Apple led cinema display 24inch User Manual

LED Cinema Display (24-inch) Symptom Charts — Startup and Power Issues 21 2010-11-25
MagSafe Adapter – No Power
Unlikely cause:  LCD panel, logic board, fan, subwoofer, speakers, camera, microphone
Quick Check
SymptomsQuick Check
MagSafe Adapter – No Power
•
 
N
 o power to MagSafe 
connector
•
 
M
 agSafe connector status LED 
does not illuminate
•
 
N
 o power to portable 
computer without battery 1.
 V

erify power source. 
2.
 V

erify display is operating.
3.
 E

nsure MagSafe connector and...

LED Cinema Display (24-inch) Symptom Charts — Startup and Power Issues 22 2010-11-25
Sleep/Wake Issue
Unlikely cause:  LCD panel, fan, subwoofer, speakers, camera, microphone
Quick Check
SymptomsQuick Check
Sleep/Wake Issue
•
 
W
 on’t go to sleep or wake up 
from sleep 1.
 V

erify display is being used with supported 
system. 
2.
 U

se with known-good system.  If used as second 
display, check display preferences to see if display 
is recognized by system.
3.
 V

erify USB/display/power connectors are...

LED Cinema Display (24-inch) Symptom Charts — Startup and Power Issues 23 2010-11-25
5. Disconnect DC power cable from J0121 on logic board. 
Verify cable voltage at 
connector between Pin 1 
(24.5VDC) and Pin 3 (GND) is 
23.3–25.7 VDC. YesPower to logic board.  
Replace logic board.
M01
No
No power to logic board. 
Replace power supply. P01
6.
 V

erify all connections between 
logic board and LCD are secure. 
Visually inspect cables and 
connectors for any debris, 
damage, or bent pins. Yes
If...

LED Cinema Display (24-inch) Symptom Charts — Display Issues 24 2010-11-25
Display Issues
Blank / No Video, No Backlight
Unlikely cause:  power supply, fan, subwoofer, speakers, camera, microphone 
Quick Check
SymptomsQuick Check
Blank / No Video, No Backlight
•
 
N
 o video
•
 
N
 o backlight
•
 
D
 im backlight 1.
 V

erify display being used with supported system.
2.
 V

erify USB/display/power connectors are fully 
seated.
3.
 U

se with known-good system.  If used as second 
display, check display...

LED Cinema Display (24-inch) Symptom Charts — Display Issues 25 2010-11-25
4. Verify that the LCD function interface cable and LED driver 
cable connections are secure. 
See Functional Overview. Yes If connections are OK and 
secure and the display is still 
blank, go to step 5.
No
If cable is damaged,  
replace all-in-one cable or 
replace function cable. L14
5.
 S

hine bright (low heat) 
flashlight into the front of the 
LCD. Verify if an image is being 
displayed. Yes Image present but backlight 
is...

LED Cinema Display (24-inch) Symptom Charts — Display Issues 26 2010-11-25
2. Verify display’s USB hub and built-in camera are listed 
in the System Profiler’s USB 
device tree is not disappearing 
intermittently (refresh System 
Profiler to observe). Yes Power supply OK.  
Go to step 3.
No
Go to Dead Unit/No Power.
3.
 U

nplug and replug the 
Mini DisplayPort and USB 
connectors into a supported 
powered-up portable system 
and monitor the portable’s 
display. Verify that the 
portable’s display...

LED Cinema Display (24-inch) Symptom Charts — Display Issues 27 2010-11-25
LCD Image Issues
Quick Check
SymptomQuick Check
LCD Issues
•
 
P
 ixel anomalies
•
 
N
 on-uniform brightness
•
 
Inc
 orrect/missing colors
•
 
D
 istorted/blurred image
•
 
V
 ertical/horizontal lines 1.
 A

llow display to reach normal operating 
temperature for about 15 minutes before 
evaluating front-of-screen performance.
2.
 V

erify display being used with supported 
system. If used as second display, check display...

LED Cinema Display (24-inch) Symptom Charts — Display Issues 28 2010-11-25
Deep Dive: Pixel Anomalies
Unlikely cause:  logic board, power supply, fan, subwoofer, speakers, camera, microphone
CheckResult Action Code
1.
 D
 etermine if “defects” are dust/
debris on surface of glass panel 
or LCD panel.  Yes
Clean glass/LCD panel. 
Note:  If debris is inside LCD, it 
can’t be cleaned, therefore 
replace LCD panel.
No Go to step 2.
2. Determine if bright pixel  defects exceed the acceptable 
number. See...

LED Cinema Display (24-inch) Symptom Charts — Display Issues 29 2010-11-25
Deep Dive: Incorrect/Missing Colors
Unlikely cause:  power supply, fan, subwoofer, speakers, camera, microphone
CheckResult Action Code
1.
 V
 erify display’s USB hub and 
built-in camera are listed in the 
System Profiler’s USB device 
tree. Yes Power supply and USB 
communication OK.  
Go to step 2.
No
Go to USB Issues.
2.
 V

erify System Preferences: 
Displays: Color is using a valid 
display profile for this display. Yes If...

LED Cinema Display (24-inch) Symptom Charts — Display Issues 30 2010-11-25
Deep Dive: Distorted/Blurred Image
Unlikely cause:  power supply, fan, subwoofer, speakers, camera, microphone
CheckResult Action Code
1.
 V
 erify display’s Mini DisplayPort 
connector is plugged into 
known-good system. Yes Go to step 2.
No Connect Mini DisplayPort  cable to known-good system.
2.
 R

eseat Mini DisplayPort cable at 
system and display logic board. 
Determine if image corruption 
issue was resolved. Yes Loose...