MacBook Pro Unibody - No Backlight - Logic Board Question

[willko]

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

Thanks for the heads-up! Very helpful info re: the density/layering issues! I get your point, the videos are "rose tinted" so to speak The MBP I have is the 15" A1286 2009 (so 40 pin I-Pex) and thanks again for the supply links!

I have some fairly dense PCBs from some dead laptops and phones to practice on and a friend has a good metallurgy microscope for me to play with. Besides, I'm very good at jenga lol! Does it sound defeatist if I say I am prepared for the worst..? I've already written off this logic board so its really an exercise in possibility

Many many thanks for your help and inspiration!!!!!

 

[jayjohn]

I want to share my experiences, maybe it helps someone.
Unsoldering the Wled driver worked for me that way (with a cheap hot air soldering station)
Cover the parts around the chip with kapton tape.
Add flux around the wled driver.
Heat with a nozzle that's big as the chip, low airflow, 400°c and 20-30cm distance about 5 minutes, move the hot air gun in small circles over the wled driver.
Then use more airflow and pull the hot air gun up to 480°c, less distance to the wled driver, moving in small circles over it.
After a very short time heating with 480°c I was able to lift the chip with a tweezer.

That's it. Not very hard at all, but it's a little bit scary for me to work on such an expensive part with cheap tools

 

[jos2012]

no backlight and trackpad not working

Hi all,
I have my MacBook pro 13in early 2011 that currently has two problems :
1. No backlight : I already replace the lvds connector but the boost voltage still stays at 12v, checked all components such as resistors, caps diode and inductance they are fine, so I concluded that the ti(national semi) LP8550 chip is faulty
2. The trackpad does not worked properly, replaced a new trackpad did not help, checked out that the chip TI tps61045 is faulty, its output stays at input voltage 5v instead of boosting it up to 18.5v.
So anyone can help me to find those chips at reasonable price?
thanks in advance.

 

[PVZ]

MBA 11' A1370 no backlight

Hi all,

I've been searching for a while now and although it seems I'm not the only one with this problem, I can't find a solution to the problem.

I've replaced the lcd from my MBA 11' A1370. All is fine, the lcd works, but now the backlight isn't working.
I've swopped the new lcd for the old one to see if that would make the backlight working again, but no.

Does anyone have a solution? Is there anyone who had this problem that can tell me how they fixed the problem.

I've added a picture of the motherboard. Maybe that helps.

I would be very thankful for any type of help!

Thanks in advance!

 

[jayjohn]

@pvz Did you remove the battery connector as you changed the display? If I remember it right, I have read in this thread that it could damage the wled driver if the battery is connected when removing and plugging in the lvds connector.
Maybe you should measure the fuse first and then check the wled driver.

 

[PVZ]

@pvz Did you remove the battery connector as you changed the display? If I remember it right, I have read in this thread that it could damage the wled driver if the battery is connected when removing and plugging in the lvds connector.
Maybe you should measure the fuse first and then check the wled driver.

Jayjohn, thanks for your reply!
I did disconnect the battery, but when laying the laptop flat again it "connected itself" again. A very, very stupid mistake, that I easily could have prevented from happening.

Could you elaborate a little on which part is the fuse and which part is the wled driver and which readings I should get.

Thanks in advance!

 

[mullenmouse]

Yup. Those would be the backlight pins. Other pins might be a bit dull looking. First step is to replace that LVDS connector and then see.

----------

So I had the LVDS connector replaced by a 'reputable' eBay repair business. Lets just say that I won't be going back down that route...at least I found out it had suffered water damage.

There is another component on the board that has either had an attempted repair or has ruptured/blown near to the LVDS.

Can anyone identify this component? It is on the left of the attached image - I think it has 6383 stamped on it?

The board came back as an unsuccessful repair, and still does not output anything to the display, but will boot etc. I now know that the display is also water damaged, but it does work with another board, just displays vertical lines.

 

[Dadioh]

Hi all,

I've been searching for a while now and although it seems I'm not the only one with this problem, I can't find a solution to the problem.

I've replaced the lcd from my MBA 11' A1370. All is fine, the lcd works, but now the backlight isn't working.
I've swopped the new lcd for the old one to see if that would make the backlight working again, but no.

Does anyone have a solution? Is there anyone who had this problem that can tell me how they fixed the problem.

I've added a picture of the motherboard. Maybe that helps.

I would be very thankful for any type of help!

Thanks in advance!

I have never worked on that model but I "think" the fuse might be the one I have labeled. Maybe someone else can confirm. With power off and battery disconnected can you measure this component with a multimeter and tell us what it reads? A fuse should read about 0 ohms.

But it would be wise to get confirmation from someone who has this model first.

 

[jayjohn]

Jayjohn, thanks for your reply!
I did disconnect the battery, but when laying the laptop flat again it "connected itself" again. A very, very stupid mistake, that I easily could have prevented from happening.

Could you elaborate a little on which part is the fuse and which part is the wled driver and which readings I should get.

Thanks in advance!

I don't know this model, but search for "051-8925" or "K78 MLB 051-8871 820-3024 elvikom"@ google. The boardview + schematics should guide you into the right way to the parts.
Because I don't know and don't have the board I can't tell you exactly what's the right measurements for the wled driver, but if you find it on the schematic, you should be able to find the datasheet of the part which could give you more informations, so you can measure at least if the right voltage output/input is on the pins and which pins are connected to gnd, so you can even test if there is a short to gnd.
Maybe someone know more, at the moment this is all help I can provide for that board, I hope it helps you a bit.

 

[PVZ]

I have never worked on that model but I "think" the fuse might be the one I have labeled. Maybe someone else can confirm. With power off and battery disconnected can you measure this component with a multimeter and tell us what it reads? A fuse should read about 0 ohms.

But it would be wise to get confirmation from someone who has this model first.

Thanks Dadioh for your reply.

The component we think is the fuse reads 0 ohms. This means it is a closed circuit and therefor not broken right?
Are there any other components to check for me?

I really appreciate the help!

Thanks again!

 

[Dadioh]

Thanks Dadioh for your reply.

The component we think is the fuse reads 0 ohms. This means it is a closed circuit and therefor not broken right?
Are there any other components to check for me?

I really appreciate the help!

Thanks again!

I would focus on the LVDS connector next. It is possible during the swap that there are damaged pins. It is a very fragile connector. I have no idea which pins are the backlight pins however unless Apple used the same pinout as the MBP13's....

If you can get some magnification look into the end opf the LVDS connector and see if the pins look OK.

 

[grize]

Please could I have some help locating the WLED on this board? It is from a MBP 15" early 2011 i7. Logic board p/n: 820-2915-B. Thanks

 

[l.a.rossmann]

Well, technically not. But you could at least contribute to Dadioh in any way if you use his expertise to gain money.

Good point. I'm playing devil's advocate. I love helping people, but some of the entitled sounding phone calls I get where people use me as an encyclopedia over the phone during business hours can drive me crazy.

----------

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

Yeah that QFN video is total crap if you're dealing with a Unibody motherboard. Or almost any laptop motherboard!

There are dozens of tiny components around every QFN. By the time you're using enough power to get the QFN to settle, you've blown away all the 0402s around it, if you are not careful.

Get some kapton tape and put it around the QFN you are soldering. If you don't you will make your life miserable until you get the hang of it. It'll save you a lot of heartache finding them and reattaching them.

Those QFNs are so small that while putting solder on the outer pads it is very easy to get some solder on the center pad. The other difficult part is not moving components nearby. It is also very easy to heat the QFN and have it never actually connect to the board.

----------

I have never worked on that model but I "think" the fuse might be the one I have labeled. Maybe someone else can confirm. With power off and battery disconnected can you measure this component with a multimeter and tell us what it reads? A fuse should read about 0 ohms.

But it would be wise to get confirmation from someone who has this model first.

I'll be able to confirm at the office before the weekend if that's the fuse on one of my air test rigs. It's 2:51 AM and my eyes are glazing over. I promise, I will check and confirm!!

 

[thebeeobee]

Hi guys,

Thanks for this great resource!

Ok, I spilled water on my macbook pro last week...I sat it upside down for the night and the next day it worked fine...until it went to sleep at one point and the screen didn't wake up from the sleep...but i could see in the sunlight that the image was still there so it had to be the backlight. That's when I searched and found this post.

I was ready to open it up today, finally, and clean everything with alcohol and hopefully test the fuse...when I started up the mac this morning, the backlight WORKED. For the first time in over a week, it worked fine! I tried switching graphics cards (15" Macbook Pro 5,1), putting it sleep from closing the lid, from letting the screen timeout, restarted, etc...and the backlight kept working.

UNTIL...about 3 hours later, it just turned off again. I didn't move the computer at all...it was just sitting on my desk while I was reading and it shut off.

So, based on this information, can you help me diagnose what the problem might be? I was only going to check the fuse, originally, but considering the fact that the screen worked today, can I assume it was something else? If so, what?

Thanks for your time and any advice you can give me.

Bob

 

[Dadioh]

Hi guys,

Thanks for this great resource!

Ok, I spilled water on my macbook pro last week...I sat it upside down for the night and the next day it worked fine...until it went to sleep at one point and the screen didn't wake up from the sleep...but i could see in the sunlight that the image was still there so it had to be the backlight. That's when I searched and found this post.

I was ready to open it up today, finally, and clean everything with alcohol and hopefully test the fuse...when I started up the mac this morning, the backlight WORKED. For the first time in over a week, it worked fine! I tried switching graphics cards (15" Macbook Pro 5,1), putting it sleep from closing the lid, from letting the screen timeout, restarted, etc...and the backlight kept working.

UNTIL...about 3 hours later, it just turned off again. I didn't move the computer at all...it was just sitting on my desk while I was reading and it shut off.

So, based on this information, can you help me diagnose what the problem might be? I was only going to check the fuse, originally, but considering the fact that the screen worked today, can I assume it was something else? If so, what?

Thanks for your time and any advice you can give me.

Bob

When a fuse blows it is a one way ticket so you can't get that sort of on-again off-again behaviour. But can't rule out that the last off-again event wasn't the fuse finally blowing. Open it up, disconnect the battery, and have a good look. Under magnification if possible. Clean all the corrosion front and back. Then see how it is behaving and take it from there.

Welcome to the thread....

 

[thebeeobee]

When a fuse blows it is a one way ticket so you can't get that sort of on-again off-again behaviour. But can't rule out that the last off-again event wasn't the fuse finally blowing. Open it up, disconnect the battery, and have a good look. Under magnification if possible. Clean all the corrosion front and back. Then see how it is behaving and take it from there.

Welcome to the thread....

Thank you. I will clean it tonight. I got alcohol and a new toothbrush like I saw suggested earlier in this thread.

I just got it turn on again after about an hour of letting it sit... could it be a heat thing? a sensor?

I will get back to you after a visual inspection. Thanks again.

 

[Dadioh]

Thank you. I will clean it tonight. I got alcohol and a new toothbrush like I saw suggested earlier in this thread.

I just got it turn on again after about an hour of letting it sit... could it be a heat thing? a sensor?

I will get back to you after a visual inspection. Thanks again.

If it works cold but then shuts off hot that could be a solder joint issue. It is possible the corrosion has eaten away a solder joint which gives it intermittent contact. Due to differing Thermal Coefficients of Expansion (TCE mismatch) you can get the component and the board moving at different rates and opening up the contact. Solution is to resolder that joint. Look for bad solder joints under magnification.

 

[naKruul]

Please could I have some help locating the WLED on this board? It is from a MBP 15" early 2011 i7. Logic board p/n: 820-2915-B. Thanks

there you go:

i assume it is the same as in the 2011 macbook airs and 13" pros: National LP 8550
btw: what a mess. you definetly need to clean that board, especially the area around the LED Driver.

 

[grize]

there you go:


i assume it is the same as in the 2011 macbook airs and 13" pros: National LP 8550
btw: what a mess. you definetly need to clean that board, especially the area around the LED Driver.

Brilliant! Thanks a lot for the reply. The nasty looking mess around the fuse and WLED area is just some dried flux. I was struggling to read the writing on the chip, so I wiped a small amount of liquid flux over the area to see if it made the writing any easier to read. I'll get it cleaned up and measure the resistance to ground for each of the pins on the WLED.

Thanks again for the help.

 

[MacModMachine]

Alot of water damaged boards i get i soak for 1-2 hours in 99% iso alcohol and brush with a firm toothbrush and clean it.

it brings back most of those boards.

 

[PVZ]

I would focus on the LVDS connector next. It is possible during the swap that there are damaged pins. It is a very fragile connector. I have no idea which pins are the backlight pins however unless Apple used the same pinout as the MBP13's....

If you can get some magnification look into the end opf the LVDS connector and see if the pins look OK.

Dadioh, thanks for your advice, again.

I've checked the LVDS connector. All looks in perfect condition. No damaged pins what so ever.

Is there any way to check if the fault is on the Screen part or on the motherboard part?
Any suggestions what else can be measured/done?

Any advice is much appreciated!

Thanks again!

----------

I don't know this model, but search for "051-8925" or "K78 MLB 051-8871 820-3024 elvikom"@ google. The boardview + schematics should guide you into the right way to the parts.
Because I don't know and don't have the board I can't tell you exactly what's the right measurements for the wled driver, but if you find it on the schematic, you should be able to find the datasheet of the part which could give you more informations, so you can measure at least if the right voltage output/input is on the pins and which pins are connected to gnd, so you can even test if there is a short to gnd.
Maybe someone know more, at the moment this is all help I can provide for that board, I hope it helps you a bit.

Jayjohn, thanks for your help!

Not very familiar with these kind of schematics, but it's worth the try.

I'm not able tot download boardview and/or schematics for the referred site. Is there anyone who has these and is willing to email them to me?

Please let me know.

Thanks again!

 

[l.a.rossmann]

Hi guys,

Thanks for this great resource!

Ok, I spilled water on my macbook pro last week...I sat it upside down for the night and the next day it worked fine...until it went to sleep at one point and the screen didn't wake up from the sleep...but i could see in the sunlight that the image was still there so it had to be the backlight. That's when I searched and found this post.

I was ready to open it up today, finally, and clean everything with alcohol and hopefully test the fuse...when I started up the mac this morning, the backlight WORKED. For the first time in over a week, it worked fine! I tried switching graphics cards (15" Macbook Pro 5,1), putting it sleep from closing the lid, from letting the screen timeout, restarted, etc...and the backlight kept working.

UNTIL...about 3 hours later, it just turned off again. I didn't move the computer at all...it was just sitting on my desk while I was reading and it shut off.

So, based on this information, can you help me diagnose what the problem might be? I was only going to check the fuse, originally, but considering the fact that the screen worked today, can I assume it was something else? If so, what?

Thanks for your time and any advice you can give me.

Bob

After liquid the board shouldn't be turned on again. Don't do a slight cleaning. Get a tupperware container, toothbrush, and isopropyl alcohol. Without an ultrasonic the best chance you have at a real cleaning is a container and filling it with 99% isopropyl alcohol so the entire board is submerged. Never turn something on after water has gotten on it without cleaning it and allowing it to dry.

----------

there you go:

Image

i assume it is the same as in the 2011 macbook airs and 13" pros: National LP 8550
btw: what a mess. you definetly need to clean that board, especially the area around the LED Driver.

Micro smd-25 sucks. I just got done doing a U4000 on an 820-2249-A with no firewire. It sucks. I never thought I'd see the day that I were happy to be working with QFN. Good luck my friend!!

The LP8550 is a whole new world of pain in the ass compared to the older 8543 and 8545.

 

[mullenmouse]

So I had the LVDS connector replaced by a 'reputable' eBay repair business. Lets just say that I won't be going back down that route...at least I found out it had suffered water damage.

There is another component on the board that has either had an attempted repair or has ruptured/blown near to the LVDS.

Can anyone identify this component? It is on the left of the attached image - I think it has 6383 stamped on it?

The board came back as an unsuccessful repair, and still does not output anything to the display, but will boot etc. I now know that the display is also water damaged, but it does work with another board, just displays vertical lines.

Anyone? I'm struggling with this.

 

[PVZ]

Dadioh, thanks for your advice, again.

I've checked the LVDS connector. All looks in perfect condition. No damaged pins what so ever.

Is there any way to check if the fault is on the Screen part or on the motherboard part?
Any suggestions what else can be measured/done?

Any advice is much appreciated!

Thanks again!

----------



Jayjohn, thanks for your help!

Not very familiar with these kind of schematics, but it's worth the try.

I'm not able tot download boardview and/or schematics for the referred site. Is there anyone who has these and is willing to email them to me?

Please let me know.

Thanks again!

Still haven't found the source of the problem yet..
Does anyone have any suggestions as to what might be the problem?
Any help would be much appreciated!

Thanks again.

 

[smircea]

Macbook Air Late 2010 A 1369 - No backlight

I spilled water on my Macbook Air Late 2010 A 1369 . Everything works perfectly, keyboard, trackpad, keyboard, sound.... I can also see the screen under a bright light, or all works perfectly when I plug it into a monitor.

I'm essentially trying to locate the WLED fuse and the WLED driver, but as you'll notice the LVDS cable may also have some issues.

Does anyone have a solution????????

What components should I check?
Need to replace the LVDS cable?
With what cleaning solution should clean the motherboard and where?

Please let me know, I would really appreciate it if you took your time to help! Thank YOU !!!