Chroma Gain Adjustment [For Type S/Se] - Hitachi VK-S274 Service Manual

7.4 Chroma Gain Adjustment
Incompleted Phenomenon:
Color of the picture is denser than that of the subject.
Color of the picture is lighter than that of the subject.
Test Point:
Video Out (PG1601-6)
Equipment/Jig:
Oscilloscope or Vectorscope
C12 light balance filter
Condition:
Attach a C12 light balance filter to lens
Point the at a color bar chart.
Procedure:
1) Input 4 to PC on the adjustment menu screen.
2) The chroma gain adjustment screen will appear.
3) When using an oscilloscope (Fig. 7-2):
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. 7-3, 7-4):
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.
RED
BURST
100 %
Fig. 7-3 [For TYPE S]
3 - 10
[For TYPE S/SE] (Figs. 7-2, 7-3, 7-4)
RED
620 mV
± 20 mV
Fig. 7-2
RED
BURST
220 %
± 5 %
100 %
Fig. 7-4 [For TYPE SE]
Adjustment menu
***********************************************************
ADJUSTMENT
***********************************************************
[1] AUTO IRIS CONTROL
[2] MATRIX
[3] WHITE BALANCE
[4] CHROMA GAIN
[ESC] RETURN TO MAIN MENU
Please select [1] - [3] or [ESC]
Input 4.
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
When using an oscilloscope
Set the red level on waveform to 620 mV
± 20 mVp-p.
When using a vectorscope
Set the red vector to 220 % ± 5 % of
burst vector.
Press Enter key.
Chroma gain data write
<< ADJUSTMENT OF CHROMA GAIN >>
DATA WRITING INTO EEPROM
Chroma gain adjustment complete
<< ADJUSTMENT OF CHROMA GAIN >>
ADJUSTMENT FINISHED
PRESS ANY KEY
Press any key.
220 %
± 5 %