MacBook Pro Unibody - No Backlight - Logic Board Question

[Dadioh]

I have a MacBook Pro 13" that lost the backlight during a spill but also lost the ability to charge. The computer works fine on battery but won't charge. Most of the posts in this thread are related to the backlight issues common with spills but I haven't seen any mention of power issues. Has anyone tackled anything like this?

I have another thread on SMC issues that contains some info on the charging system. Check it out below.

https://forums.macrumors.com/threads/1122338/

 

[digitalplat4m]

@dadioh

Thanks to the advice you have given to other members, I ordered and replaced the fuse on my macbook pro and was able to get the backlight working again! Thank you so much!

I have however, come across another issue. Recently, whenever I start my computer, the backlight takes about 15 to 20 minutes to turn on. I can see my desktop with the help of a flashlight but as I mentioned, strangely, it takes a while before the backlight kicks in. Any idea what could be causing this?

 

[Dadioh]

@dadioh

Thanks to the advice you have given to other members, I ordered and replaced the fuse on my macbook pro and was able to get the backlight working again! Thank you so much!

I have however, come across another issue. Recently, whenever I start my computer, the backlight takes about 15 to 20 minutes to turn on. I can see my desktop with the help of a flashlight but as I mentioned, strangely, it takes a while before the backlight kicks in. Any idea what could be causing this?

Very strange. Sounds like something warming up. Does it do it only if the computer is cold? If it is already working and warm and you then restart does it work alright?

If so, it could be something related to a bad solder joint. As the computer heats up various components expand at different rates depending on their thermal coefficient of expansion (TCE). TCE is a big factor in integrated circuit package designs to ensure there are no strains on solder joints during repeated heat/cooling cycles. Sounds like something in your backlight circuit has a bad solder joint. Examine carefully under microscope if possible and consider reflowing the solder in the area.

 

[digitalplat4m]

Very strange. Sounds like something warming up. Does it do it only if the computer is cold? If it is already working and warm and you then restart does it work alright?

If so, it could be something related to a bad solder joint. As the computer heats up various components expand at different rates depending on their thermal coefficient of expansion (TCE). TCE is a big factor in integrated circuit package designs to ensure there are no strains on solder joints during repeated heat/cooling cycles. Sounds like something in your backlight circuit has a bad solder joint. Examine carefully under microscope if possible and consider reflowing the solder in the area.

Thanks for the quick reply, Dadioh. The answer to your question is yes, the backlight functions property when the system is warm so a bad solder joint sounds logical. By any chance, do you have a schematic for a macbook pro? I have absolutely no idea how to follow or find the backlight circuit. Thanks in advance.

 

[Dominik79]

Macbook A1342 MC207 no backlight

Hello,

I hope, it's the right thread to post my questions. (I'm new here)

(if not, I would appreciate if someone will put it on the right page, thanks)

As you can imagine, I did something stupid. I caused a water damage.
Well, my macbook dried for a week and it seemed to work fine again. Instead of the backlight. I can see that there's something on the display. But there's no brightness (at most one or two percent instead of hundred).

Some of you have written, that it was a hard work replacing the defect fuse (or fuses) on the logic board.

Maybe you can tell me where to buy the fuses.

I guess I won't get them in home improvement store.

Thanks a lot,

Dominik

 

[Dadioh]

Hello,
Maybe you can tell me where to buy fuses

Dominik

I think I posted a link to digikey and Newark earlier in the thread.

 

[msuc5vette]

Hi, This is a very informative thread, thanks for all the info.

I saw part way through the thread someone asked about how to resolve the no LED backlight with a 17" Macbook Pro A1297

I don't know how extensive that model is, but I have a mid 2010 with this same problem.

I bought the unit as a non-working machine with a new main board and all it needed was an LCD.

After replacing the LCD it didn't work, I noticed there was damage to the LVDS cable, so I ordered a new one, but the backlight still doesn't work.

I confirmed I can see a faint image on the display with a flashlight, and the output to an external monitor does work.

Was this issue ever resolved with a 17" MBP A1297?

I've attached some high res photos below.
4 Pics of motherboard

 

[Dadioh]

Hi, This is a very informative thread, thanks for all the info.

I saw part way through the thread someone asked about how to resolve the no LED backlight with a 17" Macbook Pro A1297

I don't know how extensive that model is, but I have a mid 2010 with this same problem.

I bought the unit as a non-working machine with a new main board and all it needed was an LCD.

After replacing the LCD it didn't work, I noticed there was damage to the LVDS cable, so I ordered a new one, but the backlight still doesn't work.

I confirmed I can see a faint image on the display with a flashlight, and the output to an external monitor does work.

Was this issue ever resolved with a 17" MBP A1297?

I've attached some high res photos below.
4 Pics of motherboard

In order to identify the fuse we are looking at the very smallest components that you see on the board and then needing to zoom in and see if there is a white dot or an "F" on the top of one of those. I will see what I can do downloading and zooming on those photos. Also, it is entirely possible that the fuse in question is on the back of the board so you will need to remove the logic board and get photos of the back. If your camera has a macro mode use that.

edit: Can't see anything zoomed in. Need higher resolution.

 

[Svoy]

Hi, Dadioh

Could you please tell me, If I put multimeter on "Ohm" with "On" sound signal and didn't get any signal during the fuse test, is that meen my fuse is burn out?
Am i right?

Thanks for your help.

 

[Dadioh]

Hi, Dadioh

Could you please tell me, If I put multimeter on "Ohm" with "On" sound signal and didn't get any signal during the fuse test, is that meen my fuse is burn out?
Am i right?

Thanks for your help.

Easy test. Just touch your meter leads together. They should beep. Now touch both ends of the fuse. It should beep again.

So it does sound like the fuse is blown.

 

[Svoy]

Easy test. Just touch your meter leads together. They should beep. Now touch both ends of the fuse. It should beep again.

So it does sound like the fuse is blown.

Thank Dadioh for quick response...

So, I guess in my situation my fuse is dead (there is no beep) ....I've already ordered fuses...by the way I have macbook pro 15 unibody A1286 and everything work well except a screen it is black...

 

[NTBservis]

Please Identifying value resistor (unit LED backlight, macbook unibody 13). Thank you.

 

[StuffmasterBen]

Please Identifying value resistor (unit LED backlight, macbook unibody 13). Thank you.

Hi,

need to identifying some resistor. I have a Mac Book Pro 13" mid 2010 with no backlight. Attached pictures show 3 circles. All 3 component are lost. Could you please identify these components. I know that the circle in the middle is the fuse (12V 2A very fast package 0402).

Many thanks!
Stuffmaster

(Sorry for my english)

http://s7.directupload.net/file/d/2627/3ykcebqa_jpg.htm

 

[udawat]

Good work. I will have a look when I get a chance and see if there are some obvious troubleshooting tips. External display works so I suspect it is not the 9400m. The fact that it was oscillating back and forth in your description may suggest some sort of intermittent connection. Check the liquid spill areas. Sometimes the liquid causes corrosion on the ends of the resistors and caps so they look like they are connected but not actually since the end solder connection rots away. Good starting point anyways. If you can get access to a microscope it would really really help. it is a whole different world when looking at these things under a microscope.

Given the history you may very well spot the problem visually.

Good luck.

Hi,
I have just finished going through a scan using this microscope on my logic board. I don't have prior knowledge of troubleshooting in the micro world but i gave it a try. I only found some traces of grease like substance around some of my resistors and caps.
Now, i am not able to trace the data signals as we have to turn the board each time a via occurs (completely lose track). Also, how to read the nVidia's BGA pins (something like matrix form, i assume - A32, J29)?
Any suggestions?

 

[mjkane]

mid-2009 A1286 2.53 logic board

Thanks to everyone for posting as I have learned quite a bit. Special thanks to Dadioh without whom, many of us would have beautifully designed door stops.



My very inexpensive/cheap multimeter shows no continuity on this tiny little fellow with the white polka dot. This I hope means that I have correctly identified the correct 2A fuse/0402 package responsible for the back light failure. If my photo is not detailed enough, please let me know and I will try to upload a better one.

Dadioh or any one else who feels qualified to let me know that would be greatly appreciated. Thanks to one and all.

Michael

 

[LeiQQ]

Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_3_5 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8L1 Safari/6533.18.5)

You would have to be a moron to not realize that taking apart the entire computer voids the warranty. The only thing that doesn’t is upgrading the HDD and ram.

so I’m wondering why he still did it.

Before you toss around "moron" labels why not find out the background. Thanks for the excellent help

I've only been reading this forum for a couple of months and it seems there is a lot of moron calling. And please don't tell me to not read if I feel offended. That's just the sort of thing I'm talking about. There are some really helpful people that post on this forum as well.

 

[Dadioh]

Thanks to everyone for posting as I have learned quite a bit. Special thanks to Dadioh without whom, many of us would have beautifully designed door stops.

View attachment 301342

My very inexpensive/cheap multimeter shows no continuity on this tiny little fellow with the white polka dot. This I hope means that I have correctly identified the correct 2A fuse/0402 package responsible for the back light failure. If my photo is not detailed enough, please let me know and I will try to upload a better one.

Dadioh or any one else who feels qualified to let me know that would be greatly appreciated. Thanks to one and all.

Michael

That looks like the fuse. If it shows open circuit and you have no backlight then you need to replace this. Somewhere back in the thread I gave some places to buy this.

Was this a liquid damaged board? If so, before replacing the fuse make sure you clean the board well to ensure that any leakage paths are cleaned up. Then replace the fuse and cross your fingers.

Good Luck.

 

[mjkane]

That looks like the fuse. If it shows open circuit and you have no backlight then you need to replace this. Somewhere back in the thread I gave some places to buy this.

Was this a liquid damaged board? If so, before replacing the fuse make sure you clean the board well to ensure that any leakage paths are cleaned up. Then replace the fuse and cross your fingers.

Good Luck.

Dadioh,
Thank you for getting back. I just ordered a few 0402 fuses from the Digi-Key link you provided, part no. 478-2857-1-ND or call (800) 344-4539. They were extremely helpful.

For others reading this thread, the technician at Digi-Key recommended to test the suspect fuse once it has been removed from the circuit board, given the 0402's tiny size, it is possible to get a false reading. Then proceed accordingly.

Will post back in a week or so once I get the part and with any luck successfully solder it in place. Many thanks again.

 

[lhkmusic]

A1297 unibody

Hi, been reading this thread and I think my Macbook Pro has the same problem, it's a A1297 17" Unibody.

The MBP had a cracked LCD so to save money I replaced myself,to save me typing here is a link to what I posted on ifixit.com -

http://www.ifixit.com/Answers/View/45085/Replacement+LCD+install+problems,+black+screen+after+boot.

I can see the desktop if I shine a flashlight onto it so it's just the backlight not working.

below are links to some pics of the front side of the motherboard as I don't want to take it all the way out if I don't have to, hopefully the fuse it on this side ...

http://i114.photobucket.com/albums/n265/remrok/P1010973.jpg

http://i114.photobucket.com/albums/n265/remrok/P1010974.jpg

http://i114.photobucket.com/albums/n265/remrok/P1010975.jpg

http://i114.photobucket.com/albums/n265/remrok/P1010976.jpg

http://i114.photobucket.com/albums/n265/remrok/P1010977.jpg

http://i114.photobucket.com/albums/n265/remrok/P1010978.jpg

http://i114.photobucket.com/albums/n265/remrok/P1010979.jpg

http://i114.photobucket.com/albums/n265/remrok/P1010980.jpg

Thanks,

Liam.

 

[Dadioh]

Hi, been reading this thread and I think my Macbook Pro has the same problem, it's a A1297 17" Unibody.

The MBP had a cracked LCD so to save money I replaced myself,to save me typing here is a link to what I posted on ifixit.com -

http://www.ifixit.com/Answers/View/45085/Replacement+LCD+install+problems,+black+screen+after+boot.

I can see the desktop if I shine a flashlight onto it so it's just the backlight not working.

below are links to some pics of the front side of the motherboard as I don't want to take it all the way out if I don't have to, hopefully the fuse it on this side ...

http://i114.photobucket.com/albums/n265/remrok/P1010973.jpg

http://i114.photobucket.com/albums/n265/remrok/P1010974.jpg

http://i114.photobucket.com/albums/n265/remrok/P1010975.jpg

http://i114.photobucket.com/albums/n265/remrok/P1010976.jpg

http://i114.photobucket.com/albums/n265/remrok/P1010977.jpg

http://i114.photobucket.com/albums/n265/remrok/P1010978.jpg

http://i114.photobucket.com/albums/n265/remrok/P1010979.jpg

http://i114.photobucket.com/albums/n265/remrok/P1010980.jpg

Thanks,

Liam.

Hi Liam. Welcome to the discussion. I tried zooming on the area near the display connector P100973.jpg since this is the most likely area for the fuse to reside. However, the resolution isn't high enough to get a good look at the smallest 0402 sized components. There is a good chance that the fuse is on the back of the logic board. All of the models I have seen the fuse is within a couple of inches of the LVDS connector either front or back so I wouldn't bother looking in the other areas of the board.

Can you try for higher res picture of the area both front and back near the display (LVDS) connector? Or, if you have a magnifying glass have a close look for yourself. The fuse on all the models I have seen is a beige colour 0402 size component with either a white dot or the letter "F" on the top.

Good luck.

 

[lhkmusic]

Hi Liam. Welcome to the discussion. I tried zooming on the area near the display connector P100973.jpg since this is the most likely area for the fuse to reside. However, the resolution isn't high enough to get a good look at the smallest 0402 sized components. There is a good chance that the fuse is on the back of the logic board. All of the models I have seen the fuse is within a couple of inches of the LVDS connector either front or back so I wouldn't bother looking in the other areas of the board.

Can you try for higher res picture of the area both front and back near the display (LVDS) connector? Or, if you have a magnifying glass have a close look for yourself. The fuse on all the models I have seen is a beige colour 0402 size component with either a white dot or the letter "F" on the top.

Good luck.

Dadioh,

Thanks for the quick response and the info. I'm going to try and sort out hi-res images in the next few days and I will post them once I have..

Cheers

 

[neorambo]

Hey Dadioh thanks for all the support on this thread. I have a 15.4 2.53 A1286 and I can't find that darn thing. I know I burned mine cause my lcd had stripes through it and I opened it and moved the connector and noticed the resolution was changing so I (like a dumbass) pulled it out slightly while it was on and it sparked and I lost the wled backlight. I searched and came across this thread. I Read through every page and looked at every image to see if any match mine and I had no luck, I purchased the fuse 0042 2amp fuse. But I am still having trouble locating it. So I am posting some images to see if you can help me find them

 

[neorambo]

Hey Dadioh thanks for all the support on this thread. I have a 15.4 2.53 A1286 and I can't find that darn thing. I know I burned mine cause my lcd had stripes through it and I opened it and moved the connector and noticed the resolution was changing so I (like a dumbass) pulled it out slightly while it was on and it sparked and I lost the wled backlight. I searched and came across this thread. I Read through every page and looked at every image to see if any match mine and I had no luck, I purchased the fuse 0042 2amp fuse. But I am still having trouble locating it. So I am posting some images to see if you can help me find them. I arrowed in one photo where I thought it was I looked at the AB0001 chip and didn't see anything near it that had a dot on it. I see one that has a 125 or 12.5 on it. you will see that in one of the images below.

 

[Dadioh]

Great pictures.

See attachments for a mapping of the backlight circuit to the circuit board.

 

[pepsimachine15]

@dadioh-

do you happen to have the schematic for the non-pro a1278 13.3"? my lvds connector is damaged and i'm trying to do some repairs, but it is difficult without the schematic. the pro 15.4" that you had posted helped, but it uses a 40 pin connector, where mine is a 30pin connector. maybe even the pro 13.3" would work.

also, when testing for the 27v output from the wled driver, does the screen need to be attached and functioning for the wled driver to output voltage? what about the lid sensor detecting the lid open as well?

thanks,
mike