Nokia 446PRO, Service Manual

Page: 23 / 59

446F 21
6. Image performance
Measurement to verify this specification shall be made with equipment that measures the dis-
played image as if it were projected forward onto a flat plane tangent to the center of the CRT
faceplate surface and perpendicular to the Z---axis of the CRT.
Image performance specifications are applicable over specified input power conditions, speci-
fied environmental operating conditions and after being subjected to the specified non---operat-
ing environmental conditions. Before performance measurements the monitor must have been in
room temperature (20+/--- 5 degrees C) for at least 2 hours. After that the monitor must have
been warmed up with power on at least 60 minutes.
The monitor shall be positioned to a magnetic field, which is specified as 0 G horizontal field and
0.45 G vertical field (Northern Hemisphere) when ever the image performance is measured.
If there is no standardised magnetic field available, the monitor should be positioned face to
east.
All image performance specifications will be met in diffuse ambient 500 lux.
All the performance specifications are met when using factory adjusted timing modes within line
frequencies 48 kHz --- 107 kHz.
The timings below 48 kHz line frequency are usable, but not specified.
Performance is optimised for 1280 x 1024, 85 Hz (VESA) resolution.
6.1. Image stabilising time
The image shall begin to be visible in a 500 lux environment within 15 seconds of application of
power and input signals.
The image shall be stabilised within 30 seconds of application of power and input signals. ”Sta-
bilised” means that no significant changes shall occur in the image quality specifications, such
as image brightness, size, linearity and so on.
The image shall reach performance stability within 20 minutes of the application of power and
input signals. ”Performance Stability” means that the display monitor shall meet all of its image
quality specifications.
6.2. Colour temperature and tracking
The default colour temperature is 9300 ˚ K
Measurement conditions:
--- test pattern 50*50 mm white field at the screen centre
--- brightness control adjusted for a background raster luminance level of 1 nit
--- input signals R, G, B with maximum amplitude
When contrast---control is adjusted for 100 nit’s luminance level, the factory adjusted colour
coordinates measured at the screen centre will be:
x = 0.283 +/--- 0.015 = x ref
y = 0.297 +/--- 0.015 = y ref
When contrast---control is adjusted from a luminance level of 100 cd/m2 to
35 cd/m2 or its adjust stop, the colour coordinates measured at the screen centre will be:
x = x ref +/--- 0.015
y = y ref +/--- 0.015