الأجهزة اللازمة لإصلاح وضبط الجهاز التلفزيوني الأحادي اللون والملون ٣_a

2- Check for leakage or shortness.

3- Examine the color screen electron ejector.

4- Examine and determine whether the screen is damaged or whether it is intact.

E - Checking the continuity of the focus elevator. What this device can do is:

1- Fixing the presence of shortness in the screen poles.

2- Clean and balance the launcher.

3- Resuscitation of the runway.

It is noted that the device contains three gauges, each measuring device belongs to one of the launchers of the color screen independently - and the device shows, with determination, that there is a leakage between two cathodes. Or between the cathode and the heater, or between Grid G ​​and the cathode

Note: Practical experiments have shown that more than 95% of screen refresh operations have returned the screen as new.

11- Screen valve lighting device:

This device is designed for color TV and monochrome black and white. It can be used to resuscitate the old screen valve. There are two types of screen valve lighting devices, which are shown in Figure (15-21).

1 - The bias network control unit and the shape is dedicated to the color screen - and it has the ability to independently adjust the bias (G) to (G2) for each launcher, and this device does not strengthen the heater voltage.

2 - The screen heater voltage booster unit and shape (also dedicated to the color screen) and it works by increasing the voltage of the screen filament heater feeding) from 20 to 25%. The heater (filament) is fed from a special isolation transformer between its primary and secondary coils. Thus, the heater circuit is separated and isolated from the cathode - connected through the ground. These devices are designed so that they have a base suitable for the types of valves, connection method, voltage and current of the heater filament, whether it is parallel or serial.

12- High Voltage Probe:

The high-voltage probe can be used as a measuring conductor for a regular or digital ohmmeter - Figure (16-21) - which increases the ability to measure DC current up to 40,000 volts, as shown in the figure, and the device in Figure B can measure a voltage greater than (40,000 volts). . The insulating cover for this probe is thermoplastic, i.e. thermoplastic, and has high insulators.

The four cylindrical barriers are seen to increase the isolation of the user's hand. So that the insulation resistance reaches up to (1000 mega ohms). In all cases, these items must be used by a specialized technician only, and it is preferable to refer to the instructions of the device and adhere to them to avoid the risk of potential electric shocks.

12- The experimental alternative voter:

To detect and determine the presence of a fault in the TV’s voter, this alternative voter uses Figure (17-21), which is powered by AC power or by 9-volt batteries and works with solid elements, and its functions are as follows:

1- Substitute VHF voter 2

2- Checking the UHF elector by feeding the device the output of the (UHF elector) with a signal (40 MHz), internal amplification (position of the switch on channel 1).

3- Image IF stage alternative - Image Detector The image signal amplification stages.

4 - An alternative to the sound limiter - the sound detector - stages of amplification of the sound signal. Other models of the device may contain various specifications, including an alternative to the (UHF, VHF) range - and all devices operate with batteries in addition to AC electric current for some of them.