الأجهزة اللازمة لإصلاح وضبط الجهاز التلفزيوني الأحادي اللون والملون ٣_a .

7 - Generator of the experimental model of the station:

This device is used as in the previous device, but it is characterized by generating an integrated model that resembles the models of stations because it contains gradations of colors, lines and circles. It almost dispenses with the generator of different models - and modern devices of small size and cost.

The figure shows a model of IF tuning using a rod generator and the appearance of good and bad tuning on the screen in the TV set and on the oscilloscope.

8- Pilot color screen valve:

It is one of the necessary devices for maintenance and repair work, as it dispenses the technician with bringing the broken device to the workshop, as it is a color screen valve and has deflection and matching files and a base for the screen valve so that it can work as a substitute for the color screen with different arrangement of its poles, high voltages and focus (Fig. (12-21).

9 - Check the transistor:

It can examine transistors of all kinds inside and outside the circuit. It has an automatic polarity transistor (NPN) or (PNP), and automatically indicates the type of diode (dual Germanium or silicon), and checks thyristors (SCR) and others.
(21-13).

A - In-circuit check:

Since most of the semiconductor elements are welded to the circuit and it is difficult to disassemble them at every test or check for their safety, so it is useful in effort and time to test them while they are in place. The device has three small clips at the end of the test wires - and they are attached to the poles of the transistor or other elements subject to examination - and the device has a test switch (TEST) with two positions - when a special sound is heard at any position, this indicates the integrity of the element, and this sound is emitted because the element under test constitutes an element Complementary to the audio oscillator circuit in the tester. This test corrects the resistance of a short circuit of not less than (10) ohms. Or a short capacitor higher than 15 microfarads - and there are testing devices that have other specifications.

B - Examination outside the circuit:

And to test the element outside the circuit depends on the current leakage or lack of measurements - and gives the tester device indicator on its board (good or bad). Good or Bad - and reverse leakage can be measured from (1) microampere up to 5mA.

10- Screen valve treatment and activation device:

This device can perform the following functions:

1- Check the emission of the cathode.

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