Hitachi CP-X2520 Service Manual page 10

4-8 Black uniformity adjustment
This adjustment improves color uniformity in a
black solid image.
Preparations
1. Perform this adjustment after the adjustments
described in the section 4-7.
2. Open the FACTORY MENU and select GAMMA.
Press ►(right) or ENTER key to switch the
menu, and then select the GAMMA menu with
the ▲(up) and ▼(down) keys.
GAMMA menu
GAMMA No.0 R0
3. In this adjustment, you can change the values
for R, G and B of No.0. Use the ◄(left) and
►(right) keys to move to cells for R, G and B,
and use ▲(up) and ▼(down) keys to change
each of values.
ATTENTION
● Make sure that the GAMMA menu says No.0 on
the second cell from the left. If not, select the
cell and press ▼(down) keys to No.0.
● The operation at the cell for W is not necessary
since it affects values of R, G and B.
NOTE: The number of W will automatically change
according to the numbers of R, G and B.
Adjustment procedure
1. Set the values of R, G and B of No.0 at 0 (zero)
and check the image on the screen with a black
solid pattern.
2. Set the values of R, G and B of No.0 at 350,
500, 700 and 900, in order of number from
smallest, and observe changes of black images
on the screen. Find the number where the black
image become better, and set the values of R,
G and B at the number.
NOTE: Set the values of R, G and B at the same
number.
Example for setting at 500:
GAMMA No.0 R500
└───────────────┘
Set at the same number
CP-X2520 ( M2-25ED ) / CP-X3020 ( M2-30ED )
G0 B0 W0
G500 B500 W500
3. Check the contrast level with test patterns like a
grayscale before finishing this adjustment. If it
is worse than your permissive level, reset the
values of R, G and B at a smaller number.
NOTICE
The bigger the number of R, G and B of No.0
is, the better the black solid image become. On
the other hand, there is a trade-off between the
improvement of the black solid image and the
deterioration of the contrast.
10