Hi Dadioh. First I like to thank you for the thread. It is very helpful. Second I have a Macbook Air 13 inch 2012 model A1466. last 4 digit of serial number is DRVC. I spilled some tea on it. after drying it and cleaning the motherboard the laptop turns on but I get no backlight. I can see the screen on but very very dark. I thought it was the fuse. I have looked everywhere for it and can't find the fuse. I was looking for something small with a white dot or F marking. I was wodering if you could help me find the fuse or provide me with some schematics for this logic board. do you think ts on the same side as the LVDS cable or the opposite side?your help is much appreciated.
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MacBook Pro Unibody - No Backlight - Logic Board Question
- Thread starter Dadioh
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I have not performed a boundary scan (measuring resistance to ground on all pins) of the LP8550 yet. Because it is a BGA package there is no direct access to the pins so you would have to measure where the tracks that come out from beneath the chip terminate. Or use the schematic to find where they terminate.
I don't have tome at the moment to do this. If someone has done this already could they please share? Boundary scans are a very useful tool in identifying bad parts.
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If you can take some high resolution pictures of the front and back of the logic board and post here I will see what I can find. I have only seen schematic for 2010 MBA but it may be similar to 2012?
I will take pics when I get home today. Would you be able to send me the schematic for the 2010 model? as you said it might be similar.
To give at least a little something back to the community, I compiled some information for the Macbook Pro 13" early (and late) 2011.
First things first. ID your board.
Look on your board for the serial number. It should read 820-2936-B (or something very close to this).
Look here:
Frequently asked questions:
Where is the fuse?
Near the LVDS connector. A bit to the left, it should have a P on it.
What kind of fuse is it?
3A, 32V, fast acting, 0603 package.
This is actually what the "P" tells you. See here: http://www.matronic.com/pdf/herstellerkataloge/littelfuse_katalog/Chapter10SurfaceMountFuses.pdf
Any fuse with this specs will work. If you want the fancy "P" on it, get one from "littlefuse".
There is something wrong with my LVDS connector (burned down pins, etc.), what kind of connector is it?
It's an I-PEX 20474-030e-11 (30 pins. Note the "030e"). Either search for this and get them cheap from asia, or search on ebay for "Macbook 2011 lvds connector" and pay more.
Where is the WED driver?
Look left from the Fuse. A tiny BGA package surrounded by resistors. See picture.
Where can I get one of these?
It's a relabeled Texas Instruments LP8550. Either order at least 500 of them from TI or, register as a company on their site and order some free samples. A third option would be ebay again. There are some sellers who offer them.
What do I need to do this myself?
If you need to ask this question, you should really consider to hire a professional to do this.
Where can I find schematics of my board.
Just google your board number and don't be lazy. There are a lot of shady websites who want to sell them to you. I would not recommend to buy from any of those. You can find a lot of russian, chinese, polish, etc forums where people post pdf schematics.
First things first. ID your board.
Look on your board for the serial number. It should read 820-2936-B (or something very close to this).
Look here:
Frequently asked questions:
Where is the fuse?
Near the LVDS connector. A bit to the left, it should have a P on it.
What kind of fuse is it?
3A, 32V, fast acting, 0603 package.
This is actually what the "P" tells you. See here: http://www.matronic.com/pdf/herstellerkataloge/littelfuse_katalog/Chapter10SurfaceMountFuses.pdf
Any fuse with this specs will work. If you want the fancy "P" on it, get one from "littlefuse".
There is something wrong with my LVDS connector (burned down pins, etc.), what kind of connector is it?
It's an I-PEX 20474-030e-11 (30 pins. Note the "030e"). Either search for this and get them cheap from asia, or search on ebay for "Macbook 2011 lvds connector" and pay more.
Where is the WED driver?
Look left from the Fuse. A tiny BGA package surrounded by resistors. See picture.
Where can I get one of these?
It's a relabeled Texas Instruments LP8550. Either order at least 500 of them from TI or, register as a company on their site and order some free samples. A third option would be ebay again. There are some sellers who offer them.
What do I need to do this myself?
If you need to ask this question, you should really consider to hire a professional to do this.
Where can I find schematics of my board.
Just google your board number and don't be lazy. There are a lot of shady websites who want to sell them to you. I would not recommend to buy from any of those. You can find a lot of russian, chinese, polish, etc forums where people post pdf schematics.
Hey Dadioh, thanks for your effort!
I could not really trace the connections because I don't want to remove a potentially healthy WED chip just yet. A friend of mine has the same board as I do and I did some measurements on a healthy board (everything around the WED).
Then I measured on my board, and I noted some differences.
I marked every different reading in the picture below. What really bugs me is the resistance just below the chip, which is like 9,5M Ohms difference, and the one right next to the fuse. Which has no continuity to ground at all.
Do you know where I can find the boost diode?
Is it the black package on the left, labeled F03AY5?
When the macbook is running, I measure 0,2V there.
jrumball
macrumors newbie
Early 2009 MBP Distorted No video on LCD
So.... this seems like the best place to post this
I have a Early 2009 MBP 15.4 2.8 C2D 8gig Ram 512mb Nvidia 9600m GT with shared 9400m 1680x1050 matte LED LCD 750gig Disk osx 10.8.3
I purchased a MBP on Ebay the only problem that was mentioned was a flashing question mark in a folder, and what looked like to be a flaky display cable the screen went on and off with the movement of the hinge and explicitly no liquid damage, I thought I had got lucky as i won it for £300 popped in a new disk and replaced the HD cable, replaced the display cable, it was a matte model so at the same time I upgraded the display to a 1680x1050 LCD and away I went. All has been good for the last 6 months.
In the last week I have been having major display issues with the internal LCD, I could resolve these by putting pressure on the left hand speaker grill above what I now know to be the WLED driver. Initially this seemed to coincide with the cooling of the machine ie after graphically intensive activity which is what lead me to reflow both GPUs as I have seen conflicting reports of whether some 9600m cards had similar problems to the 8600m
The machine works perfectly closed with an external display via Mini DP to VGA adapter, what I'm typing this on now ! Which makes me suspect somthing post GPU, to do with the LCD output stage.
Using gfx control to force both GPUs these problems still happen on both
Symptoms
Distortion on the internal LCD from boot, tearing the screen going black, the back light still functions %95 of the time.
The machine will occasionally hang just after login in OSX and hangs after the windows login screen too.
When it hangs in osx it reports back with an Nvidia Driver error on next login.
All of these happen in both osx and windows.
What I have tried in no particular order
-Reset pram and smc
- removed reseated and swapped RAM
- buzzed out replaced LVDS cable and swapped cable and original display
-selectively reflowed both GPU and GPU/northbridge with hot air
-baked whole Logic board in oven in an attempt to catch a dry joint I hadn't noticed
-replaced heat transfer compound
- carefully inspected logic board and LVDS connector no glaring problems
-checked back light fuse
-swapped mag safe adapters
-booted from usb installer disk
.....none of this has made it better or worse but the issue is still present....
Anyone have any ideas, I'm thinking bad GPU, or broken trace on Logic Board some where, or something to do with the WLED Controler but am open to try anything else to get it working...
Have tried a few more things but its late and can't remember...... 😕
Many Thanks for reading all of my waffle
So.... this seems like the best place to post this
I have a Early 2009 MBP 15.4 2.8 C2D 8gig Ram 512mb Nvidia 9600m GT with shared 9400m 1680x1050 matte LED LCD 750gig Disk osx 10.8.3
I purchased a MBP on Ebay the only problem that was mentioned was a flashing question mark in a folder, and what looked like to be a flaky display cable the screen went on and off with the movement of the hinge and explicitly no liquid damage, I thought I had got lucky as i won it for £300 popped in a new disk and replaced the HD cable, replaced the display cable, it was a matte model so at the same time I upgraded the display to a 1680x1050 LCD and away I went. All has been good for the last 6 months.
In the last week I have been having major display issues with the internal LCD, I could resolve these by putting pressure on the left hand speaker grill above what I now know to be the WLED driver. Initially this seemed to coincide with the cooling of the machine ie after graphically intensive activity which is what lead me to reflow both GPUs as I have seen conflicting reports of whether some 9600m cards had similar problems to the 8600m
The machine works perfectly closed with an external display via Mini DP to VGA adapter, what I'm typing this on now ! Which makes me suspect somthing post GPU, to do with the LCD output stage.
Using gfx control to force both GPUs these problems still happen on both
Symptoms
Distortion on the internal LCD from boot, tearing the screen going black, the back light still functions %95 of the time.
The machine will occasionally hang just after login in OSX and hangs after the windows login screen too.
When it hangs in osx it reports back with an Nvidia Driver error on next login.
All of these happen in both osx and windows.
What I have tried in no particular order
-Reset pram and smc
- removed reseated and swapped RAM
- buzzed out replaced LVDS cable and swapped cable and original display
-selectively reflowed both GPU and GPU/northbridge with hot air
-baked whole Logic board in oven in an attempt to catch a dry joint I hadn't noticed
-replaced heat transfer compound
- carefully inspected logic board and LVDS connector no glaring problems
-checked back light fuse
-swapped mag safe adapters
-booted from usb installer disk
.....none of this has made it better or worse but the issue is still present....
Anyone have any ideas, I'm thinking bad GPU, or broken trace on Logic Board some where, or something to do with the WLED Controler but am open to try anything else to get it working...
Have tried a few more things but its late and can't remember...... 😕
Many Thanks for reading all of my waffle
Dadioh, I have the same motherboard as Mori3000. its a 820-3209A. seems like the WED chip is not the typically used LP8550. Its apple proprietary. I have taken pics from the front and back of the board. Can you please help me identify the fuse? Please make marking on my pics as you wish. Mori3000 feel free to offer your insights since you have worked with this motherboard. btw this is for a 2012 macbook air.
Thanks guys
Thanks guys
Attachments
I have actually found the fuse. Its marked with a P on it. I have indicated on the pic below. I tested the fuse and it was bad. So i have changed it. The fuse is good now but i still don't get any Backlight. I think the FET might be bad, because I'm not getting any voltage from Pin 1, 2, 5, 6. Pin 3 and 4 both have 7 volts on them.
any idea what to look for next?
any idea what to look for next?
Attachments
See below. It has a "P" on it like it seems all of the other Macbooks 2011 onwards have.
edit: I see you found it. Was reading oldest to newest.
Attachments
Yes. That looks like the boost diode. That feeds into the 2 caps above it which smooth the waveform. Even with non-boosting WLED driver you usually get 12V on the cathode (the end with the line on it). Trace back in the schematic from the fuse through the FET to the inductor and then diode and see where the 12V stops. That same 12V also feeds the enable pin of the WLED driver through a 301K/100K resistor divider. I have seen those resistors fail before.
By the way. Excellent photos and detailed information. Unfortunately I am not as familiar with the 2011 as I am with the earlier 2008-2010 boards and I just don't have the time right now to look in detail at one of my boards. There is a board view file for this schematic so you will need to figure out which spots in the schematic are reading those wrong values and try to go from there. It is laborious but the only way tp learn it.
Good Luck.
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Macbook A1342 2010 Polycarbonate
Hello, I am looking for Macbook A1342 Polycarbonate Unibody board view file if anyone can please help? The logic board I am working on is having power problem so need identify some critical power section components.
Thanks
Hello, I am looking for Macbook A1342 Polycarbonate Unibody board view file if anyone can please help? The logic board I am working on is having power problem so need identify some critical power section components.
Thanks
Hey Guys!
Been following this thread for a long time and finally decided to join up and try and fix my wife's Macbook!!
Wife has a late 2008 13-inch Aluminum Macbook that she spilled iced tea on. Finally sputtered out and died. I ordered a new logic board a while back off of eBay and it worked perfectly for a couple months. Then the backlight on the screen went out (including the light on the reverse side for the apple emblem). I believe it is the fuse. Just to keep things quick and easy, should I upload a pic of certain parts of the logic board to identify the the fuse or other parts I should check for damage? Like I said, I have been reading through the thread, but seems to be a wide variety of logic boards being addressed. I am pretty tech savvy and can take direction well, and can do some basic soldering. Just hoping to fix this for less then $100 which I could buy another logic board from ebay for. Thank for any help 🙂
-Jeff
EDIT: Added some images...
Been following this thread for a long time and finally decided to join up and try and fix my wife's Macbook!!
Wife has a late 2008 13-inch Aluminum Macbook that she spilled iced tea on. Finally sputtered out and died. I ordered a new logic board a while back off of eBay and it worked perfectly for a couple months. Then the backlight on the screen went out (including the light on the reverse side for the apple emblem). I believe it is the fuse. Just to keep things quick and easy, should I upload a pic of certain parts of the logic board to identify the the fuse or other parts I should check for damage? Like I said, I have been reading through the thread, but seems to be a wide variety of logic boards being addressed. I am pretty tech savvy and can take direction well, and can do some basic soldering. Just hoping to fix this for less then $100 which I could buy another logic board from ebay for. Thank for any help 🙂
-Jeff
EDIT: Added some images...
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The fuse on the 2008 is on the back. I know I uploaded an image a long time ago but the thread is so large it may be difficult to find. I am traveling right now and don't have access to my imac but if you post a picture of the back I can point out the fuse.
Hey Dadioh!
The photos where made with a 60 bucks usb microscope I bought for my local hackspace.
After countless hours of searching through russian and chinese forums, I found some software which allowed me to identify the parts from the schematic. The thing I assumed to be the boost diode was actually a diode from a completely different area of the board! I found my missing components on the back of my logic board (alongside some more residue I missed 🙁 )
I hope those pictures with the part numbers will help others aswell:
Could you please take a look at my readings? My understanding of electronics is not that good that I could make sense out of the schematic 🙁
I measured the voltage at every point I could reach.
I also noticed some values of the resistors which are not really in the tolerance:
R9716: 87,6k
R9715: 94k
R9714: 15k
I dont really know if that makes a difference.
My multimeter also has quite some difficulties to correctly measure R9731, but after some time it says 300k.
Could you help me pinpoint the broken part?
Thanks in advance!
Yes, its P,i checked it with multimeter, and it has signal from the other side to the other,i'm bad in english grammar about technology,anyway thank you for your reply, i'll try to change that fuse, maybe its gonna work 🙂
Weird LCD problem just arisen
Macbook Pro was working fine, shut it down, a couple of days later tried to turn it on, the white/grey screen comes up, it chimes, then before the Apple logo appears and the spinner starts to indicate the OS is booting, instead the white/grey screen fades to black.
Upon further investigation, it seems like its booted up but the LCD has powered off.
If I press the power button after it has booted, I can hear HDD activity whilst it goes into sleep mode.
Once its gone into sleep mode, I can't wake it however, subsequent press of the power button makes the led on the front illuminate as if its coming out of sleep mode but a few seconds later if starts snoring again.
If I didn't know any better, I would say the back light on the LCD had gone, but it hasn't. If I force power it off and then power it back on again, I can get the breif illumination of the white/grey screen before the same thing happens.
Macbook Pro was working fine, shut it down, a couple of days later tried to turn it on, the white/grey screen comes up, it chimes, then before the Apple logo appears and the spinner starts to indicate the OS is booting, instead the white/grey screen fades to black.
Upon further investigation, it seems like its booted up but the LCD has powered off.
If I press the power button after it has booted, I can hear HDD activity whilst it goes into sleep mode.
Once its gone into sleep mode, I can't wake it however, subsequent press of the power button makes the led on the front illuminate as if its coming out of sleep mode but a few seconds later if starts snoring again.
If I didn't know any better, I would say the back light on the LCD had gone, but it hasn't. If I force power it off and then power it back on again, I can get the breif illumination of the white/grey screen before the same thing happens.
Maybe bad sleep sensor. You didn't say which model you have but if it is a 13" then the sleep sensor is in the battery indicator light (BIL) cable. To troubleshoot, unplug that cable from beside the battery connector. If the problem goes away then it is the BIL.
Thats a P-Channel Power MOSFET. Part no.HAT1127H. If you just google it you will find the datasheet for that.
Dadioh, I'm running out of ideas right now.
I just changed the WED driver, tried to measure the outer balls of the BGA LP8550 to what they are supposed to be connected to, hooked up my Display, and... nothing... still no backlight. 🙁
Do you have any other hint for me?
Is there perhaps a way to check the functionality of the WED driver? Personally I cannot make much sense out of it.
Hi Dadioh,
Thanks for the reply, I will try your test later today.
I also found another thread that sounded plausible and I would have never guessed this if I hadn't read it somewhere. Someone suggested they had a similar problem with a stuck F1 key. I think when a Macbook powers on, it starts with a fixed brightness setting, the stuck F1 causes the screen to dim to nothing which might explain the fade out I'm seeing.
If it is a stuck F1 key on my keyboard, I haven't been able to free it, so it may need a replacement keyboard but I guess I could try a similar test when I take the bottom off by disconnecting the keyboard connector too.
Thanks
Dave.
I had thought of mentioning the stuck brightness key but when I read your description of the behavior of the sleep LED it sounds like it is more than just the screen brightness, Sounds like it is being forced to sleep and screen brightness would not do that. Let us know how it goes either way.
In case someone could use the test points for the LP8550, I traced the connections from the BGA:
