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当前版本: oldturkey03 ,

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I'd start by following Deep dive suggestions from Apple but would stop at #7
 
Deep Dive
 
1. Verify boot chime present and fans running when computer powered ON. (Reset SMC and clear PRAM if necessary for proper boot up.)
 
Yes Power on self test OK.
 
Go to step 2.
 
No Go to Won’t Start Up symptom flow.
 
2. Verify if image is visible on built-in LCD panel, with adjustable backlight level.
 
Yes Video present. Verify system functionality and return to user or go to appropriate troubleshooting flow.
 
No Go to step 3.
 
3. Connect supported external display. Verify if image appears on external display when system is booted.
 
Yes External display detected by system. Video circuitry on logic board functional.
 
Go to step 4.
 
No Go to No Video symptom flow.
 
4. Verify if LCD backlight is ON by looking for faint glow from display when viewed in darkened room with brightness set at maximum.
 
Yes LED backlight is functioning.
 
Go to step 7.
 
No Go to step 5.
 
5. Shine bright (low heat) flashlight onto front of LCD. With computer powered ON verify if a faint image is visible.
 
Yes LCD panel functional but backlight is missing or dim. Remove LCD panel and inspect and reseat the
 
following cable connections:
 
-Backlight power cable
 
between backlight board and LCD panel.
 
-Vertical sync cable between backlight board and LCD panel.
 
-DC power cable to backlight board and power supply.
 
Replace any damaged cable.
 
Reinstall LCD panel and go to step 6.
 
No No image or backlight.
 
Go to step 7.
 
6. Power ON system. Verify if image is now visible on LCD panel with correct backlight level.
 
Yes Issue resolved.
 
No Replace LED backlight board.
 
Retest. If issue persists, go to step 7.
 
7. Inspect and reseat internal DisplayPort cable (between logic board and LCD panel).
 
Power ON system. Verify if image is visible on built-in LCD display.
 
Yes Issue resolved.
 
No Replace internal DisplayPort cable.
 
If issue persists, replace LCD panel. Run Apple Service Display Utility to verify the resolution of intermittent display flickering symptoms. If the Apple Service Display Utility fails, contact Technical Service Provider Support
 
Anything after that, you'd have to measure some voltages on your logicboard.

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原帖由: oldturkey03 ,

文本:

I'd start by following Deep dive suggestions from Apple but would stop at #7

Deep Dive

1. Verify boot chime present and fans running when computer powered ON. (Reset SMC and clear PRAM if necessary for proper boot up.)

Yes Power on self test OK.

Go to step 2.

No Go to Won’t Start Up symptom flow.

2. Verify if image is visible on built-in LCD panel, with adjustable backlight level.

Yes Video present. Verify system functionality and return to user or go to appropriate troubleshooting flow.

No Go to step 3.

3. Connect supported external display. Verify if image appears on external display when system is booted.

Yes External display detected by system. Video circuitry on logic board functional.

Go to step 4.

No Go to No Video symptom flow.

4. Verify if LCD backlight is ON by looking for faint glow from display when viewed in darkened room with brightness set at maximum.

Yes LED backlight is functioning.

Go to step 7.

No Go to step 5.

5. Shine bright (low heat) flashlight onto front of LCD. With computer powered ON verify if a faint image is visible.

Yes LCD panel functional but backlight is missing or  dim. Remove LCD panel and inspect and reseat the

following cable connections:

-Backlight power cable

between backlight board and LCD panel.

-Vertical sync cable between backlight board and LCD panel.

-DC power cable to backlight board and power supply.

Replace any damaged cable.

Reinstall LCD panel and go to step 6.

No No image or backlight.

Go to step 7.

6. Power ON system. Verify if image is now visible on LCD panel with correct backlight level.

Yes Issue resolved.

No Replace LED backlight board.

Retest. If issue persists, go to step 7.

7. Inspect and reseat internal DisplayPort cable (between logic board and LCD panel).

Power ON system. Verify if image is visible on built-in LCD display.

Yes Issue resolved.

No Replace internal DisplayPort cable.

If issue persists, replace LCD panel. Run Apple Service Display Utility to verify the resolution of  intermittent display flickering symptoms. If the Apple Service Display Utility fails, contact Technical Service Provider Support

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