Setting Constant Brightness Circuit (Factory Mode); Reading Beam Current Default Data; Confirming Constant Brightness Function; Adjusting The Rgb Drive Signal - NEC DPro2070SB Service Manual

2.4.5

Setting CONSTANT BRIGHTNESS circuit (Factory mode)

Note) This operation should be carried out after the adjustment of cut-off. In addition, heat-
running should be fully carried out.
2.4.5.1

Reading beam current default data

(1) Input timing No. 12 (106.25kHz/85Hz, 1600x1200) crosshatch signal with the signal generator.
(2) Select CONSTANT BRIGHTNESS and push (-) button, then it starts to read the beam
current default data.
(3) When the reading is completed, OSM standard voltage DAC (Digital Analog Converter)
data and the beam current default data of each color (R/G/B) are indicated. Then, confirm
that the data is within the following value range.
Standard voltage DAC data
Red beam current default data
Green beam current default data
Blue beam current default data
(4) If the above data could not be within the value range specified in (3) above, carry out steps
(2) and (3) mentiond above once.
(5) Measure the luminance and color coordination of the back raster.
2.4.5.2

Confirming CONSTANT BRIGHTNESS function

(1) Select COSTANT BRIGHTNESS. Push (+) button, and it decrements the BRIGHTNESS
data to imitate the deteriorated condition due to elapsed time, then compensation function
starts to operate.
(2) Measure the color coordination and luminance of the back raster after compensation.
Compare them to the data measured in 2.4.5.1 (5) to confirm that the differences are within
the following value range.
Color coordination of x and y
Luminance
(3) If the color coordination and Iuminance of the back raster could not be within the value
range specified in (2) above, select CONSTANT BRIGHTNESS and push RESET button,
then carry out step 2.4.5.1 (2) once.
(4) Select CONSTANT BRIGHTNESS, and push RESET button.
2.4.6

Adjusting the RGB drive signal

2.4.6.1

Adjusting GN1 (GAIN-H) (adjustment of 9300K)

Adjustment item
Status
GN1 (GAIN-H)
indicator
(1) Input the following adjustment timing with the signal generator.
Pattern: Full white (Input amplitude = 0.7Vp-p)
Adjustment timing: No.12 (106.25kHz/85Hz, 1600x1200)
(2) Select CONTRAST with OSM, and set to MAX using (+) button.
(3) Select BRIGHTNESS, and set the data to 7F using (-) (+) buttons.
(4) Output the solid color for the picture from Signal generator A, and input GREEN only.
(5) Set G-GN1 (G-GAIN-H) with OSM, and adjust the luminance of full green picture to the
specified value listed in the following table with (-) (+) buttons.
(6) Input BLUE, RED and GREEN, and select B-GN1 (B-GAIN-H), R-GN1 (R-GAIN-H) and G-
GN1 (G-GAIN-H) appropriately, then adjust each data to the specified value listed in the
following table with (-) (+) buttons.
(7) Confirm that the variation of the color coordination data of x and y is within +/- 0.015 when
CONTRAST is set to 25cd/m
: 50-F0 (HEX)
: 73-8C (HEX)
: 73-8C (HEX)
: 73-8C (HEX)
: within +/- 0.020
: within +/- 0.05cd/m
Adjustment mode/set
Factory
2 with OSM.
2 - 13
2
Imput signal/pattern
No. 12:106.25kHz / 85Hz, 1600x1200
Full white