Apple Cinema Display 22" (ADC) Troubleshooting - 3
Symptom Charts
Partially dim screen
This symptom indicates a problem with the inverter or backlight bulbs (on the side of the
display that is dim), or related cables or connectors. This may be caused by the backlight
bulbs or the inverter not working properly.
1. Plug the display into a known-good computer with a known-good video card and ADC
display port. Boot the computer.
2. Notice whether the power button on the display is flashing, two short flashes then a
long flash, in a delayed repeating pattern. This indicates trouble with either the
inverter, backlight bulbs or related cables or connectors (this indicator may not always
be exhibited). With this in mind, continue with the troubleshooting steps to determine
the problem.
3. Warning: The inverter board generates high voltage when the display is plugged
in. Do not touch the inverter board components, pins or connectors, when the
display is connected to the computer.
Disconnect the display from the computer, then open the display and check for
secure connections where the backlight bulbs plug into the inverter.
Note: Refer to the Block Diagram in this manual for connector locations.
4. Important: The backlight bulbs are extremely delicate. Handle with care.
To determine whether the problem is with the backlight bulbs or the inverter board,
disconnect the two CN connectors to the backlight bulbs on the side that is dim.
Connect the CN connectors to a known good backlight bulb tray (the bulb tray from
the other side of the display can be removed and plugged in to test, if known good).
Connect the display’s ADC connector to a known-good computer, then boot the
computer. If one or more of the bulbs does not light, replace the inverter. If the bulbs
light correctly, the original backlight bulb tray is bad, replace the bulb tray.
Note: The top and bottom backlight bulb trays are interchangeable. The bulb trays
are not specific to the top or bottom.
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