Apple studio display 15 lcd adc User Manual

							4 - Studio Display 15” LCD ( ADC)   Troubleshooting
Symptom Charts
Symptom Charts
How to Use the Symptom Charts
The Symptom Charts included in this chapter will help you diagnose specific symptoms related to the 
product. Because cures are listed on the charts in the order of most likely solution, try the cures in the 
order presented. Verify whether or not the product continues to exhibit the symptom. If the symptom 
persists, try the next cure. 
Note:  If you have replaced a module, reinstall the original module before you proceed to the next cure. 
						

							Studio Display 15” LCD ( ADC)  - 5
No Power Symptom Charts
No Power
1. Check J4 (see graphic below) input voltage. Do you measure +28V? I f yes, go on to the next step. If no, 
make sure the ADC (Apple Display Cable) cable is securely connected. Disconnect the display cable and 
check for bent pins on the display cable connector. Look for and carefully straighten any bent pins. Check 
for bent pins on the video card, straighten any bent pins. Also, verify that you have a known good video 
card in the computer. Turn on the computer to see if the symptom is gone.   
2. Check IC U5 (pin 4) voltage. U5 is located to the right and slightly up (about 1/2”) from connector J4. Do 
you measure +12V? If yes, go on to the next step. If no, replace the main board.
3. Check that the power button (touch switch) is working. Verify that the pins are not bent on the touch 
switch. Refer to Knowledgebase article 58813 to determine whether the touch switches have been 
software disabled. Reseat the connector at J9. If the power button touch switch is ok, go on to the next 
step. If you still have no power, replace the power button (touch switch).
4. If you still have no power, recheck the ADC cable for bent pins, verify the connections to the main board 
(J2, J4, J6).
5. Replace the main board.  
						

							6 - Studio Display 15” LCD ( ADC)   Troubleshooting
Symptom Charts
No Video
Dark Screen
1. Connect the display to a working computer. Shine a bright light onto the LCD to see if a faint image is 
visible. If the backlighting system is not functioning (and for some reason there is no diagnostic code 
on the LED) then the bright light should reveal a faint image of the desktop (or whatever is being 
displayed at the time). Do you see a faint image? If yes, replace the backlight bulb(s). If you don’t see a 
faint image, go on to the next step. Note:  A high intensity light generates heat which could damage the 
LCD display if left on for too long. Use caution to prevent damage to the LCD. 
2. Check J3 (on the main board), pins 1 and 2 for +12V. Do you measure +12V? If yes, go on to the next 
step. If no, replace the main board.
3. Check the inverter board connections. Reseat the connectors. If you still have no video, replace the 
inverter board.
4. Check the connections on the ADC cable and TMDS connector (cable that connects to the flat panel 
display). Reseat the connectors.
5. Check the connection on the main board cable at J2. This cable connects to the flat panel. Reseat the 
cables.
6. Replace the LCD display.  
						

							Studio Display 15” LCD ( ADC)  - 7
No Video Symptom Charts
Partially Dim Screen 
1. Plug the display into a known-good computer with a known-good video card and ADC display port. Boot 
the computer.
2. The Studio Display 15 will flash a repeating error code on the power LED if it detects a backlight fault. 
The error code consists of two short flashes followed by a long flash, a pause, and then the error 
repeats. When this error condition occurs, the problem could be bad bulbs, disconnected cable, or a bad 
inverter. Test the bulbs by pulling them out of the display and plugging them directly into the inverter. If 
they light, the bulbs are good. If they don’t light, try a known good bulb and try again. If the bulb still 
doesn’t light, replace the inverter. 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. 
						

							8 - Studio Display 15” LCD ( ADC)   Troubleshooting
Symptom Charts
Touch Switch Not Working
1. Check if the touch switch is disabled (refer to Kbase article 58813).
2. Check the ADC cable. Replace/repair the ADC cable. Check the video card and ADC connector for 
damage (bent pins).
3. Check the touch switches. The touch switches could be faulty (rare) or the touch switch cable(s) are 
disconnected. Check the cables and touch switch and replace as needed. Usually if only one touch 
switch is bad it’s probably the associated cable or touch switch. If neither touch switch works, it’s 
probably the ADC cable or the main board having USB problems.
4. The USB circuit on the main board might be faulty. Use the Apple System Profiler to determine if the 
display’s hub and the display are visible. If not, replace the main board. 
						

							Studio Display 15” LCD ( ADC)  - 9
USB Devices Connected to Display Hub Not Work-
USB Devices Connected to Display Hub Not Working
1. Test the USB ports. Connect another USB device to one of the display’s USB ports. Use the Apple 
System Profiler to determine if the display’s hub and the display are visible.
2. Does Apple System Profiler see the USB device you connected? If the hub shows up, but the attached 
USB devices don’t, check the USB cable and its connectors that attach to the main board. If the hub or 
attached devices don’t show up, there could be a problem with the ADC display cable (bent pins at the 
ADC connector). If the problem still exists, go on to the next step. 
3. Check connector J6 (on the main board). Make sure it’s connected and there are no bent pins.
4. Check Apple System Profiler again. Verify if the display’s USB hub is visible. If no, replace the main 
board or replace the Apple Display Cable. 
						

							10 - Studio Display 15” LCD ( ADC)   Troubleshoot-
Symptom Charts
Pixel Anomalies
Note: Refer to KnowledgeBase article 22194 for the most current Pixel Anomaly information and 
specifications. 
Article 22194 defines the term “pixel anomaly”, explains why such anomalies occur, and describes what to 
do if you feel your active matrix LCD panel has more than an acceptable number of pixel anomalies. 
						

							Studio Display 15” LCD ( ADC)  - 11
Pixel Anomalies Symptom Charts 
						

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Views
Apple Studio Display 15 LDC (ADC) 
						

							Apple Studio Display 15 LCD (ADC) Views
 
Exploded View
21
3
4
10
13 13
14
14
17
20
19
16
15
9
18
11
128
67
5
Foot Assembly
922-5621
Cover, Back
922-5623
Cover, Inner, Back
922-5624
Shield, EMI, LCD
922-5625
Hinge Assembly
922-5633
Chassis, Metal Frame
922-5628
Clip, Vertical
922-5631
Clip, Horizontal
922-5630 Cable Main, ADC
922-5635
Touch Switch
922-5636
922-5591, Rev.2
Display, LCD, 15
661-2780
Bezel, Front, 15
922-5590 Cover, Hinge
922-5622
Cover, USB Trim Ring
922-5627
Rear Panel Clip
922-5626
Clip, Horizontal
922-5630
Clip, Vertical
922-5631 Inverter Board
922-5632
Cover, Shield,
Backlight Bulbs
922-5592
Bulb, Upper
922-5644
Bulb, Lower
922-5645
Main Board
922-5629
922-5696, Rev.2
Bracket, Main Cradle
922-5634
Cable, 
Main B6-Adj Switch
922-5638
Cable, Main Board 
Power Switch
922-5637