How to change the output voltage of the tdx. A simple powerful kacher on a line transformer

One or more high-voltage leads come out of the transformer. They are in thick insulation to prevent high voltage from flashing to other electronic components. A “suction cup” is attached to the main terminal, which is the thickest due to the insulation. This is a contact, insulated with a rubber casing, connected to the kinescope.
However, there are other types of these transformers - older ones. They do not have such a plastic body, and the coil itself is filled with epoxy resin. Old samples still have legs for soldering them into the board, but they do not have regulators. The main difference between the old models and the new ones is that they do not have a built-in multiplier - a device that increases the output voltage and rectifies it, and the high-voltage output is made in the form of a tap from the coil for subsequent soldering.
Application
Explanation TDKS - diode-cascade line transformer. His main task– generate a kinescope supply voltage of about 30 kilovolts. They just go along the thickest wire to the “suction cup”. However, it also generates reverse pulses for the damping system, generates auxiliary voltages and powers the kinescope filament. Both the tuner and video amplifiers are powered from it. Depending on the design, the line transformer can also generate other auxiliary voltages.
Device
It’s worth noting right away that there are two main types of transformers: TVS - stands for Output Line Transformer and TDKS. Their fundamental difference is that the fuel assembly is not equipped with a built-in voltage multiplier, and its output contains alternating current. Separate multipliers are produced for fuel assemblies.
Like any other transformer, a line transformer has a primary coil - voltage is applied to it and, based on it, an alternating current appears at the terminals of the secondary coil of the transformer by means of electromagnetic induction. The magnetic core in this case is ferrite - a special material that is used not only in the production of line transformers.
Why was ferrite chosen rather than iron plates? Due to the fact that the transformer operates at a high frequency, at which an iron core simply could not work. The magnetic core is made in the form of two U-shaped halves without a gap, connected by a metal bracket.

The TDKS contains a multiplier consisting of high-voltage diodes and capacitors connected in a certain way. Its main task is to multiply and rectify voltage.
Replacement
A line transformer can fail for various reasons. The most common of them:

1. Breakdown on the transformer housing - violation of the insulation of the line transformer. Expressed as a burnt hole on the body.
2. Damage to the coil - wire break or inter-turn short circuit of the coil.
3. Mechanical damage to the transformer, which leads to damage to the coil and/or wire rupture and/or interturn short circuit and/or damage to the magnetic circuit.

In all cases, the transformer must be replaced. It is important to remember that the transformer can only be replaced with a similar one. Transformers may not differ in appearance, but in terms of the terminal arrangement they can differ radically.

This article answers the questions: how to test a pulse transformer And how to check TDKS .

Method No. 1

To check functionality transformer You will need an oscilloscope and a sound generator with a frequency range from 20 kHz to 100 kHz. Through a capacitor with a capacity of 0.1-1 μF, a sinusoidal pulse with an amplitude of 5-10 V is applied to the primary winding of the converter being tested. The signal from the secondary winding is measured by an oscilloscope connected to it. If the sinusoidal signal is not distorted in any part of the frequency range, then the transformer being tested is operational. A distorted sine wave indicates a malfunction of the converter. Figure 1 schematically shows the connection method. Figure 2 shows the shape of sinusoidal signals.

Rice. 1. Connection diagram of the transformer under test (method No. 1)

Rice. 2. Sinusoidal waveforms (method No. 1)

Method No. 2

To check the serviceability of the pulse transformer using this method, first you need to connect a capacitor with a capacity of 0.01-1 μF in parallel to the primary winding and, using an audio frequency generator, apply a signal with an amplitude of 5-10 V to the winding. Next, by changing the frequency of the generator signal, you need to create a resonance in a parallel-connected oscillatory circuit and, using an oscilloscope, monitor the pulse amplitude. If the secondary winding in a working converter is closed, the oscillations in the circuit will stop. From which we can conclude that due to a short circuit in the turns, the resonance in the oscillatory circuit is disrupted. Therefore, if there are short-circuited turns in the transformer under test, regardless of the signal frequency, there will be no resonance. The connection diagram for all elements is shown in Figure 3

Rice. 3. Connection diagram of the transformer under test (method No. 2)

Method No. 3

This method transformer checks the same as the previous one, but with a slight difference: the connection of the capacitor is not parallel, but serial. If there are short-circuited turns in the transformer winding, when resonant frequency the oscillations in the circuit break and it will be impossible to cause resonance in the future.

The connection method is shown schematically in Figure 4.

Rice. 4. Connection diagram of the transformer under test (method No. 3)

Method No. 4

The previous three methods are better for testing the isolation transformer and power transformer, and check the functionality of the TDKS converter These methods can only be used to approximate. The suitability of a line transformer can be assessed as follows.

A rectangular frequency pulse of 1-10 kHz with a small amplitude should be sent through the collector winding of the converter being tested (the output signal is suitable for calibrating an oscilloscope). You need to connect the oscilloscope input to the same place and, based on the resulting image, you can draw conclusions. If TDSC is working, then the amplitude of the observed differentiated signals will be approximately the same as the original rectangular pulses. If there are short-circuited turns in the transformer, short differentiated signals with an amplitude several times lower than that of the original rectangular pulse will be visible in the picture.

This verification method is considered rational, since only one measuring device is needed to test TDKS. But it is also worth considering that not all oscilloscopes are equipped with a generator output, which is used to calibrate the device. For example, the fairly common oscilloscopes S1-94 and S1-112 are not equipped with a separate calibration generator. To solve this problem, you can independently assemble a simple generator that can fit on one chip. In addition, it is not difficult to install it in the oscilloscope housing, which will ensure quick and effective testing of TDKS transformers. The generator assembly diagram is shown in Figure 5.

Rice. 5. Generator circuit (method No. 4)

The assembled generator is installed inside the oscilloscope in any suitable place, power is supplied from the 12 V bus. It is more convenient to use a dual-type toggle switch (P2T1-1V) as a switch, which is best placed on the front of the device, next to the input connector of the oscilloscope.

Power is supplied to the generator through one pair of contacts, and through the other pair of contacts the input of the oscilloscope itself is connected to the output of the generator. Due to this, in order to check the serviceability of the transformer, it is enough to connect the winding of the converter and the input of the oscilloscope with a simple signal wire.

Method No. 5

This method describes checking TDKS for interturn short circuits and breaks in windings without using a generator. Before testing the converter, you need to disconnect its output from the power source (110-160 V). Next, using a special jumper, you need to close the collector of the horizontal output transistor with the common wire. After that, the power supply unit along the 110-160 V circuit must be loaded with an electric lamp of 40-60 W, 220 V. Now you should find a voltage of 10-30 V on the secondary windings of the power supply unit converter and pass it through a transistor, with a resistance of 10 Ohms, to the disconnected terminal TDKS. The resistor signal is monitored by an oscilloscope. If the transformer being tested has interturn short circuits, then the image will look like a “dirty fluffy rectangle”, and the main part of the voltage will drop across the resistor. If there are no short circuits, then the rectangle pattern will be clean, and the drop in the electrical signal across the resistor will be no more than a few fractions of a volt.

By monitoring the signals on the secondary windings, you can find out whether the transformer is working or not. If the picture shows a rectangle, then the winding is intact; if there is no rectangle, the winding is broken. Next, you need to remove the resistance resistor (10 Ohms) and attach a load of 0.2-1.0 kOhm to all secondary windings of the TDKS. If the output image is the same as the input, then the TDKS transformer is working.

Seal

TDKS, what is it? To put it simply, it is a transformer hidden in a sealed casing, since the voltages in it are significant and the casing protects nearby elements from high voltage. TDKS is used in line scanning of modern televisions.

Previously, in domestic color and black-and-white televisions, the voltage of the second anode of the kinescope, accelerating and focusing, was generated in two stages. Using a TVS (high-voltage line transformer), an accelerating voltage was obtained, and then using a multiplier, the focusing voltage and voltage for the second anode of the cathode were obtained.

TDKS has the following decoding - a diode-cascade horizontal transformer, generates a supply voltage for the second anode of the kinescope of 25 - 30 kV, and also generates an accelerating voltage of 300 - 800 V, a focusing voltage of 4 - 7 kV, supplies voltage to video amplifiers - 200 V, tuner - 27 31 V and on the filament of the kinescope. Depending on the TDKS and the construction scheme, it generates additional secondary voltages for frame scanning. From the TDKS, the signals for limiting the current of the kinescope beam and automatic adjustment of the horizontal scanning frequency are removed.

Let's consider the TDKS device using the example of TDKS 32-02. As befits transformers, it has a primary winding, to which the horizontal scan supply voltage is supplied, and also the power for the video amplifiers and secondary windings are removed to power the circuits already mentioned above. Their number may vary. The second anode, focusing and accelerating voltage are powered in a diode-capacitor cascade with the ability to adjust them with potentiometers. Another thing that should be noted is the location of the terminals; most transformers are U-shaped and O-shaped.

The table below shows the pinout of TDKS 32 02 and its diagram.

Numbering begins when looking from below, from left to right, clockwise.

Replacement

It is difficult to select analogues for the required TDKS, but it is possible. You just need to compare the characteristics of the existing transformers with the required one, in terms of output and input voltages, as well as in the matching of the terminals. For example, for TDKS 32 02 the analogue is RET-19-03. However, although they are identical in voltage, the RET-19-03 does not have a separate grounding terminal, but this will not create problems, since it is simply connected inside the case to a different terminal. I am attaching analogues for some tdks

Sometimes it is not possible to find a complete analogue of TDKS, but there is a similar one in voltage with a difference in the conclusions. In this case, after installing the transformer in the TV chassis, you need to cut the mismatched tracks and connect them in the required sequence with pieces of insulated wire. Be careful when performing this operation.

Breakdowns

Like any radio component, line transformers also break. Since the prices for some models are quite high, it is necessary to make an accurate diagnosis of the breakdown so as not to throw money away. The main malfunctions of TDKS are:

• breakdown of the housing;
• winding breakage;
• interturn short circuits;
• screen potentiometer break.

With breakdown of the housing insulation and breakage, everything is more or less clear, but an interturn short circuit is quite difficult to identify. For example, TDKS beeps; this can be caused both by the load in the secondary circuits of the transformer and by an interturn short circuit. The best thing is to use a device to check TDKS, but if there is none, look for alternative options. You can read about how to check the TDKS of a TV in the article on the website “How to check a transformer.”

Recovery

A breakdown is usually a crack in the housing; in this case, repairing the TDKS will be quite simple. We clean the crack with coarse sandpaper, clean it, degrease it and fill it with epoxy resin. We make the layer thick enough, at least 2 mm, to prevent repeated breakdown.

Restoring the TDKS in the event of a break or short circuit of the turns is extremely problematic. Only rewinding the transformer can help. I have never performed such an operation, since it is very labor-intensive, but if desired, of course, everything is possible.

If the filament winding breaks, it is better not to restore it, but to form it from another place. To do this, we wind a couple of turns of insulated wire around the TDKS core. The direction of winding is not important, but if the filament does not light up, swap the wires. After winding, you need to set the filament voltage using a limiting resistor.

If the accelerating voltage (screen) is not regulated, then in this case it can be formed. To do this, you need to create a constant voltage of about 1kV with the possibility of adjusting it. This voltage is present on the collector of the horizontal transistor; the pulses on it can be up to 1.5 kV.

The circuit is simple, the voltage is rectified by a high-voltage diode and regulated by a potentiometer, which can be taken from the kinescope board of an old domestic TV 2 or 3USTST.

From this article you will learn how to get high voltage, high frequency with your own hands. The cost of the entire structure does not exceed 500 rubles, with a minimum of labor costs.

To make it, you will need only 2 things: - an energy-saving lamp (the main thing is that there is a working ballast circuit) and a line transformer from a TV, monitor and other CRT equipment.

Energy saving lamps (correct name: compact fluorescent lamp) are already firmly established in our everyday life, so I think it won’t be difficult to find a lamp with a non-working bulb, but with a working ballast circuit.
The CFL's electronic ballast generates high frequency voltage pulses (typically 20-120 kHz) that power a small step-up transformer, etc. the lamp lights up. Modern ballasts are very compact and easily fit into the base of the E27 socket.

The lamp ballast produces voltage up to 1000 Volts. If you connect a line transformer instead of a lamp bulb, you can achieve amazing effects.

A little about compact fluorescent lamps

Blocks in the diagram:
1 - rectifier. It converts alternating voltage into direct voltage.
2 - transistors connected according to the push-pull circuit (push-pull).
3 - toroidal transformer
4 - resonant circuit of a capacitor and inductor to create high voltage
5 - fluorescent lamp, which we will replace with a liner

CFLs are produced in a wide variety of powers, sizes, and form factors. The greater the lamp power, the higher the voltage must be applied to the lamp bulb. In this article I used a 65 Watt CFL.

Most CFLs have the same type of circuit design. And they all have 4 connection pins fluorescent lamp. It will be necessary to connect the ballast output to the primary winding of the line transformer.

A little about line transformers

There are also linemen different sizes and forms.

The main problem when connecting a line reader is to find the 3 pins we need out of the 10-20 they usually have. One terminal is common and a couple of other terminals are the primary winding, which will cling to the CFL ballast.
If you can find documentation for the liner, or a diagram of the equipment where it used to be, then your task will be significantly easier.

Attention! The liner may contain residual voltage, so be sure to discharge it before working with it.

Final design

In the photo above you can see the device in operation.

And remember that this is constant tension. The thick red pin is a plus. If you need alternating voltage, then you need to remove the diode from the liner, or find an old one without a diode.

Possible problems

When I assembled my first high voltage circuit, it worked immediately. Then I used ballast from a 26-watt lamp.
I immediately wanted more.

I took a more powerful ballast from a CFL and repeated the first circuit exactly. But the scheme did not work. I thought the ballast had burned out. I reconnected the lamp bulbs and turned them on. The lamp came on. This means it was not a matter of ballast - it was working.

After some thought, I came to the conclusion that the ballast electronics should determine the lamp filament. And I used only 2 external terminals on the lamp bulb, and left the internal ones “in the air”. Therefore, I placed a resistor between the external and internal ballast terminals. I turned it on and the circuit started working, but the resistor quickly burned out.

I decided to use a capacitor instead of a resistor. The fact is that a capacitor passes only alternating current, while a resistor passes both alternating and direct current. Also, the capacitor did not heat up, because gave little resistance to the AC path.

The capacitor worked great! The arc turned out to be very large and thick!

So, if your circuit does not work, then most likely there are 2 reasons:
1. Something was connected incorrectly, either on the ballast side or on the side of the line transformer.
2. The electronics of the ballast are tied to working with the filament, and since If it is not there, then a capacitor will help replace it.

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Books

• Linear transformers of modern TVs. Analogues and characteristics. Collection, Absent. The reference manual provides information about line transformers used in popular foreign TV models. The operating principle of TDKS in the output stage of a horizontal line is described...