- 5 -
Specific value of V AMP 50 depends on type picture tube.
* The parameters values are specified during adjusting operations.
- Uncontrolled parameters
The values of parameters should be set as shown in table.
To exit from service mode you should press the service key.
Check value of high voltage. The voltage should be not less than 20.5 kV at maximal brightness
and contrast. The high voltage should not exceed 26.5 kV at 100 µA of current. When current
through picture tube changes from 900 µA to 100 µA, the change of high voltage should not
exceed 10 % and the size change of picture should not exceed 12 mm along the vertical and 16
mm along the horizontal. The current through the tube should be over the range 700 - 950 µA.
Switch on 0.5SJ+0.5JB signal. Evaluate visually the quality of SJ signal. The bars shoul be located
in this way: white, yellow, bluish, green, purple, red, blue, black. During change of brightness the
line of flyback should not appear.
Switch on TEXT signal. Evaluate visually the quality of the signal.
NOTE. During control youl sold pay attention if three main colours - red, blue and green - present
in teletext. Take technological remote control ir switch TV board to AV1 mode. (Red key).
Depending on trasmited signal, a programme should presen on monitor screen.
Check if sound passes to TV board through SCART connector in mode AV by regulating soun
from min to max.
Press the red key on remote control and switch the board to the television mode. Range of video
signal on SCART connector should be equal 1+0.1 V (complete range)when measuring by
osciloscope on adapter pins. The oscilloscope picture of sound shoud present on both adapter
pins.
Corection of field clarity and beam convergence are made after loosening of MSS fixig ring and by
rotation the rings of clear field and static convergence. The correction of dynamic convergence in
corners is made by inserting additional shunt under the beam deflection system. After finding of
correct position, the shunt should be glued to the cone of picture tube. Dynamic convergence
should be made at the repairee workplace.
Half of coloured, half of white and black bars - evaluation of sound and picture quality of english
stadard (I)
Press the TXT key on remote control. The teletext page with number 100 should appear on the
screen. Check it visually if there are no any picture defects on it. Pres the AUTOSTORE or AV key
on remote control. The page with number 101 should appear on the screen. Check it visually if
there are no any errors and picture defects on it.Switch off the teletext by presiing TXT key.
Checking of remote control keys and AV1-AV2-RGB modes (red key).
Pull out aeriak and check if the sound is blocked and the screen is blue. The pictute and sound
should be restored after connectin of the aerial. Assure that TV set does not radiate noises in
any mode.
Leave: BRIGHTNESS-31, CONTRAST-50, SATURATION-31, SOUND-0.
Field clarity. Beam convergence