After rummaging around on the Internet and reading more than one article and discussion on the forum, I stopped and started disassembling the power supply. I must admit, the Chinese manufacturer Taschibra has released an extremely high-quality product, the circuit diagram of which I borrowed from the site stoom.ru. The circuit is presented for a 105 W model, but believe me, differences in power do not change the structure of the circuit, but only its elements depending on the output power:
The circuit after the modification will look like this:
Now in more detail about the improvements: 
If a different output voltage is required, the secondary winding of the power transformer will have to be rewinded. The diameter of the wire (harness of wires) is selected based on the load current: d=0.6*root(Inom). My unit used a transformer wound with wire with a cross-section of 0.7 mm²; I personally did not count the number of turns, since I did not rewind the winding. I unsoldered the transformer from the board, unwound the twisted wires of the secondary winding of the transformer, there were 10 ends in total on each side:
I connected the ends of the resulting three windings together in series into 3 parallel wires, since the cross-section of the wire is the same 0.7 mm2 as the wire in the transformer winding. Unfortunately, the resulting 2 jumpers are not visible in the photo.
Simple mathematics, a 150 W winding was wound with a 0.7 mm2 wire, which we managed to split into 10 separate ends, ringing the ends, divided into 3 windings each with 3+3+4 cores, turn them on in series, in theory you should get 12+12+12= 36 Volt.
It turns out that the winding in our transformer is suitable with a large margin. Let me run a little ahead of the voltage that the AC power supply supplied at 32 Volts.
Continuing the redesign of the Taschibra power supply:
Since the switching power supply has current feedback, the output voltage varies depending on the load. When there is no load, the transformer does not start, which is very convenient if used for its intended purpose, but our goal is a constant voltage power supply. To do this, we change the current feedback circuit to voltage feedback.
We remove the current feedback winding and replace it with a jumper on the board. This can be clearly seen in the photo above. Then we pass a flexible stranded wire (I used a wire from a computer power supply) through a power transformer in 2 turns, then we pass the wire through a feedback transformer and make one turn so that the ends do not unwind, additionally pull it through PVC as shown in the photo above. The ends of the wire passed through the power transformer and the feedback transformer are connected through a 3.4 Ohm 10 W resistor. Unfortunately, I did not find a resistor with the required value and set it to 4.7 Ohm 10 W. This resistor sets the conversion frequency (approximately 30 kHz). As the load current increases, the frequency becomes higher.
If the converter does not start, you need to change the winding direction, it is easier to change it on a small feedback transformer.
As I searched for my solution to the conversion, a lot of information has accumulated on Taschibra switching power supplies, I propose to discuss them here.
Differences between similar modifications from other sites:
Taschibra power supplies have been tested for:
To power DC consumers, it is necessary to have a diode bridge and a filter capacitor at the output of the power transformer; the diodes used for this bridge must be high-frequency and correspond to the power ratings of the Taschibra power supply. I advise you to use diodes from a computer power supply or similar ones.
Many novice radio amateurs, and not only those, encounter problems in the manufacture of powerful power supplies. Nowadays, a large number of electronic transformers used to power halogen lamps have appeared on sale. The electronic transformer is a half-bridge self-oscillating pulse voltage converter.Let's consider the circuit diagram of an electronic converter.
The mains voltage is supplied through a fuse to the diode bridge D1-D4. The rectified voltage powers the half-bridge converter on transistors Q1 and Q2. The diagonal of the bridge formed by these transistors and capacitors C1, C2 includes winding I of the pulse transformer T2. The converter is started by a circuit consisting of resistors R1, R2, capacitor C3, diode D5 and diac D6. Feedback transformer T1 has three windings - a current feedback winding, which is connected in series with the primary winding of the power transformer, and two 3-turn windings that supply the base circuits of the transistors.
The output voltage of the electronic transformer is a 30 kHz square wave modulated at 100 Hz.
In order to use the electronic transformer as a power source, it must be modified.
We connect a capacitor at the output of the rectifier bridge to smooth out the ripples of the rectified voltage. The capacitance is selected at the rate of 1 µF per 1 W. The operating voltage of the capacitor must be at least 400V.
When a rectifier bridge with a capacitor is connected to the network, a current surge occurs, so you need to connect an NTC thermistor or a 4.7 Ohm 5W resistor to the break in one of the network wires. This will limit the starting current.
If a different output voltage is needed, we rewind the secondary winding of the power transformer. The diameter of the wire (harness of wires) is selected based on the load current.
Electronic transformers are current-fed, so the output voltage will vary depending on the load. If the load is not connected, the transformer will not start. To prevent this from happening, you need to change the current feedback circuit to the voltage feedback circuit.
We remove the current feedback winding and replace it with a jumper on the board. Then we pass the flexible stranded wire through the power transformer and make 2 turns, then we pass the wire through the feedback transformer and make one turn. The ends of the wire passed through the power transformer and the feedback transformer are connected through two parallel-connected 6.8 Ohm 5 W resistors. This current-limiting resistor sets the conversion frequency (approximately 30 kHz). As the load current increases, the frequency becomes higher.
If the converter does not start, you need to change the winding direction.
In Taschibra transformers, the transistors are pressed to the housing through cardboard, which is unsafe during operation. In addition, paper conducts heat very poorly. Therefore, it is better to install transistors through a heat-conducting pad.
To rectify alternating voltage with a frequency of 30 kHz, we install a diode bridge at the output of the electronic transformer.
The best results were shown, of all the tested diodes, by domestic KD213B (200V; 10A; 100 kHz; 0.17 μs). At high load currents they heat up, so they must be installed on the radiator through heat-conducting gaskets.
Electronic transformers do not work well with capacitive loads or do not start at all. For normal operation, a smooth startup of the device is necessary. Throttle L1 helps ensure smooth starting. Together with a 100uF capacitor, it also performs the function of filtering rectified voltage.
The L1 50 µG inductor is wound on a T106-26 core from Micrometals and contains 24 turns of 1.2 mm wire. Such cores (yellow, with one white edge) are used in computer power supplies. External diameter 27mm, internal 14mm, and height 12mm. By the way, other parts can be found in dead power supplies, including a thermistor. 
If you have a screwdriver or other tool whose battery has expired, then you can place a power supply from an electronic transformer in the battery housing. As a result, you will have a network-powered tool.
For stable operation, it is advisable to install a resistor of approximately 500 Ohm 2W at the output of the power supply.
During the process of setting up a transformer, you need to be extremely careful and careful. There is high voltage on the device elements. Do not touch the flanges of the transistors to check whether they are heating up or not. It is also necessary to remember that after switching off the capacitors remain charged for some time.
After everything that was said in the previous article (see), it seems that making a switching power supply from an electronic transformer is quite simple: install a rectifier bridge at the output, a voltage stabilizer if necessary, and connect the load. However, this is not quite true.
The fact is that the converter does not start without a load or the load is not sufficient: if you connect an LED to the output of the rectifier, of course, with a limiting resistor, you will be able to see only one LED flash when turned on.
To see another flash, you will need to turn off and turn on the converter to the network. In order for the flash to turn into a constant glow, you need to connect an additional load to the rectifier, which will simply take away the useful power, turning it into heat. Therefore, this scheme is used in the case where the load is constant, for example, a DC motor or an electromagnet, which can only be controlled via the primary circuit.
If the load requires a voltage of more than 12V, which is produced by electronic transformers, you will need to rewind the output transformer, although there is a less labor-intensive option.
Option for manufacturing a switching power supply without disassembling the electronic transformer
The diagram of such a power supply is shown in Figure 1.
Figure 1. Bipolar power supply for amplifier
The power supply is made on the basis of an electronic transformer with a power of 105W. To manufacture such a power supply, you will need to make several additional elements: a mains filter, matching transformer T1, output choke L2, VD1-VD4.
The power supply has been operating for several years with a ULF power of 2x20W without any complaints. With a nominal network voltage of 220V and a load current of 0.1A, the output voltage of the unit is 2x25V, and when the current increases to 2A, the voltage drops to 2x20V, which is quite enough for normal operation of the amplifier.
The matching transformer T1 is made on a K30x18x7 ring made of M2000NM ferrite. The primary winding contains 10 turns of PEV-2 wire with a diameter of 0.8 mm, folded in half and twisted into a bundle. The secondary winding contains 2x22 turns with a midpoint, the same wire, also folded in half. To make the winding symmetrical, you should wind it in two wires at once - a bundle. After winding, to obtain the midpoint, connect the beginning of one winding to the end of the other.
You will also have to make the inductor L2 yourself; for its manufacture you will need the same ferrite ring as for the transformer T1. Both windings are wound with PEV-2 wire with a diameter of 0.8 mm and contain 10 turns.
The rectifier bridge is assembled on KD213 diodes, you can also use KD2997 or imported ones, it is only important that the diodes are designed for an operating frequency of at least 100 KHz. If instead of them you put, for example, KD242, then they will only heat up, and you will not be able to get the required voltage from them. The diodes should be installed on a radiator with an area of at least 60 - 70 cm2, using insulating mica spacers.
C4, C5 are made up of three parallel-connected capacitors with a capacity of 2200 microfarads each. This is usually done in all switching power supplies in order to reduce the overall inductance of the electrolytic capacitors. In addition, it is also useful to install ceramic capacitors with a capacity of 0.33 - 0.5 μF in parallel with them, which will smooth out high-frequency vibrations.
It is useful to install an input surge filter at the input of the power supply, although it will work without it. As an input filter choke, a ready-made DF50GTs choke was used, which was used in 3USTST TVs.
All units of the block are mounted on a board made of insulating material in a hinged manner, using the pins of the parts for this purpose. The entire structure should be placed in a shielding case made of brass or tin, with holes provided for cooling.
A correctly assembled power supply does not require adjustment and starts working immediately. Although, before placing the block in the finished structure, you should check it. To do this, a load is connected to the output of the block - resistors with a resistance of 240 Ohms, with a power of at least 5 W. It is not recommended to turn on the unit without load.
Another way to modify an electronic transformer
There are situations when you want to use a similar switching power supply, but the load turns out to be very “harmful”. The current consumption is either very small or varies widely, and the power supply does not start.
A similar situation arose when they tried to put it in a lamp or chandelier with built-in electronic transformers instead. The chandelier simply refused to work with them. What to do in this case, how to make it all work?
To understand this issue, let's look at Figure 2, which shows a simplified circuit of an electronic transformer.
Figure 2. Simplified circuit of an electronic transformer
Let's pay attention to the winding of the control transformer T1, highlighted by a red stripe. This winding provides current feedback: if there is no current through the load, or it is simply small, then the transformer simply does not start. Some citizens who bought this device connect a 2.5W light bulb to it, and then take it back to the store, saying it doesn’t work.
And yet, in a fairly simple way, you can not only make the device work with virtually no load, but also provide short circuit protection in it. The method of such modification is shown in Figure 3.
Figure 3. Modification of the electronic transformer. Simplified diagram.
In order for the electronic transformer to operate without load or with minimal load, current feedback should be replaced with voltage feedback. To do this, remove the current feedback winding (highlighted in red in Figure 2), and instead solder a jumper wire into the board, naturally, in addition to the ferrite ring.
Next, a winding of 2 - 3 turns is wound onto the control transformer Tr1, this is the one on the small ring. And there is one turn per output transformer, and then the resulting additional windings are connected as indicated in the diagram. If the converter does not start, then you need to change the phasing of one of the windings.
The resistor in the feedback circuit is selected within the range of 3 - 10 Ohms, with a power of at least 1 W. It determines the depth of feedback, which determines the current at which generation will fail. Actually, this is the current of short-circuit protection. The greater the resistance of this resistor, the lower the load current the generation will fail, i.e. short circuit protection triggered.
Of all the improvements given, this is perhaps the best. But this will not prevent you from supplementing it with another transformer, as in the circuit in Figure 1.
The electronic transformer is a network switching power supply with very good performance. Such power supplies do not have short circuit protection at the output, but this defect can be corrected. Today I decided to present the entire process of increasing the power of electronic transformers for halogen lamps. We will turn a Chinese electric power supply with a power of 150 watts into a powerful UPS that can be used for almost any purpose. The secondary winding of the pulse transformer, in my case, contains only one turn. The winding is wound with 10 strands of 0.5 mm wire. The power supply is capable of up to 300 watts, therefore, it can be used for low frequencies such as Holton, Lanzar, Marshall Leach, etc. If desired, you can assemble a powerful laboratory power supply based on such a UPS. We know that many UPSs of this type do not turn on without load; Tashibra electronic transformers with a power of 105 watts have this drawback.
Our circuit does not have such a drawback; the circuit starts without load and can work with low-power loads (LEDs, etc.). To make it more powerful, you need to make a few modifications. You need to rewind the pulse transformer, select half-bridge capacitors, replace the diodes in the rectifier and use more powerful switches. In my case, I used one and a half ampere diodes, which I did not replace, but be sure to replace them with any diodes with a reverse voltage of at least 400 Volts and a current of 2 Amps or more.
The device has a fairly simple circuit. A simple push-pull self-oscillator, which is made using a half-bridge circuit, the operating frequency is about 30 kHz, but this indicator strongly depends on the output load.
The circuit of such a power supply is very unstable, it does not have any protection against short circuits at the output of the transformer, perhaps precisely because of this, the circuit has not yet found widespread use in amateur radio circles. Although recently there has been a promotion of this topic on various forums. People offer various options for modifying such transformers. Today I will try to combine all these improvements in one article and offer options not only for improvements, but also for strengthening the ET.
We won’t go into the basics of how the circuit works, but let’s get down to business right away.
We will try to refine and increase the power of the Chinese Taschibra electric vehicle by 105 watts.
To begin with, I want to explain why I decided to take on the powering and alteration of such transformers. The fact is that recently a neighbor asked me to make him a custom-made charger for a car battery that would be compact and lightweight. I didn’t want to assemble it, but later I came across interesting articles that discussed remaking an electronic transformer. This gave me the idea - why not try it?
Thus, several ETs from 50 to 150 Watts were purchased, but experiments with conversion were not always completed successfully; of all, only the 105 Watt ET survived. The disadvantage of such a block is that its transformer is not ring-shaped, and therefore it is inconvenient to unwind or rewind the turns. But there was no other choice and this particular block had to be remade.
As we know, these units do not turn on without load; this is not always an advantage. I plan to get a reliable device that can be freely used for any purpose without fear that the power supply may burn out or fail during a short circuit.
Improvement No. 1
The essence of the idea is to add short-circuit protection and also eliminate the above-mentioned drawback (activation of a circuit without an output load or with a low-power load).
Looking at the unit itself, we can see the simplest UPS circuit; I would say that the circuit has not been fully developed by the manufacturer. As we know, if you short-circuit the secondary winding of a transformer, the circuit will fail in less than a second. The current in the circuit increases sharply, the switches instantly fail, and sometimes even the basic limiters. Thus, repairing the circuit will cost more than the cost (the price of such an ET is about $2.5).
The feedback transformer consists of three separate windings. Two of these windings power the base switch circuits.
First, remove the communication winding on the OS transformer and install a jumper. This winding is connected in series with the primary winding of the pulse transformer.
Then we wind only 2 turns on the power transformer and one turn on the ring (OS transformer). For winding, you can use a wire with a diameter of 0.4-0.8 mm.
Next, you need to select a resistor for the OS, in my case it is 6.2 ohms, but a resistor can be selected with a resistance of 3-12 ohms, the higher the resistance of this resistor, the lower the short-circuit protection current. In my case, the resistor is a wirewound one, which I do not recommend doing. We select the power of this resistor to be 3-5 watts (you can use from 1 to 10 watts).
During a short circuit on the output winding of a pulse transformer, the current in the secondary winding drops (in standard ET circuits, during a short circuit, the current increases, disabling the switches). This leads to a decrease in the current on the OS winding. Thus, generation stops and the keys themselves are locked.
The only drawback of this solution is that in the event of a long-term short circuit at the output, the circuit fails because the switches heat up quite strongly. Do not expose the output winding to a short circuit lasting more than 5-8 seconds.
The circuit will now start without load; in a word, we have a full-fledged UPS with short-circuit protection.
Improvement No. 2
Now we will try to smooth out the mains voltage from the rectifier to some extent. For this we will use chokes and a smoothing capacitor. In my case, a ready-made inductor with two independent windings was used. This inductor was removed from the UPS of the DVD player, although homemade inductors can also be used.
After the bridge, an electrolyte with a capacity of 200 μF should be connected with a voltage of at least 400 Volts. The capacitor capacity is selected based on the power of the power supply 1 μF per 1 watt of power. But as you remember, our power supply is designed for 105 Watts, why is the capacitor used at 200 μF? You will understand this very soon.
Improvement No. 3
Now about the main thing - increasing the power of the electronic transformer and is it real? In fact, there is only one reliable way to power it up without much modification.
For powering up, it is convenient to use an ET with a ring transformer, since it will be necessary to rewind the secondary winding; it is for this reason that we will replace our transformer.
The network winding is stretched across the entire ring and contains 90 turns of wire 0.5-0.65 mm. The winding is wound on two folded ferrite rings, which were removed from an ET with a power of 150 watts. The secondary winding is wound based on needs, in our case it is designed for 12 Volts.
It is planned to increase the power to 200 watts. That is why an electrolyte with a reserve, which was mentioned above, was needed.
We replace the half-bridge capacitors with 0.5 μF; in the standard circuit they have a capacity of 0.22 μF. Bipolar keys MJE13007 are replaced with MJE13009.
The power winding of the transformer contains 8 turns, the winding was done with 5 strands of 0.7 mm wire, so we have a wire in the primary with a total cross-section of 3.5 mm.
Go ahead. Before and after the chokes we place film capacitors with a capacity of 0.22-0.47 μF with a voltage of at least 400 Volts (I used exactly those capacitors that were on the ET board and which had to be replaced to increase the power).
Next, replace the diode rectifier. In standard circuits, conventional rectifier diodes of the 1N4007 series are used. The current of the diodes is 1 Ampere, our circuit consumes a lot of current, so the diodes should be replaced with more powerful ones in order to avoid unpleasant results after the first turn on of the circuit. You can use literally any rectifier diodes with a current of 1.5-2 Amps, a reverse voltage of at least 400 Volts.
All components except the generator board are mounted on a breadboard. The keys were secured to the heat sink through insulating gaskets.
We continue our modification of the electronic transformer, adding a rectifier and filter to the circuit.
The chokes are wound on rings made of powdered iron (removed from a computer power supply unit) and consist of 5-8 turns. It is convenient to wind it using 5 strands of wire with a diameter of 0.4-0.6 mm each.
