Acer NA23WABAS Service Manual page 13

12 ACER V233H
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1.3.8 Display Communications Channel
The monitor assembly shall provide a display
communications channel that conforms to VESA
DDC2Bi hardware requirements. This configuration
shall contain the 128-byte or 256-byte EDID file as
specified by VESA EDID standard. The monitor should
not write to the EDID file for the first two minutes of
operation following power-up UNLESS some action
taken by the user or the host CPU forces the write (for
instance, requesting the serial number via the OSD).
Furthermore, it is recommended that CMOS switches
be incorporated to isolate the DDC IC from outside
connections while the EDID Fault Management is
being updated. This is to prevent corruption of the
data by attempts to read the data while it is being
changed.
1.3.9 Firmware Update Function (same ISP function)
The update firmware need through from the D-Sub
connector, use DDC I2C bus to do update firmware.
1.4. ELECTRICAL
1.4.1 General Requirements
The panel used as the display device shall be an
1920x1080 resolution 23W, TFT LCD. This panel shall
be approved for use in this monitor.
1.4.2. Panel Timings
The controller included with the monitor shall translate
all video timings from the CPU that meet the timing
requirements listed in Panel specification into timings
appropriate for the panel. Under no circumstances
may the controller supply the panel with timings that
may result in damage . The controller shall insulate
the panel from the CPU , so that the panel shall
always be driven per it's own specification regardless
of the timings being sent from the CPU.
1.4.3.Polarizer Hardness
The outer face of the front polarizer panel shall be
covered with a coating with a # 3 hardness value .
1. Product Specification (continued)
1.4.4.Backlight Requirements
1.4.4.1 General Requirements
1.4.4.2 Lamps Startup Time
1.4.5.Defects
1.4.5.1Visual Inspection
1.4.5.2 Display Degradation
1.4.5.3 Light Leakage
The backlight assembly shall be designed to
support field replacement at the customer site or
authorized service center.The lamps shall have a
continuous operating life of at least 50,000 hours
at 25 . The operating life is defined as having ℃
ended when the illumination of light has reached
50% of the initial value. The lamps shall extend a
sufficient amount from the edge of the light guide
that sputtering over the life of the lamps shall not
cause degradation of the luminance uniformity
(such as non-illuminated bands along the edges
of the display).
The backlight lamps shall start about 2 sec of the
time the monitor power switch is pressed or the
monitor is restarted from a power - down mode .
The starting time shall stay about 2 sec. for the
minimum expected life of the lamps.
Test conditions are as follows :
Ambient Light ----------------------
Temperature--------------------------
Inactive Time -----------------------
The LCD panel shall be inspected with all pixels
set to white, black, red , green , and blue. The
color variation, brightness variation , and overall
appearance must not be perceived as poor quality
.Areas and / or parameters considered
questionable shall be subjected to detailed
measurements .
Over the life of the product , variation of the
parameters specified in Panel specification shall
be maintained within reasonable limits. The panel
must not exhibit any significant defects while in
operation ( excluding the CCFL operation ).This
does not in any way change the warranty given by
the panel manufacturer .
Except for the active display area , there shall be
no light emission visible from any angle from any
other part of the display . For this test , the
ambient illumination must follow panel's
specification.
< 1.0 lux
10 ℃
> 24 hours