4-2 Chapter 4: Problem Isolation Procedures
Hardware Component Descriptions
Video Input/LVDS Output Circuits – Controller PCB
This is not a serviceable part and, if a fault is suspected here, the PCB should be replaced.
This board is responsible for processing the video signal for input into the LCD panel and
controlling the backlight brightness setting (as per the setting in the OSD) and on/off signal
(for switching to power save mode). The board also stores user settings.
Power to the board is supplied by a USB+Power cable. When power is present on the board
the dual color LED will light. It is initially amber, and then turns green when a valid video
input is detected on either the VGA or DVI input.
If the LED remains amber when a video signal is present check the video lead and the signal
source. If the LED does light at all check the power to the board (CN6/CN17).
EDID
Note that the host will only be able to read EDID data from a powered down monitor if 5V is
supplied by the host on pin 9 of the D-sub connector or pin 14 of the DVI connector
(depending on which video input is used). Note that the two video inputs have independent
EDID’s, though both should contain identical timing and product information.
USB Hub – Controller PCB
This is not a serviceable part and, if a fault is found here, the PCB should be replaced.
The USB hub requires power to be applied to the monitor. If the hub itself or connected
devices are not registering on the host PC check that the upstream connection (USB+Power) is
connected correctly and the cable is not damaged.
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