Chroma Gain Adjustment - Hitachi VK-S454 Service Manual

(3) Chroma Gain Adjustment (Figs. 5-1, 5-2, 5-3)
Incompleted Phenomenon:
Color of the picture is denser than that of the subjuct.
Color of the picture is lighter than that of the subject.
Equipment:
Oscilloscope or Vectorscope
Test Point:
Video Out (PG1601-6)
Condition:
Atach a C12 filter
Point the at a color bar chart.
Procedure:
1) Input 3 to PC on the adjustment menu screen.
2) The chroma gain adjustment screen will appear.
3) When using an oscilloscope (Fig. 5-1):
Press the D or U key to set the red level on waveform to approx. 620 mVp-p.
Then, while holding down the [Ctrl] key, press the D or U key to set the red level on waveform to approx.
620 mV ± 20 mVp-p.
When using a vectorscope (Figs. 5-2, 5-3):
Press the D or U key to set the red vector to approx. 220% of burst vector.
Then, while holding down the [Ctrl] key, press the D or U key to set the red vector to approx. 220% ± 5% of
burst vector.
4) Press the [Enter] key: The PC display will switch from the chroma gain data write screen to chroma gain
adjustment complete screen.
5) Press any key to restore the adjustment menu screen.
PC Display & Figs
Adjustment menu
***********************************************************
ADJUSTMENT
***********************************************************
[1] AUTO IRIS CONTROL
[2] WHITE BALANCE
[3] CHROMA GAIN
[ESC] RETURN TO MAIN MENU
Please select [1] - [3] or [ESC]

Chroma gain adjustment

<< ADJUSTMENT OF CHROMA GAIN >>
ROUGH ADJUSTMENT
[U] CHROMA GAIN UP
[D] CHROMA GAIN DOWN
FINE ADJUSTMENT
[Crt] + [U] CHROMA GAIN UP
[Crt] + [D] CHROMA GAIN DOWN
[ENTER] SAVE & RETURN TO MENU
[ESC] QUIT
Chroma gain data write
<< ADJUSTMENT OF CHROMA GAIN >>
DATA WRITING INTO EEPROM
3 - 8
Chroma gain adjustment complete
<< ADJUSTMENT OF CHROMA GAIN >>
ADJUSTMENT FINISHED
PRESS ANY KEY
RED
BURST
100 %
Fig. 5-2
RED
Fig. 5-1
RED
BURST
220 %
± 5 %
100 %
Fig. 5-3
620 mV
± 20 mV
220 %
± 5 %