|Jul 20, 2010, 04:21 PM||#1|
MacBook Pro Unibody - No Backlight - Logic Board Question
IMPORTANT NOTE: Further in this thread you will read that this part is a high frequency capacitor. IT IS NOT A FUSE!!! PLEASE do not go about replacing this part with anything other than a capacitor. READ CAREFULLY the whole thread before messing around with component substitutions.
I obtained a Macbook Pro 13 unibody with non functioning display (everything else works). I took it apart ad discovered that the LVDS cable end was completely destroyed. I ordered a replacement display assembly (complete with LVDS cable). I now have an image but no backlight.
Upon close examination of the components surrounding the LVDS connector I notice I have a component missing compared to a detailed photo of the same motherboard that I found on the net. I am not sure if this component might be a fuse that has been removed. I am trying to find someone who has one of these logic boards accessable that can identify what this part is supposed to be.
Update: There are many many more tips and info in this thread to help you with troubleshooting backlight issues on Macbook Unibody.
In particular the WLED driver should be checked for failure. A useful method is to test the resistance (impedance) from each pin of the WLED driver device to ground. Typical values are shown below.
Make sure power is removed from board before testing resistance. Unplug battery or battery connector.
Macbook Pro 13"
Device LP8543 Pin 1 is lower left and counts counter clockwise around the device.
Pin Resistance to ground
6 >1M not connected
10 not connected
19 not connected
On Macbook 13 unibody aluminum non-Pro
If your WLED driver is blown you may measure zero or low resistance on some of the pins that are not supposed to be ground.
Last edited by Dadioh; Sep 20, 2012 at 08:34 PM.
|Jul 20, 2010, 05:03 PM||#4|
You would have to be a moron to not realize that taking apart the entire computer voids the warranty. The only thing that doesnít is upgrading the HDD and ram.
so Iím wondering why he still did it.
|Jul 20, 2010, 05:38 PM||#5|
I am looking for the help of someone that knows the right end of a multimeter to measure the component in question and tell me what the value is. Maybe this is the wrong forum given the "moron" accusation. Considering I am an experience electrical engineer with design background I would guess the accusation is just a "little" off base. Maybe I will try the question in a forum of like-minded repair oriented people.
|Jul 20, 2010, 05:39 PM||#6|
|Jul 20, 2010, 05:50 PM||#7|
I apologize if I pissed you off. You might want to check ifixit.com. Im afraid I cannot be of much assistance (as you may have already assumed).
|Jul 20, 2010, 06:01 PM||#8|
I may end up buying another as-is MBP just to add to my inventory of parts and provide the answer to my own question. However, if there is another hobbyist out there that has one of these boards at the ready they could take a 20 second multimeter measurement for me. Here's hoping.
|Aug 2, 2010, 08:55 PM||#12|
You will need some electronics skills and a good multimeter to sort through this I expect.
|Sep 5, 2010, 11:24 AM||#13|
I can send you a schematic of MacBook pro 15" unibody Late 2008, if that would help you out?
On my board all white components are fuses.
Last edited by jankro; Sep 5, 2010 at 03:05 PM.
|Sep 5, 2010, 12:10 PM||#14|
|Sep 5, 2010, 02:03 PM||#15|
Give me a e-mail address that can accept a 2.5Mb attachment and I'll sen it to you right away.
Actually, since I could not find private message function from this board, I put it up at 2shared and here is the link:
I added a short instruction about the BoardView application.
Last edited by jankro; Sep 5, 2010 at 03:06 PM.
|Sep 5, 2010, 11:28 PM||#16|
|Sep 30, 2010, 02:55 PM||#17|
no backlight on macbook pro 15 unibody
OK for all the people with no backlight on a macbook pro 15" unibody.
first of all thanks to the man with the schematic....
I take it you have checked the flurecent and inverter allready and both are ok.
on the logic board there is a fuse that supply's the voltage/ currant to the backlight circuit...its F9800.Its located on the board near the botom of the left fan on the component side of the board.(same side that has the cpu and gpu on it).
the fuse is a smd and its white with just a dot on it.get your multimeter and if its open circuit thats you problem.
got mine fixed today...
If you need a hand then drop me a line and i will try to see what i can do...
Had to share this as it took me a good day to put right,,,
|Sep 30, 2010, 04:31 PM||#18|
are you sure it's not stolen? with my undercover anti-theft i can make it fake a hardware failure with the screen not turning on.
so when it's taken to an authorized apple center, they can tell it's been stolen.
MacBook Pro 15" 512gb SSD + iPad 3 white + iPad 3 black + iPhone 5 black
|Sep 30, 2010, 06:42 PM||#19|
|Sep 30, 2010, 06:44 PM||#20|
I can see how it would be possible for a SW program to tell the WLED driver not to enable since that is exactly what can be done with the F1 and F2 keys on the keyboard.
|Sep 30, 2010, 10:15 PM||#22|
|Oct 4, 2010, 06:20 PM||#23|
where do you people come from? you just bust out and "blah blah"
Last edited by lPHONE; Oct 4, 2010 at 06:29 PM.
|Oct 7, 2010, 09:29 PM||#24|
i have a similar problem,
i have a Macbook A1181 13 2.0GHz with a non working monitor,
after power-on i get a half second flash light from the lcd and from the led light web-camera
and i cant see any image at all (no faint images or back light) from the monitor
i already replace the inverter, still the same symptoms
i think it is the logic board
after make some tests with a voltimeter on the cable from logic board that goes on inverter i can see the same symptoms on the voltimeter (the voltage go high for half a second)
i donīt have a video rgb cable to hook the computer to a external monitor
here my targets:
- it is a bad inverter cable?
- it is a bad logic board?
- it is a smd fuse on logic board?
- it is a Missing enable voltage from motherboard's video chip?
My last option is to replace the logic board
but before i want to try to fix my self
tanks every one
|Oct 8, 2010, 06:01 PM||#25|
No backlight MB13 unibody
I have been aiming my efforts at the QFN package also until I came upon this thread. I have a fuse (closed) on the MB but it's not as small as described above. Can you give me a description of where about on the MB you found the tiny fuse. I'm at my macbook for at least two weeks now with no luck. Tks.
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