Apple led cinema display 27inch User Manual
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LED Cinema Display (27-inch) Symptom Charts — Startup and Power Issues 21 2010-11-18 Sleep/Wake Issue Unlikely cause: LCD panel, fan, camera, speakers, subwoofer, microphone Quick Check SymptomsQuick Check Sleep/Wake Issue • Won’t go to sleep or won’t wake from sleep 1. Verify display is being used with supported system with up-to-date system software. 2. Verify USB/Mini DisplayPort/MagSafe connectors are fully seated. 3. Check brightness setting. 4. Use with known-good system. If used as second display, open Display Preferences (or press Option-F2) and check for presence of the middle Arrangement tab to confirm that display is recognized. Deep Dive Check ResultAction Code 1. Verify display’s USB hub and built-in camera are listed in the System Profiler’s USB device tree. Yes Internal USB buses active. Power supply appears OK. Go to step 3. No Go to step 2. 2. Unplug 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 DisplayPort connection from computer to LCD panel appears OK. Go to step 3. No Go to step 4. 3. Remove glass and LCD panel, reconnect MagSafe, DisplayPort and USB cables to a powered on computer. Set digital multimeter to DC and correct range and verify that a 23.3– 25.7 V DC voltage is present between logic board test point (24 V DC) and chassis ground (GND). Yes 24 V DC is available to logic board. Power supply appears OK. Go to step 5. No No power at logic board. Go to step 4.
LED Cinema Display (27-inch) Symptom Charts — Startup and Power Issues 22 2010-11-18 4. Verify if all connections between power supply, all- in-one cable, and logic board are secure. See Functional Overview. Yes If connections were secure, go to step 5. No Reseat connectors and retest. 5. Set digital multimeter to DC and correct range, and verify that a 11.4 -12.6 V DC voltage is present between logic board test point (12 V DC) and chassis ground (GND). Yes 12 V DC available to logic board. Replace logic board. M01 No No 12 V DC power from power supply. Replace power supply. P01 6. Visually inspect cables and connectors for any debris, damage, or bent pins. Reinstall LCD panel and verify if all connections between logic board and LCD panel are secure. Yes If connections are secure and display still does not function correctly, go to Blank / No Video, No Backlight. No Reseat connectors and retest. For damaged all-in-one cable, replace all-in-one cable. For other cable damage, replace affected cable. Uncategorized Symptoms Deep Dive Check ResultAction Code 1. Verify 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 (27-inch) Symptom Charts — Display Issues 23 2010-11-18 Display Issues Blank / No Video, No Backlight Unlikely cause: fan, camera, speakers, subwoofer, microphone Quick Check SymptomsQuick Check Blank / No Video, No Backlight • No video • No backlight • Dim backlight 1. Verify display is used with a supported system and up-to-date system software. 2. Verify USB/Mini DisplayPort/MagSafe connectors are fully seated. 3. Test display with a known-good system. 4. Connect display to a portable system, open System Preferences: Display (or press Alt-F2) and check for presence of the middle Arrangement tab to confirm that external display is recognized. 5. Open System Preferences: Displays and select Gather Display option to check for external display brightness setting. Deep Dive Check ResultAction Code 1. Connect display to AC power source. Connect Mini DisplayPort, MagSafe and USB connectors into a known- good, supported, powered-up portable. Verify display’s USB hub and built-in camera are listed in the System Profiler’s USB device tree. Yes Power is available to the display logic board, and USB communication working. Go to step 2. No Go to Dead Unit/No Power. 2. Unplug and replug 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 LCD is powered and detected by system. Go to step 7. No Suspected no power to LCD panel or no DisplayPort connection with system. Go to step 3.
LED Cinema Display (27-inch) Symptom Charts — Display Issues 24 2010-11-18 3. Remove glass and LCD panel screws, slightly pivot LCD panel and verify that the internal DisplayPort cable (part of all-in- one cable) and function cable are fully connected to LCD panel and logic board. Yes Go to step 4. No Reseat DisplayPort connection to LCD panel and/or function cable connections between logic board and LCD panel and retest. If issue persists go to step 4. For any damaged cable, replace affected cable before testing again: - all-in-one cable. - function cable. X03 X03 4. Unplug and replug 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 LCD is powered and detected by system. Go to step 7. No Suspect no power to LCD. Replace function cable and retest. If issue persists go to step 5. 5. Replace all-in-one cable and reinstall LCD. Unplug 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 LCD panel powered and detected by system. Go to step 7. No LCD panel still not detected by system. Suspect no LCD power from logic board. Go to step 6. 6. Replace logic board and reinstall LCD. Unplug 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 LCD panel powered and detected by system. Go to step 7. No LCD panel still not detected by system with replaced function cable, all-in-one cable and logic board. Suspect LCD panel video input damage. Replace LCD panel. L03 7. If the Blank/No Video/No Backlight issue persists, darken room and connect to a known- good supported system. Verify backlight is present by looking for faint glow from display. Yes LCD panel powered, detected by system and backlight is ON but there is no video on LCD. Replace LCD panel. L03 No LCD panel is detected by system but no backlight. Check whether video is present on LCD. Go to step 8.
LED Cinema Display (27-inch) Symptom Charts — Display Issues 25 2010-11-18 8. Shine bright (low heat) flashlight into the front of the LCD. and verify if any image is being displayed. Yes Video is present, so issue is only with missing backlight. Go to step 9. No No image displayed on LCD Replace LCD panel. L03 9. Remove glass and LCD panel screws, lift LCD panel to verify that the function cable, and LED backlight driver cable connections are secure. See Functional Overview. Yes If connections are OK and secure and there is still no backlight, go to step 10. No If any cable is damaged, replace affected cable and retest: - function cable - LED backlight driver cable (part of LCD panel) X03 L09 10. Remove LCD panel. Set digital multimeter to DC and correct range, and verify that a 23.3– 25.7 V DC voltage is present between logic board test point (24 V DC) and chassis ground (GND). Yes 24 V DC power for backlight is present on logic board, but no backlight. Suspect no V-sync signal coming to logic board. Go to step 11. No No 24 V DC present for LED backlight power. Replace power supply. P01 11. Replace function cable and retest. Verify that the no backlight issue is fixed. Yes Defective function cable prevented backlight from being enabled by logic board. X03 No Go to step 12. 12. Verify if the LED backlight driver cable (part of the LCD panel) has any signs of pinched or shorted wires. Also remove the logic board and verify if one or more of the three square inductors or adjacent components on top of board show signs of overheating. Yes LED backlight driver cable on LCD panel found damaged. Replace LCD panel, (make sure that you don’t pinch the LED driver cable from LCD panel) and retest. If the no backlight issue persists after LCD panel replacement, replace logic board (LED backlight output from logic board had been damaged by shorted cable.) L14 M25 No Suspect no LED backlight output from logic board: go to step 12. 13. Replace logic board and verify that the no backlight issue is fixed. Yes Defective logic board LED backlight driver output. M25 No Replace LCD panel. L09
LED Cinema Display (27-inch) Symptom Charts — Display Issues 26 2010-11-18 Noise / Unstable Flicker Unlikely cause: fan, camera, speakers, subwoofer, microphone Quick Check SymptomQuick Check Noise / Unstable Flicker • Image flickers • Audible noise 1. Verify display being used with supported system with all software updates installed. 2. Verify USB/Mini DisplayPort/MagSafe connectors are fully seated. 3. Use with known-good system. If used as second display, open System Preferences: Displays (or press Option-F2) and check for presence of the middle Arrangement tab to confirm that display is recognized. 4. Verify whether the issue also happens when System Preferences: Displays: Automatic Brightness checkbox is unchecked (If issue does not happen anymore when unchecked, jump to Unstable Brightness / Brightness Progressively Getting Low. 5. Adjust display brightness to all levels, and check for a correlation with noise/ backlight flicker issue. 6. (Noise) Check for correlation with fan operation on center of the back surface of display 7. (Noise) Play a sound from known-good source sound file and verify it does not cause any speaker distortion. Deep Dive Check ResultAction Code 1. Verify if noise/flickering is linked to a change of the video display or backlight level. Yes Suspected backlight or video related flickering issue. Go to step 2. No Noise does not appears to come from video or backlight circuitry but likely from audio or mechanical source. Go to Noise/Hum/Vibration.
LED Cinema Display (27-inch) Symptom Charts — Display Issues 27 2010-11-18 2. Verify in the System Profiler’s USB device tree that display’s USB hub and built-in camera are listed continuously and do not disappear intermittently (refresh System Profiler to observe). Yes Power supply appears OK. Go to step 3. No Go to Dead Unit/No Power. 3. Unplug and replug 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 noise/flickering, go to step 4. No Reseat connectors and retest. 4. Adjust Brightness level to low and high levels (with keyboard or System Preferences: Displays) and verify that noise/flicker issue varies acoordingly. Yes Issue is likely to be backlight- related. Go to step 8. No Go to step 5. 5. Remove glass and LCD panel screws, lift LCD panel and verify if 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 video is still unstable. Go to step 6. No Reseat connectors and retest. 6. Disconnect all-in-one cable and LCD function cable from logic board and system. Verify connectors and cable under magnification for pinched cables and damaged/bent pins. Yes If any cable is damaged, replace affected cable and retest: - all-in-one cable, - function cable. X03 X03 No Go to step 7. 7. If not already replaced, replace all-in-one cable, reconnect LCD panel and verify that video noise/flicker issue is fixed. Yes Issue was due to the all-in- one cable failure. No Replace LCD function cable. and retest. If flickering issue persists, go to step 8. 8. Check LED backlight driver cable and connectors and verify under magnification for pinched cable and damaged or bent pins. Yes Damaged LED backlight driver cable. Replace LCD panel. L14 No Go to step 9.
LED Cinema Display (27-inch) Symptom Charts — Display Issues 28 2010-11-18 9. Reconnect LCD panel and verify that video noise/flicker issue is appears at all backlight levels. Yes LED backlight output from logic board appears defective. Replace logic board. M25 No Go to step 10. 10. Reconnect LCD panel and verify that video noise/flicker issue only appears with low backlight levels. Yes Backlight power from power supply appears defective. Replace Power supply board. P04 No Review symptom occurrence to match with one of the last steps. Unstable Brightness / Brightness Progressively Getting Low Unlikely cause: fan, camera, speakers, subwoofer, microphone Quick Check Symptom Quick Check Unstable Brightness / Brightness Progressively Getting Low. • Brightness quickly or slowly varies • Brightness slowly decreases to a low level over time. 1. Verify display is used with a supported system and up-to-date system software. 2. Verify USB/Mini DisplayPort/MagSafe connectors are fully seated. 3. Use with known-good system. If used as second display, open Display Preferences (or press Option-F2) and adjust Brightness. 4. Verify whether issue disappears when the System Preferences: Displays: Automatic Brightness checkbox is unchecked (If issue still happens when unchecked, jump to Noise / Unstable Flicker. 5. Verify that issue does not depend on specific room lighting.
LED Cinema Display (27-inch) Symptom Charts — Display Issues 29 2010-11-18 Deep Dive CheckResultAction Code 1. Connect display to a known- good supported powered-up system with up-to-date system software. Check the Automatic Brightness Setting checkbox in System Preferences: Displays, Then cover camera with your hand and verify if brightness varies accordingly. Yes Ambient Light Sensor appears OK. Go to step 3. No No or Incorrect brightness variation to light change, ALS/ Camera connection need to be checked. Go to step 2. 2. Verfiy in System Profiler’s USB device tree that display’s USB hub and built-in camera are listed. Yes Ambient Light Sensor (located in camera assembly) appears OK. Go to step 3. No Check and reseat camera cable connections at logic board and camera. If connections are secure Replace camera cable and retest. If issue persists, replace camera and run EEPROM Reset Tool to calibrate new camera module (see camera take-apart section). X03 X03 3. Remove glass and LCD panel screws, lift LCD panel and verify connection of the LCD temp sensor (on back of LCD panel) is secure to LCD panel connector, and that sensor is covered with the insulating foam. Yes LCD temp sensor appears OK. Go to step 4. No Reseat LCD temp sensor cable, and readjust the insulating foam around sensor to protect it from internal ambient temperature. If LCD temp sensor cable is damaged, replace LCD temp sensor cable. X03 4. Check that fan connection to logic board is secure, remove all fan screws and pivot fan so you can see blades, then reconnect display to AC power and verify that fan is operating. Yes Fan is connected and operating. Go to step 5 No Reseat fan and retest. If fan still not running, go to Fan Failures/ Thermal Issue.
LED Cinema Display (27-inch) Symptom Charts — Display Issues 30 2010-11-18 5. Reinstall fan and LCD panel and retest. Verify that brightness level remains equal while display is warming up. YesDisplay brightness does not seem to suffer from the brightness adjustment circuitry. Go to Noise/ Unstable Flicker. No Fan connected and operating. but brightness still cannot be compensated over temperature increase. Replace LCD temp sensor cable. If issue (brightness still getting low after warmup) persists, replace LCD panel. X03 L07 LCD Image Issues Quick Check Symptom Quick Check LCD Issues • Pixel anomalies • Non-uniform brightness • Incorrect/missing colors • Distorted/blurred image • Vertical/horizontal lines • Display appears washed or with dominant color tint 1. Verify display being used with supported system with LED Cinema Display software installed. 2. If used as second display, check display preferences to see if the display’s native resolution is correctly recognized by system. 3. Verify USB/Mini DisplayPort/MagSafe connectors are fully seated. 4. Check System Preferences: Displays: Color for the selection of an incorrect custom display profile. 5. Check brightness setting. 6. In System Preferences: Displays, uncheck setting “Automatically adjust brightness as ambient light changes” 7. Clean glass panel while checking for dust/debris. Deep Dive: General Check ResultAction Code 1. Verify if issue is blank/no video. Yes Go to blank/no video, no backlight. No Go to step 2.