Apple led cinema display 24inch User Manual

LED Cinema Display (24-inch) Basics — Serial Number Location 11 2010-11-25
Serial Number Location
Serial Number on Stand
The LED Cinema Display (24-inch)’s serial number is located on the base of the stand.  When 
replacing a stand, transfer the serial number to the new stand. 
Serial Number on Mechanism
The LED Cinema Display (24-inch)’s serial number is also located on the hinge mechanism 
inside, for users who remove the stand to use a VESA mount.  When replacing a mechanism, 
transfer the serial...

© 2008-2010 Apple Inc. All rights reserved.
 Apple Technician Guide 
Troubleshooting
LED Cinema Display (24-inch)   

LED Cinema Display (24-inch) Troubleshooting — General Troubleshooting 13 2010-11-25
General Troubleshooting
Troubleshooting Theory
For general information on troubleshooting theory, go to GSX and find the Service Training 
c ourse menu link. From there you can access the Troubleshooting Theory self-paced course.
Hardware vs. Software
For information on how to isolate a hardware issue from a software issue, refer to: 
kBase #TS1388: Isolating issues in Mac OS X
For information on how to troubleshoot a...

LED Cinema Display (24-inch) Troubleshooting — General Troubleshooting 14 2010-11-25
Functional Overview
A guide to possible symptoms as they relate to ports on the main logic board:
LCD Function Interface• No power to LCD
• No LED backlightDC In• No power
Camera• Not detected in USB Device Tree
• No green camera LED
• No camera video
Fan (1) & LCD (2) Temp Sensors• Fan runs fast if sensor is:     ° disconnected     ° connected to wrong location on MLB     ° not properly mounted or located     ° faulty...

LED Cinema Display (24-inch) Troubleshooting — General Troubleshooting 15 2010-11-25
Block Diagram
Refer to this diagram to see how modules are interrelated:  

LED Cinema Display (24-inch) Troubleshooting — General Troubleshooting 16 2010-11-25
Cable Routing Diagram  

LED Cinema Display (24-inch) Troubleshooting — General Troubleshooting 17 2010-11-25
Test Points Diagram
Refer to this diagram to see the location of test points and instructions for their use:
Below are main logic board test points that you can use 
to verify proper power flow in LED Cinema Display (24-inch). 
All voltages assume that the display is plugged into 
a power outlet, and NOT into the host computer (unless 
otherwise noted). 
• Turn the dial of your voltmeter/multimeter to measure 
DC (direct...

LED Cinema Display (24-inch) Symptom Charts — Startup and Power Issues 18 2010-11-25
Symptom Charts
Follow steps in the order indicated below. If an action resolves the issue, retest system to verify.
Note: A compilation of Quick Check tables is available at:
http://service.info.apple.com/QRS/en/quickreference.pdf
Startup and Power Issues
Dead Unit / No Power
Unlikely cause:  LCD panel, fan, subwoofer, speakers, camera, microphone
Quick Check
SymptomsQuick Check
Dead Unit / No Power
•
 
N
 o power
•
 
N...

LED Cinema Display (24-inch) Symptom Charts — Startup and Power Issues 19 2010-11-25
3. Remove LCD panel and disconnect LCD function 
interface cable. Verify voltage 
on logic board between test 
point TP11 (24.5VDC) and 
chassis ground (GND) is  
23.3–25.7 VDC. Yes 24.5VDC from power supply 
OK. Go to step 4.
No No power or incorrect power  at logic board. 
Go to step 6.
4. Verify voltage on logic board between test point TP61 
(3.3VDC) and chassis ground 
(GND) is 3.1–3.5 VDC. Yes 3.3VDC power on logic...

LED Cinema Display (24-inch) Symptom Charts — Startup and Power Issues 20 2010-11-25
9. Disconnect all connectors from the logic board EXCEPT the 
power supply cable.  
Verify voltages on logic 
board between test points 
TP61 (3.3VDC) and chassis 
ground (GND) is 3.1–3.5 VDC, 
and between TP13 (12VDC) 
and chassis ground (GND) is 
11.4–12.6 VDC. Yes Power supply OK. Suspect 
possible short, damaged 
connector, or faulty sensor/
fan/speaker. Reconnect 
connectors one at a time 
and retest for 3.3VDC at...