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 receptacle are 
clean.
4.
 V

erify LED glowing amber or green when 
MagSafe connector attached to compatible  
portable computer.
Deep Dive
Check Result Action Code
1.
 A
 ttach MagSafe cable to 
known-good compatible 
system. Verify connector status 
LED illuminates amber or 
green. Yes LED color illuminates amber 
or green depending on 
charging state. Go to step 4.
No Go to step 2.
2.
 V

isually inspect MagSafe cable 
and user’s portable MagSafe 
receptacle for physical damage, 
stuck pins, debris, or metal 
fragments.  Yes
See kBase #HT2315. 
Go to step 4.
No Go to step 3.
3.
 V

erify after unplugging and 
replugging the display’s AC 
power cord, the MagSafe 
connector LED color illuminates 
amber or green depending 
charging state. Yes Go to step 4.
No
Replace all-in-one cable. P15
4.
 V

erify a known-good 
compatible system operates, 
and charges a discharged 
battery to 100% simultaneously 
from MagSafe cable. Yes Repair complete.
No
Replace power supply.  
If needed afterwards, refer to 
Dead Unit/No Power. P01  
						

							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 fully 
seated.
4.
 C

heck brightness setting.
Deep Dive
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 OK.  
Go to step 3.
No Go to step 2.
2. Verify voltage on logic  board between J0121 Pin 1 
(24.5VDC) and Pin 3 (GND) is 
23.3–25.7 VDC. Yes Power supply OK.  
Go to step 3.
No No power at logic board.   Go to step 4.
3.
 U

nplug and replug the Mini 
DisplayPort connector into 
a supported powered-up 
portable system and monitor 
the portable’s display. Verify 
that the portable’s display 
briefly turns off then back on. Yes Logic board OK.  
Go to step 6.
No Go to step 4.
4. Verify all connections between  power supply, all-in-one cable, 
and logic board are secure. See 
Functional Overview. Yes If connections are secure and 
display still does not function 
correctly, go to step 5.
No Reseat connectors and retest.  
						

							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 connections are secure and 
display still does not function 
correctly, go to Blank/No 
Video.
No
Reseat connectors and retest. 
For damaged AIO cable, 
replace all-in-one cable. X04
Uncategorized Symptoms
Check
Result Action Code
1.
 V
 erify whether existing 
symptom code applies to the 
issue reported by the user. Yes Jump to appropriate 
symptom code flow.
No
Document reported failure 
and send feedback to 
[email protected] 
stating that a suitable 
symptom code wasn’t found. N99  
						

							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 preferences to see if display 
is recognized by system.
4.
 C

heck brightness setting.
Deep Dive
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 3.
No Go to step 2.
2.
 U

nplug and replug the Mini 
DisplayPort connector into 
a known-good, supported, 
powered-up portable system 
and monitor the portable’s 
display. Verify that the 
portable’s display briefly turns 
off then back on. Yes Display detected by system. 
Go to step 3.
No
Go to Dead Unit/No Power.
3.
 D

arken room and connect to a 
known-good supported system.  
Verify backlight by looking for 
faint glow from display. Yes Video signal from host system 
OK. Backlight ON. 
Go to step 5.
No Go to step 4.  
						

							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 not ON. Go to step 6.
No
Replace LCD panel. L03
6. Verify voltage on logic board 
between test point TP81 
(24.5VDC) and chassis ground 
(GND) is 23.3–25.7 VDC. YesLED backlight power present. 
Replace LCD panel.
L03
No
Poor or no LED backlight 
power at logic board.  
Replace logic board. L07
Noise / Unstable Flicker
Unlikely cause:  fan, subwoofer, speakers, camera, microphone
Quick Check
Symptom
Quick Check
Noise / Unstable Flicker
•
 
Image flick
 er
•
 
A
 udible noise 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 preferences to see if display 
is recognized by system.
4.
 V

erify known-good source sound file not causing 
speaker distortion.
Deep Dive
Check Result Action Code
1.
 V
 erify if issue is due to video 
flickering coming from display. Yes Suspected flickering issue. 
Go to step 2.
No Audible noise issue.   Go to step 8  
						

							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 briefly turns 
off then back on. Yes If connections are secure and 
display still shows unstable 
flickering, go to step 4.
No Reseat connectors and retest. 
4. Verify all connections between  power supply, all-in-one cable, 
LCD, and logic board are secure. 
See Functional Overview. Yes If connections are secure and 
the display is still unstable 
flickering, go to step 5.
No Reseat connectors and retest. 
5.
 D

isconnect all-in-one cable 
and LCD function interface 
cable from logic board and 
system. Verify connectors and 
cable under magnification for 
pinched cables and damaged/
bent pins.  Yes
If cable is damaged,  
replace all-in-one cable or 
replace LCD function 
interface cable.
L14
No Go to step 6.
6.
 D

isconnect LED driver cable 
from logic board. Verify 
connectors and cable under 
magnification for pinched cable 
and damaged or bent pins.  Yes
Damaged LED driver cable. 
Replace LCD panel.
L14
No Go to step 7.
7.
 S

hine bright (low heat) 
flashlight into the front of the 
LCD. Verify if an image is being 
displayed during flickering. Yes
Image present but backlight 
is flickering.  
Replace logic board.
L06
No
Replace LCD panel. L06
8.
 V

erify the source of the noise 
is the electrical as opposed to 
mechanical Yes Noises that are not audible 
from the normal user position 
are considered acceptable.
No
Noise from another source. 
Go to Noise, Hum, Vibration.  
						

							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 
preferences to see if display is recognized by 
system.
3.
 V

erify USB/display/power connectors are fully 
seated.
4.
 C

heck display preferences for use of custom 
display profile.
5.
 C

heck brightness setting.
6.
 C

lean glass panel while checking for dust/debris.
Deep Dive: General
CheckResult Action Code
1.
 V
 erify if issue is blank/no video. Yes
Go to blank/no video.
No Go to step 2.
2.
 V

erify if issue is bright or dark 
dot pixel anomalies. Yes
Go to pixel anomalies.
No Go to step 3.
3.
 V

erify if issue is non-uniform 
brightness. Yes
Go to non-uniform 
brightness.
No Go to step 4.
4.
 V

erify if issue is incorrect/
missing colors.  Yes
Go to incorrect/missing 
colors.
No Go to step 5.
5.
 V

erify if issue is distorted/
blurred image.  Yes
Go to distorted/blurred 
image.
No Go to step 6.
6.
 V

erify if issue is vertical or 
horizontal lines. Yes
Go to vert/horiz lines.
No LCD functioning OK.  
						

							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 kBase #HT1721 YesReplace LCD panel.
L08
No LCD meets bright pixel defect  specifications. Go to step 3.
3. Determine if dark pixel defects exceed the acceptable 
number. See kBase #HT1721 YesReplace LCD panel.
L08
No LCD meets dark pixel defect  specifications. Go to step 3.
4. Determine if the combination of bright/dark pixel defects 
exceed the acceptable 
number. See kBase #HT1721 YesReplace LCD panel.
L08
No Explain to user that LCD is  within specifications for pixel 
defects. Do not replace LCD.
Deep Dive: Non-Uniform Brightness
Unlikely cause:  logic board, power supply, fan, subwoofer, speakers, camera, microphone
Check Result Action Code
1.
 D
 etermine if brightness 
uniformity issue is visible after 
display has warmed up for 
approximately 15 minutes. Yes Go to step 2.
No Display backlight can take  several minutes to stabilize. 
2.
 D

isplay user-provided 
examples showing brightness 
uniformity issue. Determine if 
issue appears excessive when 
compared to a similar unit. Yes Go to step 3.
No Explain to user that  LCD appears to meet 
specifications.
3.
 R

emove front bezel and 
loosen screws securing LCD. 
Determine if brightness 
uniformity improves. Yes Inspect for mechanical 
interference with screws/
chassis/wires making contact 
with back of LCD. Retest
No
Replace LCD panel. L07  
						

							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 display profile is valid and 
the colors are still incorrect or 
missing, go to step 3.
No Calibrate display by creating a  manual profile using calibrate 
feature in System Preferences: 
Displays: Color. Retest.
3.
 V

erify that the glass panel and 
LCD are free of contaminants. Yes Go to step 4.
No
Clean glass/LCD panel. 
Retest.
4. Verify all connections between,  all-in-one cable, LCD, and 
logic board are secure. See 
Functional Overview. Yes Go to step 5.
No Reseat connections, replace  damaged cable(s) as needed. 
Retest.
5.
 S

et desktop pattern in System 
Preferences to “solid gray light.” 
Verify if incorrect/missing color 
issue affects entire display. Yes
Suspect poor video 
connection.  
Replace all-in-one cable.
L14
No Go to step 6.
6.
 S

et up user’s display side-by-
side with a known-good display 
showing the same image. Verify 
if issue is noticeably worse on 
the display being tested.  Yes
Replace LCD panel.
L02
No Small variations in color  uniformity are normal and do 
not warrant replacement or 
repair of the display.  
						

							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 cable.  Issue resolved.
No Go to step 3.
3.
 D

isconnect Mini DisplayPort 
cable from system and display 
logic board. Inspect connectors 
and cable under magnification 
for pinched cables and 
damaged/bent pins.  Yes
Replace all-in-one cable.
X04
No
Replace LCD panel. L04
Deep Dive: Vertical/Horizontal Lines
Unlikely cause:  logic board, power supply, fan, subwoofer, speakers, camera, microphone
Check Result 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 3.
No Go to step 2.
2.
 U

nplug and replug the Mini 
DisplayPort connector into 
a supported powered-up 
portable system and monitor 
the portable’s display. Verify 
that the portable’s display 
briefly turns off then back on. Yes Logic board OK.  
Go to step 3.
No Go to step 3.
3.
 V

erify all-in-one cable, and all 
connections between logic 
board and LCD are secure. 
Visually inspect cables and 
connectors for any debris, 
damage, or bent pins. Yes
If connections are secure 
and the display still does not 
function correctly, 
replace LCD panel.
L05
No
Connector/cable damage.  
Go to Mechanical Physical 
Damages.