Why is the line transformer so expensive?

In order for an image to appear on the screen of the kinescope and the viewer can enjoy his favorite programs, it is necessary to direct an electron beam that traces the entire area. The principle of the monitor or TV, on which the display element is a cathode-ray tube, is easier to describe with the example of black and white equipment.

So, the image on the screen is formed by only one point, with a high frequency of scanning hundreds of lines. The general picture we see because of the inertia of our vision.

In addition, in order for the image to be dynamic, it is also necessary to change the frames. The electron beam runs a line after line from top to bottom and returns again because it is driven by a magnetic field created by the windings of the deflecting system. In order for this to happen, it is necessary to change the current in it with a certain regularity.

The classical scheme of the TV includes various nodes: power, line and frame scanning, a radio channel, a control unit, a low-frequency amplifier and a color module, if the receiver is a color one. The main element of the horizontal scan unit is a line transformer. In modern TVs, it is usually combined with a voltage multiplier. Its purpose is to obtain sawtooth pulses of electric current, which are fed to the windings of the deflecting system. A voltage multiplier mounted in the same housing as a line transformer generates a high, up to 27 kilovolts, accelerating voltage, which ensures the acceleration of electrons in their motion to the screen mask coated with a phosphor. It, in turn, is fed to the kinescope by means of a high-voltage insulated input with a so-called "bump", which protects the contact from breakdown on the housing.

A horizontal scan transformer, mounted together with a multiplier (TDX), has several windings that form additional control signals. These include adjustable focusing and the magnitude of the accelerating voltage, as well as the winding of the blanking of the beam, which should not be visible on the screen.

So, two groups of windings of the deflecting system ensure the scanning of the raster vertically (HR, HR) and horizontal (horizontal, SR). As a result, its shape is very close to rectangular, but does not quite fit it. This deviation is due to the difference in distance that the electrons have to overcome on the way to the mask. The closer to the edge of the screen, the greater it is, and CRTs with flat screens suffer this defect more than their "convex" counterparts. A string transformer in combination with a multiplier and a deflection system is an object of careful regulation and adjustment, after which distortions become minimal.

The requirements for the quality of TDX are very high, the length of the correct operation of the entire television receiver depends on it. Line transformers are structurally implemented in the form of assembled and repaired assemblies and are not subject to repair, therefore all internal contacts between the windings should be very reliable.

The SR node spends most of the energy consumed by the TV, up to half its entire value.

Like any inductive device, the line transformer has a magnetic core serving as the core on which the coils are put on. In order to reduce the size, it is made of a special ferrite with a high magnetic conductivity.

For all these reasons, TDKS is the most expensive spare honor after the kinescope, the need for which can arise during the repair of the TV.