2 - Apple Cinema Display (20-inch)
Symptom Charts
5. To check whether the LCD is working:
• Press the launch button on the display which will bring up the Display Preferences
window (if the screen is blank you will not see the window). Shine a bright light
such as sunlight or a high intensity lamp (see Important note, below) into the
screen and at the same time notice whether you can see a faint image of the
Display Preferences window or other desktop items on the screen.
– If desktop items can be seen, the LCD panel is working. The problem may be with
the inverter board or related cables or connectors. Continue with the
troubleshooting steps.
– If no desktop items can be seen, the problem may be with the LCD panel or the
main board or related cables or connectors.
Important: Lights get very hot and can quickly damage the display; be extremely
careful not to allow too much heat next to the screen or other parts of the display and
do not allow the light fixture to touch the screen, or damage can result.
6. 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 at TMDS, Panel Power, J1, J2, J3, J4, J6, J7 and J8.
Note: Refer to the Block Diagram in this manual for connector locations.
7. Plug the display into a known-good computer, then boot the computer.
8. Connect the ground lead of a volt meter to the metal chassis of the display, then check
the following:
• At J1, verify +24-28V at pin 1 (pin 4 is ground). If not, replace ADC cable.
• At J3, verify +18V at pin 6. If not, replace the main board.
• At J4, verify +5V at pin 1. If not, replace the main board.
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