobile multimedia devices. According to the author, it has significantly better parameters, including reliability, than numerous small-sized chargers that are used in cell phones, tablet computers, electronic books, MP-3-players, navigators and other modern "toys".

The first stage in the refinement of the SKY-P00807 unit was the installation of a noise suppression filter at its network input, assembled according to the diagram shown in Fig. 1. Fuse F601 has been moved from the PCB of the block to the holder installed on the device body. The SA1 power switch, which was absent earlier, was also installed there on the case. The rest of the filter elements were placed on the printed circuit board of the block.

Rice. 1. Noise suppression filter circuit

Now the mains voltage ~ 230 V is supplied to the LC filter C1L1C2 through the closed contacts of the switch and the fuse-link, as well as through the resistors R1 and R2 reducing the inrush current. After the filter, it goes to the network input of the unit. Varistor RU1 protects the device from overvoltage in the supply network.

Two-winding choke L1 is of industrial production, any similar small-sized choke with winding inductance of at least 1 mH and their total resistance of no more than 40 ohms is suitable. The larger the inductance, the better.

In the process of revision, a swollen oxide smoothing capacitor of the +5 V voltage rectifier was found in the block.This capacitor with a capacity of 470 μF was replaced with an oxide capacitor with a capacity of 1500 μF, in parallel to which a ceramic capacitor with a capacity of 10 μF was soldered. To increase the output voltage from +5 V to +5.6 V, a 43 kΩ resistor was connected in parallel with a 10 kΩ resistor connected between pins 1 and 2 of the TL431 parallel voltage stabilizer in the microcircuit unit.

The TNY275PN integrated circuit of a pulse voltage converter previously worked with a heat sink only in the form of a foil section on the board. To facilitate the temperature regime of this microcircuit, an additional heat sink was soldered to its heat sink pins 5-8 - a copper plate with a cooling surface area of 3 cm 2.

During experiments with the power supply, it was found that in the case of connecting the load only to the +5 V output (+5.6 V after revision), the voltage between the plates of the smoothing capacitors of the rectifiers of the output voltages +12 V and -12 V exceeded 20 V. of the modified unit are not used, the diodes of these rectifiers, designated on its board as D610 and D611, were dismantled.

If the high-frequency rectifier diodes are faulty in the power supply being modified, then they can be replaced with diodes from the KD247, UF400x series corresponding to the permissible reverse voltage. They can also replace diodes 1 N4007. The defective EL817 optocoupler is replaced with any four-pin with 817 in the name, for example, LTV817 or PC817. Instead of a TL431 chip, an AZ431 or LM431 in a TO-92 package is suitable.

Filter capacitors C1 and C2 are film or ceramic, capable of operating at an alternating voltage of 50 Hz at least 250 V. Their capacitance can be in the range of 4700 ... 10000 pF. Additionally installed in the unit oxide capacitors - K53-19, K53-30 or imported analogs of capacitors K50-35 and K50-68. Disk Varistor RU1 - TVR10471, which can be replaced by MYG14-471, MYG20-471, FNR-14K471, FNR-20K471 or GNR20D471K. Give preference to a varistor in a housing with a larger diameter.

The +5.6 V voltage from the power supply output was applied to an additionally manufactured module, the diagram of which is shown in Fig. 2. Its XP1, XS1 and XS2 connectors can simultaneously connect three loads with a total current consumption of up to 2 A. Output voltage is about +5 V.

Rice. 2. Scheme of an additionally manufactured module

When the load is connected to the XS1 socket, the germanium transistor VT1 opens with a voltage drop across the resistor R3 and turns on the HL2 LED. With room lighting, its glow becomes noticeable already at a load current of 10 mA. The node on the VT2 transistor and the HL3 LED works in a similar way when the load is connected to the XS2 socket. Schottky diodes VD3 and VD6 limit the voltage drop across resistors R3 and R8 with increasing load current, thereby protecting the emitter junctions of transistors VT1 and VT2.

Connector XP1 is a splitter equipped with plugs different types... When a load is connected to it, the HL2 and HL3 LEDs will light up simultaneously.

Some mobile devices "forget" to close the corresponding electronic key after the end of charging the accumulators built into them. As a result, the battery voltage is supplied to their external power socket, which can lead to the fact that one mobile device with a discharged battery will consume the energy of the charged battery of another. To prevent this situation, the power supply outputs are isolated by Schottky diodes VD2, VD4, VD5, VD7.

The limiting diode (suppressor) VD1 protects the loads connected to the connectors from damage by overvoltage in the event of a power supply failure. The HL1 LED shines when the device is connected to the network. Filter C1L1L2C3C4 reduces the level of ripple of the output voltage of the switching power supply. Their swing at connectors XP1, XS1 and XS2 does not exceed 10 mV at a load current of 2 A. This is significantly less than that of various telephone chargers, where ripple can reach hundreds of millivolts.

Details of the device according to the diagram in Fig. 2 are mounted on a 75x25 mm mounting plate. Installation - double-sided hinged. Resistors R5 and R10 are soldered directly to the contacts of the XS1 and XS2 sockets. LEDs HL2 and HL3 are installed near these sockets.

Chokes L1, L2 - industrial production on H-shaped magnetic wires, the greater their inductance and the lower the resistance of the windings, the better. Germanium transistors SFT352 can be replaced with domestic ones from the MP25, MP26, MP39-MP42 series. The diodes included in the MBRD620CT assemblies are connected in parallel to improve reliability, reduce heat build-up and reduce voltage drop. When selecting diodes to replace them, give preference to powerful low-voltage Schottky diodes. Suitable, for example, MBRD630CT, MBRF835, MBRD320, MBRD330, 1N5820, 1N5821. The limiting diodes P6KE6.8A can be replaced with 1N5342 zener diodes. LEDs can be of any type of general application of continuous luminescence, for example, series KIPD40, L-1053, L-173.

The device is assembled in a plastic case measuring 172x72x37 mm. The location of its nodes inside the body is shown in Fig. 3. Weight of the structure - 240 g without power cords. The manufactured power supply at a voltage of 230 V consumes from it a current of 1.5 mA in idle mode and about 26 mA at a load current of 1 A.

Rice. 3. The location of the device components inside the case

It was a pleasant surprise that even without shielding the switching power supply, the described device does not have a noticeable negative effect on the reception quality of broadcast radio stations of all ranges, even if the radio receiver is nearby. After all, ordinary telephone chargers with their interference often completely jam the radio reception, even on the VHF bands.

In addition to various digital mobile multimedia devices, this power source can be used to connect "four-battery" cameras and camcorders designed for 4.8 ... 6.4 V voltage, radios, and children's toys. In a similar way, you can modify and use other switching power supplies dismantled from faulty or unnecessary household electronic devices, for example, the GL001A1 unit. In some cases, the modification can be simplified, since many units already have a two-winding choke at the mains input.

It often happens that the light in the house was turned off, it was necessary to urgently call somewhere, and the phone charge was at zero. Or the phone runs out of power during the trip and there is nowhere to charge it. Make a charger for any phone from DVD drive Is the ideal solution in such situations. In addition, this is done quite simply and does not require large costs.

In our video you can see step by step instructions in creating such a charger.

To work we need:
- DVD drive;
- screwdriver;
- a small file or a hacksaw;
- glue gun;
- metal cover
- helium pen case;
- candle;
- USB female socket.

First of all, unscrew the bottom panel of the DVD drive with a screwdriver. To open the tray, you need to insert a needle into the corresponding hole and open it. Now we remove the front panel, which covers the driving part of the drive.

Separate the bottom case cover. We unscrew the screws securing the slide and the engine, remove the tray. Disconnect all connected cables from the connectors. We completely remove the sled with all its components.

For work, we leave only the motor and gear unit.

Saw off excess plastic parts on both sides of the remaining body. And then once again everything is superfluous from the sides of the blocks we need. As a result of sawing, only the necessary structural element of the DVD drive remains.

Now, using a glue gun, glue the metal beer or lemonade lid to the larger gear. Glue is applied to the edges of the lid. To make it more secure, we go through again with a glue gun around the perimeter of the gluing site.

We heat the body of the helium pen over the candle and bend it at an angle of 90 °. The bend should be done in approximately 1/3 of the handle. When heating it over the candle, do not forget to turn the knob so that it warms up evenly and begins to melt, and does not light up. Lock it in a bent position with your fingers until the plastic cools.

After that, use a glue gun to glue the bent handle to the metal cover on the main unit. We place the handle in this way. So that the longer part is located horizontally, and the short one - vertically. This will be the handle of our charger. We check the performance of the structure.

We take the USB-mother socket and, observing the polarity, we solder it to the terminals of the motor. After that, we fix the socket in any convenient place with hot melt glue.

Our charger is ready, all that remains is to test it. We connect the phone and start turning the handle, while we turn it - the charge goes on, when we stop - there is no charge.

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