MacBook Pro 13" Unibody Mid 2009

Mid 2009 Model A1278 / 2.26 or 2.53 GHz Core 2 Duo processor EMC 2326

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LCD doesn't light up after replacement, neither does Apple Logo

Hi everyone. this is my second time posting on iFix it.

I bought a Mid 2009 MacBook Pro off of Craigslist and the guy included a new lcd with it. However after I replaced the LCD, all it shows is a black screen. I connected it to an Apple Cinema Display and everything works flawlessly I can use it like a normal computer. However the display remains black. Was this a bad LCD? I already checked the connections...Do I need an inverter? Also the Apple logo on the top shell does not light up at all either. So I am not sure if I did something right, help would be appreciated very much, this is depressing in a way.

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Jabran, give us the last three digits of your serial number. this will help us to identify your computer properly. Right now it appears as if your computer does not have an inverter. The display is a LED backlight LCD display and does not utilize an inverter but an LED driver on the board.

by oldturkey03

Last three digits are 66H, sorry I didn't respond sooner, my BlackBerry notified me now...I appreciate the help, if you can let me know what the problem is it will save me a trip to the Apple Store, I was going to ask them to take a look at it and let me know what is EXACTLY wrong with it. That way I can perform the repair my self.

by Jabran

looks like these could be your specs: Intro Date: June 8, 2009 Disc Date: April 13, 2010 Order No: MB990LL/A Model No: A1278 (EMC 2326*) Subfamily: Mid-2009 13" Model ID: MacBookPro5,5 Std RAM: 2 GB Std VRAM: 256 MB Std Storage: 160 GB (5400 RPM) Std Optical: 8X DL "SuperDrive"

by oldturkey03

I also forgot to mention that the brightness keys do not work, they do not respond at all, is that an issue with this also? I already tried to reset the SMC and PRAM, nothing happened, and how hard is it to replace the WLED driver? Would someone on here be able to do it for me? I'd be willing to pay because I know Apple would charge an outrageous price.

by Jabran

Might it be possible that the LCD cable got caught in the casing? Or the cable shorted out? Cause I mean, this was a brand new monitor the guy gave me still sealed in plastic and bubble wrap...

by Jabran

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2 Answers

Jabran, your model does not have an inverter. It utilizes a WLED driver on the logic board. There is a fuse that one can check as well. This is a bit of a PITA and could be tough. Let us know how advanced you want to go with this. Anyhow, lets try the things that Apple suggest first. Here is the quick check for your computers symptoms:"

Symptom Quick Check

Power, but No Video

• Power

• No video

• fan, hard drive spin, or optical drive reset sound

• sleep LED is on or went on

• light if Caps Lock pressed

1. Reset SMC.

2. Reset PRAM.

3. If no startup chime, verify with known-good memory.

4. Verify with external monitor.

5. Press Option key on startup.

Here is the deep dive for that:"

Check Result Action Code

1. Characterize video issue Define whether the issue is a bad image with backlight OR no video issue. Verify whether some image even distorted is visible.


Bad image quality,go to step 5.


No image seen or no backlight, go to step 2.

2. Isolate peripherals as cause:

disconnect all peripherals,external devices, Express Card and display adapters if present and verify that video is displayed.

Yes Suspect peripherals as cause. Reconnect one at a time, verifying unit operation at each stage.

No Go to step 3.

3. Adjust Brightness

Power-on unit , attempt to adjust brightness to maximum using brightness (F1/F2) keys and verify that video is displayed.

Yes Video displayed - Brightness set to minimum, panel backlight was inadvertently turned off. If backlight returns to low check for stuck F1 key on keyboard.

No Go to step 4.

4. Reset SMC and verify that system video is displayed.

Yes Corrupt SMC state preventing video.

No Go to step 5.

5. Reset PRAM. If no action, use external keyboard with same sequence. Verify that system video is displayed.

Yes Invalid or corrupt PRAM contents affecting video output.

No Go to step 6.

6. Connect external video: Connect known-good VGA/ DVI adapter to known-good display, press power button and close display to force main screen startup on external video. Verify that video is correct when displayed from external display.

Yes Video correct on external display. Research available firmware and software updates, retest. If returning with software already updated, go to step 7.

No Replace logic board with according symptom code:-no video -bad/distorted video

7. Isolate LCD display detection:

Disconnect external monitor and reopen display and restart unit. Verify that sleep LED indicator goes off after internal LCD has been detected.

Yes Sleep LED goes off when LCD detected.

-If still no video then Go to step 8,

-If video present, but with defect, go to step 9.

No Internal LCD not detected. Run Clamshell Service Diagnostic utility and check for LCD panel presence. If not found, reseat LVDS cable connection on logic board and retest. If sleep LED does not go off after cable is reseated, go to step 10.

8. Check for sleep sensor condition. If display assembly sleep sensor is stuck in a closed state, video will appear on internal display temporarily,until the OS sleeps the system.Disconnect BIL/ sleep cable and restart unit without external display. Verify that system starts up with video on internal display stays on and does not go into sleep mode.

Yes Sleep sensor was stuck or had shorted cable. Replace BIL/sleep sensor cable.

No Symptoms unchanged.

Go to step 9.

9. Check for No Backlight. Power on unit. Using a lamp or bright light source, verify that a faint image or Apple logo appears.

Yes Logo image visible - check LVDS cable. Inspect cables fordamage near clutches:

- if damaged, replace display assembly and go to step 11

- if cable is not damaged, run Clamshell Service Diagnostic utility and check for LCD panel presence. If not found, reseat cable and retest, then go to step 11.

No If symptom continues,go to step 10.

10. Verify with Known good display assembly Connect known-good display assembly to system.

Yes System is functioning with known-good display assembly Replace display assembly if following symptom reporting:

- had no power issue

- had incorrect/missing colors

- had blank video

- had distorted / blurred video

- had vertical/horizontal lines

- had noise/unstable flickering

- had dim backlight

- had bad spot(s)/pixels

- had no backlight

- could not change resolution

No Symptoms unchanged - replace logic board.

11. Verify with reseated LVDS cable or replaced display assembly Verify that unit now has video and backlight.

Yes Issue was only due to damaged display assembly or unseated cable.

No Display cable damaged the logic board. Replace logic board.

The only thing I'd skip for now is the replacement of the logic board. Let us know what happened. Hope this helps, good luck


Here is a picture of the fuse and WLED driver location

Block Image

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Hi OldTurkey03. Many thanks for this wonderful flowchart for diagnosing video issues on this one. I used your flowchart to determine my issue with video.

Mine is a Macbook 13 2009, white unibody. Mine is a problem caused by a mishap. the macbook started up fine and booted good. i saw video and everything was great. then i opened the bottom cover, removed battery connector and installed a new hard drive. connected it to the data cable but forgot to put back locking bar of the hard disk. I turned the system on, everything worked good. then !@#$ broke loose when i raised the front of the laptop. the hard disk came off and slid on the logicboad towards the video connector. the computer shorted and turned off. When i turned it back on, i lost video almost completely.

The laptop now chimes, starts good, boots up. I can see the laptop boots up successfully because i can see the video on the black screen. i can see the Mac OSX 10.6 Interface. But that is all. i am also able to see the video in an external monitor using a Thunderbolt connector on the VGA port. So, almost all is well with the logicboard, except i fear i may have blown "the fuse" because this one too must use a WLED driver becacuse there is no inverter connection to the logicboard. I have also tried to reset PRAM NVRAM and did not help.

Any idea what i can do to revive my Macbook Unibody whte?

One more thing, my logicboard is slightly different in ergonomics to the picture you posted up there. the VGA interface connector is located at the corer and is about 45 degrees to the corner, as opposed to yours running parallel to the RHS of the board, or at 90 degrees to the front side.

Here is an iFixit link to the VGA port Interface and possible location of the fuse and driver chip.

Please help.


by the way, i also replaced the display with one from another working macbook. Sysmptoms are still the same.

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Jabran will be eternally grateful.

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