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MacBook Pro Unibody - No Backlight - Logic Board Question

Perhaps someone here can provide some assistance.

I've got a A1286 Late 2008 MBP 15" that has backlight issues. They are somewhat unique because it will work on and off and respond to movement. External monitor works fine. When the backlight goes out I can get it to come back on by holding the sides of the laptop while open and 'twisting' the left side forward and the right side back ward. This combination of pressure will make the screen come back on, 'twisting' in the reverse direction will make it shut off.

The laptop was dropped on its spine hard enough to bend the hinges slightly (still opened and shut without issue) about 2yrs ago (backlight issues have been going on for about 6 months). I did have a bloated battery for some time that eventually got to the point of pressing the mouse button from the inside. I think the issues may have started on replacing the battery but I'm not certain.

I've since replaced the hinges, checked the connections, and looked under the clutch cover for anything amiss. The torque required during the 'twisting' has increased and the backlight sometimes will not stay on unless pressure is applied.

I am thinking that maybe some small component joint has broken on the logic board and needs to be resoldered / held down with something but don't know where to look.

Thanks for any and all help. :D
 
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wickawack said:
Perhaps someone here can provide some assistance.

I've got a A1286 Late 2008 MBP 15" that has backlight issues. They are somewhat unique because it will work on and off and respond to movement. External monitor works fine. When the backlight goes out I can get it to come back on by holding the sides of the laptop while open and 'twisting' the left side forward and the right side back ward. This combination of pressure will make the screen come back on, 'twisting' in the reverse direction will make it shut off.

The laptop was dropped on its spine hard enough to bend the hinges slightly (still opened and shut without issue) about 2yrs ago (backlight issues have been going on for about 6 months). I did have a bloated battery for some time that eventually got to the point of pressing the mouse button from the inside. I think the issues may have started on replacing the battery but I'm not certain.

I've since replaced the hinges, checked the connections, and looked under the clutch cover for anything amiss. The torque required during the 'twisting' has increased and the backlight sometimes will not stay on unless pressure is applied.

I am thinking that maybe some small component joint has broken on the logic board and needs to be resoldered / held down with something but don't know where to look.

Thanks for any and all help. :D
Click to expand...

Could also be the LVDS cable. Any chance of trying a known good display?

If not, here is an experiment. With power removed and battery removed and Macbook bottom cover removed and battery compartment facing you. The right hand hinge is where the LVDS cable enters the display hinge. There is a small bracket to hold the LVDS cable in place. Remove the bracket.

Replace the battery. Place the Macbook on it's side, the side with the optical drive. Now boot the Macbook. Gently try moving the LVDS cable a bit to see if you can reproduce the intermittent backlight. Be very careful that you do not apply enough force to the cable to make it want to pop off the logic board connector. Disconnecting that with power on would not be good. But if wiggling the LVDS cable can cause the issue then I would say it is not the logic board but rather the cable.

Worth a shot to help troubleshoot the source anyway.

Good Luck.
 
Dadioh said:
Could also be the LVDS cable. Any chance of trying a known good display?

If not, here is an experiment. With power removed and battery removed and Macbook bottom cover removed and battery compartment facing you. The right hand hinge is where the LVDS cable enters the display hinge. There is a small bracket to hold the LVDS cable in place. Remove the bracket.

Replace the battery. Place the Macbook on it's side, the side with the optical drive. Now boot the Macbook. Gently try moving the LVDS cable a bit to see if you can reproduce the intermittent backlight. Be very careful that you do not apply enough force to the cable to make it want to pop off the logic board connector. Disconnecting that with power on would not be good. But if wiggling the LVDS cable can cause the issue then I would say it is not the logic board but rather the cable.

Worth a shot to help troubleshoot the source anyway.

Good Luck.
Click to expand...

First off, thanks for getting back to me so quickly. Funny you mention this. Laptop was already on it its side with the back off and the battery taped in. I removed the bracket and the problem seems independent of LVDS cable wiggling. I've already removed the clutch cover (plastic thing covering the guts of the hinge) and checked that there was no place where the fabric cable cover had been worn through.

I've linked a video of the issue at the end of this post. This was done without the back on, so the problem is independent of the back cover being on or off. As can be seen, sometimes it stays in the 'on state' and sometimes it stays in the 'off state.' Any ideas? Is it more likely to be a short or a break in a solder joint?

Also, I'm sure flexing the case like that isn't a good idea but when the backlight turns off, it is the only way to get it back on, albeit temporarily. I pretty much only use it with an external monitor, but finally decided to do some investigating.

Video of backlight turning on and off with force.
 
l.a.rossmann said:
Please don't do that.

I love freedom of information. I really do. I think it's an amazing thing in the 201*s that the internet has evolved past advertising, games, and porn. However, the amount of boards I've gotten to work on where someone has read this thread and put a solder blob over their fuse with burnmarks everywhere is tripled from what it was nine months ago, which has set my cynicism at record highs.

Buy a fuse. Replace the fuse. It's a 28 cent investment to not fry a $450+ board. It is worth it.
Click to expand...

Hi l.a. rossmann as previous posts I did replace the fuse recommended and located by dadiloh. I still get no backlight but I can see images on the screen using a flashlight and using an external MDP. So now it looks like the QFN WLED driver needs to be replaced. However I cannot located the WLED driver on the logic board. I don't have schematics nor do I know the part number. I would appreciate any help. My client needs his system back. The board number is 820-2914-a EMC.: 2421
 
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elitetek said:
Hi l.a. rossmann as previous posts I did replace the fuse recommended and located by dadiloh. I still get no backlight but I can see images on the screen using a flashlight and using an external MDP. So now it looks like the QFN WLED driver needs to be replaced. However I cannot located the WLED driver on the logic board. I don't have schematics nor do I know the part number. I would appreciate any help. My client needs his system back. The board number is 820-2914-a EMC.: 2421
Click to expand...

Just out of curiosity have you tried checking your LVDS connector to make sure there's no damage done to it? Inserting the LVDS cable and removing it over and over again really stresses the connector out big time. I had to learn this the hard way.

I have a 15" MBP late 2008 A1286 which has the same problem as you but I know for sure I have to replace the fuse and also replace the LVDS connector.
 
I just received a liquid spill macbook pro A1278 EMC 2419. It has the i5 processor. The mag safe stays green and does not charge. Even the battery status does not show blinking status. I removed the board and cleaned it. I also did an OHM check where most the liquid was spilled and found some possible problems. Now would there be a fuse which would need to be checked or a QFN chip that controls the charging.
2dtrl11.jpg
 
elitetek said:
Hi l.a. rossmann as previous posts I did replace the fuse recommended and located by dadiloh. I still get no backlight but I can see images on the screen using a flashlight and using an external MDP. So now it looks like the QFN WLED driver needs to be replaced. However I cannot located the WLED driver on the logic board. I don't have schematics nor do I know the part number. I would appreciate any help. My client needs his system back. The board number is 820-2914-a EMC.: 2421
Click to expand...

So you're fixing these MacBooks for your clients?
 
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No Backlight - MBP 15" 2009 Logic Board 820-2533-B

Hi all,

Finally got some pictures... This is a MBP 15" 2009 logic board 820-2533-B. Also learned its not easy to get macro shots..! Hope these work.

I'm essentially trying to locate the fuse and the WLED, but as you'll notice the LVDS connection (I-PEX) may also have some issues... If someone could point out these parts I'll grab the multimeter.

And the TDK chip,... believe it or not a pencil fell on the board and chipped the corner - it hasn't appeared to affect anything, still the same issue, no backlight, everything else runs well via ext monitor and/or with a flashlight on LCD screen.

Many many thanks!!
 

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willko said:
Hi all,

Finally got some pictures... This is a MBP 15" 2009 logic board 820-2533-B. Also learned its not easy to get macro shots..! Hope these work.

I'm essentially trying to locate the fuse and the WLED, but as you'll notice the LVDS connection (I-PEX) may also have some issues... If someone could point out these parts I'll grab the multimeter.

And the TDK chip,... believe it or not a pencil fell on the board and chipped the corner - it hasn't appeared to affect anything, still the same issue, no backlight, everything else runs well via ext monitor and/or with a flashlight on LCD screen.

Many many thanks!!
Click to expand...

Here you go
 

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macbook pro unibody 2011 no backlight

Hi all,
I enjoy reading this forum, specially we have Dadioh help with his expertise and dedication. I have my macbook pro early 2011 a1278 that got soup spill on. At first only battery not detected so it only worked with magsafe connected, everything else worked, then I wanted to fix it, cleaned it then bad thing happenned, now No Backlight. I measured the high voltage at the PPVOUT_SW_LCDBKLT at C9020 ( right at the LVDS connector but I only got about 12V, the LCD display and LVDS cable are good ( tested on another good Macbook), I can see the display data on screen and external display ok.
Do you think the LP8550 WLED driver chip is bad ? and where could I find one.
Thanks
 
macbook pro no baclight

naKruul said:
Holy cow! guess what, my macbook is back on duty :)

i ordered the samples from NS and it took only 2 days shipping from singapore to germany with UPS Worldwide express. Thanks National :)

only thing i experienced is: the new chip does not have dithering, so you see the dimming steps. but thats a flaw i can live with.

thanks Dadioh for your support. and if anyone ever needs a LP8550 do not hesitate to contact me. or otherwise just get some samples from NS :)
Click to expand...
Hi naKruul,
i have the need for one LP8550 could you send me one.
Thanks
 
willko said:
Hi all,

Finally got some pictures... This is a MBP 15" 2009 logic board 820-2533-B. Also learned its not easy to get macro shots..! Hope these work.

I'm essentially trying to locate the fuse and the WLED, but as you'll notice the LVDS connection (I-PEX) may also have some issues... If someone could point out these parts I'll grab the multimeter.

And the TDK chip,... believe it or not a pencil fell on the board and chipped the corner - it hasn't appeared to affect anything, still the same issue, no backlight, everything else runs well via ext monitor and/or with a flashlight on LCD screen.

Many many thanks!!
Click to expand...

ROFL your LVDS connector on the left hand side looks EXACTLY like mine! What a coincidence. If you haven't checked the fuse I would check that but it's likely your LVDS connector that needs to be replaced. I can clearly see pins being cut on the far left hand side which is I believe the pins 38, 39 and 40 which provide power to the LEDs. Mine looks almost exactly the same as yours. I tried to bridge the pins thinking that would work but gave up. But I'm curious to find out how yours ended up like that. It looks like the plastic is melted a tad bit also... very similar to mine but I used a soldering iron on mine which caused a little bit to melt.

2z74rqv.png
 
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Thanks for the replies!

kilgrinus said:
Here you go
Click to expand...

Thanks very much for that! Very helpful! I'll grab the multimeter :) I guess the fuse is the first to check (I look for an open connection is that right?) But , I fear as PRJ suggested, the LVDS is looking quite unhealthy too.

PacificRimJob said:
ROFL your LVDS connector on the left hand side looks EXACTLY like mine! What a coincidence. If you haven't checked the fuse I would check that but it's likely your LVDS connector that needs to be replaced. I can clearly see pins being cut on the far left hand side which is I believe the pins 38, 39 and 40 which provide power to the LEDs. Mine looks almost exactly the same as yours. I tried to bridge the pins thinking that would work but gave up. But I'm curious to find out how yours ended up like that. It looks like the plastic is melted a tad bit also... very similar to mine but I used a soldering iron on mine which caused a little bit to melt.
Click to expand...

LOL! Very interesting! I wonder if the water damage has the effect of "frying" those LVDS connections... If they are bridged by conductive fluid maybe the power is enough to cause this type of damage..? I can't explain the plastic melting, no one has worked on it AFAIK... I totally agree with you re: this is more than likely a cause ( if not THE cause...) I can't see a simple fuse replacement fixing this... Looks like I'll have to replace this but I would not even know where to start.... I recently bought a BK6000 solder station with hotair of eBay and I've worked on some fairly small stuff but this is new to me... Any idea where I would find a guide or some tutorials on a job like this? I have plenty of dead PCBs with somewhat similar components to practice on.

Cheers guys!
 
MacBook Pro 13" DEAD

Hi all, (my English is bad, so i am mostly copying and pasting...)

I enjoy reading this forum, specially we have Dadioh help with his expertise and dedication.

I have a macbook pro 13 2.26 (mid 2009)

My logic board is the exact copy as the
https://forums.macrumors.com/attachme...4&d=1305808864

The macbook had for a couple of days overheating issues and then came death.
No power, no light on the magsafe adapter.

Any help/ideas ?
 
Hi,

first I want to thank all the people who helped in this thread, very much helpful experiences and informations!

I have a late 2008/early 2009 Macbook Pro 13" (Aluminium Unibody) (P8700 CPU) here with no backlight.

I measured nearly every resistor in the wled circuit, the fuse and the pins of the wled driver.
The fuse is ok, the Wled driver seems to be blown and some resistors seem to be done (0v output on one side).
The pins for backlight on the lvds connector get about 12v.

I ordered the WLED Driver (LP8543) and all resistors of the wled circuit to have everything here i could need.

But now I have the problem to clearly see which resistor is on which place, because measuring of the dead resistors doesn't show me the right data.

Does anybody has a board view of the 13" MBP or could help me which one I need if I post a picture and mark the dead resistors?
 
it looks like the newer Macbook Pro uses a BGA chip as the WLED driver. The logic board is 820-2914-A. Can anyone confirm that this is the WLED driver ?

2z3t45t.jpg
 
wickawack said:
First off, thanks for getting back to me so quickly. Funny you mention this. Laptop was already on it its side with the back off and the battery taped in. I removed the bracket and the problem seems independent of LVDS cable wiggling. I've already removed the clutch cover (plastic thing covering the guts of the hinge) and checked that there was no place where the fabric cable cover had been worn through.

I've linked a video of the issue at the end of this post. This was done without the back on, so the problem is independent of the back cover being on or off. As can be seen, sometimes it stays in the 'on state' and sometimes it stays in the 'off state.' Any ideas? Is it more likely to be a short or a break in a solder joint?

Also, I'm sure flexing the case like that isn't a good idea but when the backlight turns off, it is the only way to get it back on, albeit temporarily. I pretty much only use it with an external monitor, but finally decided to do some investigating.

Video of backlight turning on and off with force.
Click to expand...

Sorry to bump my own post, but does anyone know what components would be best to check on the board? I've got a multimeter and the schematics for the 15" A1286. It seems that I'd want to check everything on the PPVOUT_S0_LCDBKLT path. Does anyone have the locations of the components or a link to detailed blow ups of the board? I'm currently on a mac and can't use the boardviewer.exe app.

Thanks again.
 
naKruul said:
Well, technically not. But you could at least contribute to Dadioh in any way if you use his expertise to gain money.
Click to expand...

No no no. I contribute along with others to this thread. I don't expect any sort of compensation and have turned down kind offers from some. This is a fine community of users and I enjoy giving back in any small way.
 
Hi all,

I was wondering if someone could point me to a place to find & purchase the parts I will need to fix (or attempt to fix) the system board... I was going to order the fuse (?), the WLED chip (L8543SQ) and a new I-PEX LVDS connector. (previous post with pictures just a few posts above).

Found these videos very helpful:
http://www.youtube.com/watch?v=3NN7UGWYmBY
http://www.youtube.com/watch?v=c_Qt5CtUlqY

Now practicing on some dead PCBs :)
 
willko said:
Would these be correct:

http://www.ebay.com/itm/NEW-I-PEX-4...-LCD-LOGIC-BOARD-LVDS-CONNECTOR-/120909394466

http://www.ebay.co.uk/itm/1x-NEW-NS-L8543SQ-QFN-24pin-Power-IC-/180845677360

not sure about the fuse,... any clues?

EDIT - Ahh,, found this from one of Dadioh's earlier posts:
http://www.digikey.com/product-detail/en/LP8543SQ/NOPB/LP8543SQ/NOPBCT-ND/2353187?cur=USD
Click to expand...

Is this a 15" Macbook Pro? The 15" uses a 40 pin connector which is correct for what you have linked. The 13" uses a 30 pin connector.

If you want to get the parts in one spot and save on shipping I have bought quite a few parts from this online store. Fast shipping and good service.

http://www.ebay.ca/itm/5x-NEW-ISL62...ultDomain_0&hash=item4cfba5898c#ht_1208wt_914

http://www.ebay.ca/itm/NEW-OEM-I-PE...es_Adapters&hash=item3a78291f1c#ht_1286wt_914
 
willko said:
Hi all,

I was wondering if someone could point me to a place to find & purchase the parts I will need to fix (or attempt to fix) the system board... I was going to order the fuse (?), the WLED chip (L8543SQ) and a new I-PEX LVDS connector. (previous post with pictures just a few posts above).

Found these videos very helpful:
http://www.youtube.com/watch?v=3NN7UGWYmBY
http://www.youtube.com/watch?v=c_Qt5CtUlqY

Now practicing on some dead PCBs :)
Click to expand...

I have seen those videos before and they do have some really nice tips. But be aware, he is showing soldering on what looks like a 2 layer circuit board with sparse component population. In real life, on a Macbook, you are looking at 12 to 16 layer circuit boards (which wick away heat very fast) with very dense layout and a lot of 0402 size parts. So it takes a LOT more heat and patience to achieve results.

Just to let you know before you are greatly disappointed in how easy he makes it look and trying to figure out why it isn't working so easily for you :D
 
Dadioh said:
I have seen those videos before and they do have some really nice tips. But be aware, he is showing soldering on what looks like a 2 layer circuit board with sparse component population. In real life, on a Macbook, you are looking at 12 to 16 layer circuit boards (which wick away heat very fast) with very dense layout and a lot of 0402 size parts. So it takes a LOT more heat and patience to achieve results.

Just to let you know before you are greatly disappointed in how easy he makes it look and trying to figure out why it isn't working so easily for you :D
Click to expand...

Hi, thanks for the advice.
Is it necessary to preheat the board, or is it possible to solder it without preheating?
Best regards
 
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