Hitachi CP-X940E, Service Manual

Page: 11 / 51

– 11 –
+1
-0
4-3-3 The luminance adjustment.
Use Minolta CL-100 at measurement and adjustment.
1. Maximize CONTRAST and BRIGHT in the picture
menu.
2. Use the XGA VESA(60) timing signal to input a
0.7Vpp green primary signal and measure the
luminance at the center of the image. Suppose the
reading is “A”.
3. Normalize CONTRAST and BRIGHT in the picture
menu.
4. Use the XGA VESA(60) timing signal to input a
0.21Vpp green primary signal. Adjust the luminance
with SUB-BRIGHT - W to
Ax0.09 10 [lx].
5. Use the XGA VESA(60) timing signal to input a
0.7Vpp green primary signal. Adjust the luminance
with SUB-CONTRAST - W to
Ax0.95 20 [lx].
6. Return to procedure 4 to check the luminance is
within the specification. If it is out of the
specification, repeat the procedure 4 - 5.
7. Use the XGA VESA(60) timing signal to input a
0.0Vp-p black pattern. Adjust the luminance with
DAC_P - BLACK2-POSI - W to
Ax0.009 [lx].
8. Use the XGA VESA(60) timing signal to input
0.7Vpp 16 step gray scale signal. See the two
darkest steps if they can be distinguished. Use
DAC_P - BLACD2-POSI - G in order to make a
little different luminance between 1st step and 2nd
step by visual check. (See Fig.4-5.)
1st step
2nd step
Fig.4-5 16 step gray scale