MacBook Pro Unibody - No Backlight - Logic Board Question

[naKruul]

depends on your equipment. i used a 60€ hot air station. there's a guide by dadioh somewhere in this thread, since i also had no clue of hot air soldering back then.
but the process itself is kinda easy, since the driver is very small. just thorougly put kapton tape around the chip, so you are not going to blow away any other pieces.
heat it up, take it off, clean the pads on the board, apply some flux and reapply the new driver. takes about 20 minutes.

for desoldering you could possibly just put a big blob of solder on top of the old chip and heat it with a soldering iron. since the chip is so small that could work. but you'll need a hot air station for resoldering anyway.

 

[strikerba]

I've read almost 30 pages of this post and saw that you guys solved many questions 🙂 Here's my thing

While i'my waiting for replacement LVDS comes, can you confirm (or at least put my soul to rest) that these two faulty pins shown on the pic are to blame that i dont have any picture on my display. To mention, that it works perfectly on external display ! Thanx in advance

 

[strikerba]

Just to mention, that i have no backlight, or image on the screen (tried the trick with the torch)

 

[Dadioh]

I've read almost 30 pages of this post and saw that you guys solved many questions 🙂 Here's my thing



While i'my waiting for replacement LVDS comes, can you confirm (or at least put my soul to rest) that these two faulty pins shown on the pic are to blame that i dont have any picture on my display. To mention, that it works perfectly on external display ! Thanx in advance

That would be it. Pin 1 is ground but pin 2 and 3 are the 3.3V power to the LCD panel. Without that the LCD will not display anything. In fact it may not even turn on the backlight because there may be feedback to the SMC that the display is not working so do not bother turning n the backlight.

 

[strikerba]

That would be it. Pin 1 is ground but pin 2 and 3 are the 3.3V power to the LCD panel. Without that the LCD will not display anything. In fact it may not even turn on the backlight because there may be feedback to the SMC that the display is not working so do not bother turning n the backlight.

Thanx mate, that eased me a bit 🙂 Will post results when i do that tedious job of changing the LVDS cable !

 

[thebe]

Hello i have a Macbook non pro 2008 with no backlight. I messured the smale fuse on the backsite 12.5V, its working. The Power boost diode is on both sides 0 V and the enable signal for the APP001A is 0V. The APP001A should be ok i messured all resistance as showen on the first side.


Any ideas what to check now ?

 

[healeydave]

@Dadioh
Over the course of the last few days, I have just finished reading this entire thread (well I did just scan through a few replies relating to older MacBooks) 🙂

I just wanted to contribute some symptoms with one of the newer 2012 MacBooks
(Ref. Point: at the time of writing this post, this thread was 41 pages, it was Jan 2013 and the 2012 MacBooks were the newest model)

I have a A1278 2012 MacBook Pro that is literally only 6 weeks old. It was liquid damaged and the first symptom was no power. I cleaned the logic board and moved on to testing.

Shorting the pads on the logic board with tweezers (in a switch like fashion) causes the fan & hard disk to spin up for about 5 seconds before it shuts back down. What I found was if I short the pads and keep them shorted (until the gong), I can force the Macbook to boot albeit with no backlight.

Once I found I could get the unit to boot by holding the tweezers on the pads for about 5 seconds, I used a combination of SMC reset tips using both the key stroke version and the disconnecting the battery version.

After what I can only presume was a successful SMC reset, the battery started to charge but there is a strange quirk. The last Battery LED is permanently lit even without pressing the check button!
The battery proceeded to charge to 84% but then the magsafe went back to Green. So it seems its charged the battery up to the 6th LED, the 7th LED stays un-lit and the last / 8th LED is always lit, even when the unit is powered off.

Oh, it should be noted that the system will now allow me to boot it up with the power button but I have to do the same procedure as using the pads on the logic board. I have to hold the power button down until the gong for it to boot. If the power button is pressed for a normal press or shorter than 5 seconds, the MacBook will just shut off again. Its like you need to give it plenty of gas to get it started so to speak 🙂

I thought I was making progress, but once I started to diagnose the backlight (armed with previous users experiences in this thread), I was dismayed to find what looks like burnt out pins on the LVDS cable 🙁

I'm afraid this is probably where I have to bow out. Having read earlier that its very hard to take the screens apart, I'm not sure I want to go down that route, especially considering that once the LVDS cable is replaced, its safe to assume there is other damage on the logic board as a result of the burn-out anyway 🙁

I'd just like to say thanks for an amazing thread and its nice to see you are still active and answering people's queries some #1007 posts later!

 

[Dadioh]

Hello i have a Macbook non pro 2008 with no backlight. I messured the smale fuse on the backsite 12.5V, its working. The Power boost diode is on both sides 0 V and the enable signal for the APP001A is 0V. The APP001A should be ok i messured all resistance as showen on the first side.


Any ideas what to check now ?

The enable pin should be 3V. It is a voltage divider of 2 resistors that brings 12V down to 3V. Check those 2 resistors. I suspect one of them is bad.

 

[mousepad]

This picture gives a better idea about where the missing parts are located. I think a schematics might be needed for this for even if one open up the computer see the part but still not knowing what it is.Please help.

Peter

The left one must be an 47 Ohm Resistor (1/8W, housing 804), the right the backlight-fuse (2A, 32V, 302).

 

[gb123]

I have a 13" Late 2008 Unibody MacBook (A1278) with some minor water damage, and the backlight is having issues. In particular, the backlight will not turn on unless I remove the battery, replace the battery, then boot without being plugged into the AC adapter. No other combination seems to do the trick. Moreover, once booted with the backlight, I can safely turn the backlight off by cranking down the brightness and still restore it just as easily, but if I ever let the display shut off via sleep or what have you I need to reboot/remove the battery once again. Given all this, what could be going on? Thanks in advance!

 

[Dadioh]

I have a 13" Late 2008 Unibody MacBook (A1278) with some minor water damage, and the backlight is having issues. In particular, the backlight will not turn on unless I remove the battery, replace the battery, then boot without being plugged into the AC adapter. No other combination seems to do the trick. Moreover, once booted with the backlight, I can safely turn the backlight off by cranking down the brightness and still restore it just as easily, but if I ever let the display shut off via sleep or what have you I need to reboot/remove the battery once again. Given all this, what could be going on? Thanks in advance!

It seems that the WLED (backlight) driver circuit is working since it is able to drive the voltage. From what you are describing it is an SMC issue where it is disabling the backlight for some reason. I am wondering if it is also disabling the display data as well? When the backlight goes off can you see any image using a light shining on the screen? If not, it sounds as if the SMC is completely turning off the whole display, including backlight.

If this is the case then you should be troubleshooting the SMC rather than the WLED driver.

 

[gb123]

It seems that the WLED (backlight) driver circuit is working since it is able to drive the voltage. From what you are describing it is an SMC issue where it is disabling the backlight for some reason. I am wondering if it is also disabling the display data as well? When the backlight goes off can you see any image using a light shining on the screen? If not, it sounds as if the SMC is completely turning off the whole display, including backlight.

If this is the case then you should be troubleshooting the SMC rather than the WLED driver.

I can in fact see such an image. I've had issues in the past related to the backlight (before the water damage) but I think they were largely related to the use of hacks like InsomniaX.

I should add that the amount of time I need to remove the battery to allow it to boot with the backlight is somewhat variable, and moreover resetting the PRAM and SMC do not help.

 

[quietmilk]

First I want to say thank you to Dadioh. I have read much of this entire thread and your knowledge has been very helpful in narrowing down the issue I am having. I thank you in advance for any feedback on my issue:
Very similar to the gb123, except I have had no water damage or any other damage that I know of. The backlight on my My MB Pro A1150 simply stopped working a few weeks ago. Started flickering and then died. Computer works fine with external monitor. I have replaced the entire display and there is an improvement in that the display worked at first, but as soon as I adjusted the brightness - down from full - it started flickering and went dark. Still can see image on screen with a flashlight. If I boot up on battery, AC disconnected, the backlight will come on when I plug in the AC. As long as I don't adjust the brightness, shut down or put the MB to sleep I can use the MB normally. Runs as well as the day I bought it!
I reset the SMC and PRAM already to no effect.
If it is the SMC, how do I troubleshoot that?

 

[amanp]

Macbook Unibody A1342 2009, no backlight

I had to chime in here for anyone else who is trying to find the backlight fuse on a A1342 MacBook. I recently fixed a logic board by following the hints in this thread and others. The fuse is located quite a distance from the WLED driver and has a white dot on it. Here are a few pics with increasing zoom level. The backlight is back... thanks!

Hi fixitgood, I have the Macbook Unibody A1342 2009 with no backlight (works with ext. display)and it seems like you had the exact same thing. I found the fuse as you showed in your pictures and it read in MegaOhms (So, im assuming its blown) I just wanted to ask you if you had any liquid damage too and what fuse did you buy to replace and from where, any other info will be really helpful. Your post gave me hope that maybe if i followed your lead I could fix mine too. 🙂
Thanks to everyone who have shared their experiences and expertise on this thread. Its definitely helped a whole lot of people including me.

 

[Dadioh]

I can in fact see such an image. I've had issues in the past related to the backlight (before the water damage) but I think they were largely related to the use of hacks like InsomniaX.

I should add that the amount of time I need to remove the battery to allow it to boot with the backlight is somewhat variable, and moreover resetting the PRAM and SMC do not help.

Odd indeed. Either the backlight circuit or the SMC seems to be flakey. My guess is the SMC based on the odd influences of battery and magsafe.

----------

First I want to say thank you to Dadioh. I have read much of this entire thread and your knowledge has been very helpful in narrowing down the issue I am having. I thank you in advance for any feedback on my issue:
Very similar to the gb123, except I have had no water damage or any other damage that I know of. The backlight on my My MB Pro A1150 simply stopped working a few weeks ago. Started flickering and then died. Computer works fine with external monitor. I have replaced the entire display and there is an improvement in that the display worked at first, but as soon as I adjusted the brightness - down from full - it started flickering and went dark. Still can see image on screen with a flashlight. If I boot up on battery, AC disconnected, the backlight will come on when I plug in the AC. As long as I don't adjust the brightness, shut down or put the MB to sleep I can use the MB normally. Runs as well as the day I bought it!
I reset the SMC and PRAM already to no effect.
If it is the SMC, how do I troubleshoot that?

A1150 is the original MBP from 2006? If so, that is not an LED backlight. You should be focusing on the inverter that generates the high voltage for the CCFL (Fluorescent tube). Don't really know too much about those.

 

[strikerba]

Dadioh, i hope you're doing this for a living ! You're true Macbook guru !

About my situation, it's still status quo, still waiting for LVDS cable, but i have another question, i have

Macbook Pro, Mid 2010, Core2Duo processor
Macbook Pro, Mid 2011, i5 processor

are their parts interchangeable? screen to be precise ?
the thing is, i have an oportunity to buy that i5 for fairly good price, but it has cracked display, everything else workes fine, i connected it to external display.

It their parts are interchangeable, than i can make an FrankenBook with some spare parts a side 🙂

Thanx heaps guys !

 

[quietmilk]

A1150 is the original MBP from 2006? If so, that is not an LED backlight. You should be focusing on the inverter that generates the high voltage for the CCFL (Fluorescent tube). Don't really know too much about those.

Thanks for your response!
That is indeed the one. Correct, it is a CCFL - I knew that, but I flaked on it for a second. I will look into the inverter! Thanks again!

 

[strikerba]

To post a reply to myself and all others that are asking the same question, l.a.rossmann actually put a great interchangeable post

a) LCD is interchangeable across all A1278 Macbooks & Macbook Pros regardless of year. The 2008 models have poor quality LP133WX2-TLC* series LCDs in them which are not typically found in newer models.

You can find more here

https://forums.macrumors.com/threads/1369004/

 

[Dadioh]

To post a reply to myself and all others that are asking the same question, l.a.rossmann actually put a great interchangeable post

a) LCD is interchangeable across all A1278 Macbooks & Macbook Pros regardless of year. The 2008 models have poor quality LP133WX2-TLC* series LCDs in them which are not typically found in newer models.

You can find more here

https://forums.macrumors.com/threads/1369004/

The 2008 A1278 also has the magnet on the other side of the screen so if you want it to sleep when you close the lid you will need the correct display. Or you can glue a fridge magnet to the other side 😀

The 2009 and 2010 are directly interchangeable. The 2011 has different setup for wifi and Bluetooth cables so I don't think you can interchange 2009/2010 with the 2011.

 

[strikerba]

The 2008 A1278 also has the magnet on the other side of the screen so if you want it to sleep when you close the lid you will need the correct display. Or you can glue a fridge magnet to the other side 😀

The 2009 and 2010 are directly interchangeable. The 2011 has different setup for wifi and Bluetooth cables so I don't think you can interchange 2009/2010 with the 2011.

At this moment, i just need to replace the screen, so i think that'll do it. Love the fridge magnet suggestion 😀

 

[amanp]

The 2008 A1278 also has the magnet on the other side of the screen so if you want it to sleep when you close the lid you will need the correct display. Or you can glue a fridge magnet to the other side 😀

The 2009 and 2010 are directly interchangeable. The 2011 has different setup for wifi and Bluetooth cables so I don't think you can interchange 2009/2010 with the 2011.

Hi Dadioh,
First of all, thanks to your expertise and help that many motherboards escaped the landfill. This is a great thread and has helped a lot of people.
I asked ifixitgood about the procedure he followed but I haven't gotten a reply yet. I was wondering if you knew about the part I need to buy. I have the exact same motherboard as in these pics (https://forums.macrumors.com/posts/16165131/)
its a Macbook unibody A1342 (non-pro).
and where should I buy it from, I saw your links and other links in this thread (Digikey and others) but just asking if anything has changed about your opinion of the source to get the part from. I checked the resistance across the fuse and it is in megaohms and so I assumed it blown, Is that right?

Thanks again

 

[Dadioh]

Hi Dadioh,
First of all, thanks to your expertise and help that many motherboards escaped the landfill. This is a great thread and has helped a lot of people.
I asked ifixitgood about the procedure he followed but I haven't gotten a reply yet. I was wondering if you knew about the part I need to buy. I have the exact same motherboard as in these pics (https://forums.macrumors.com/posts/16165131/)
its a Macbook unibody A1342 (non-pro).
and where should I buy it from, I saw your links and other links in this thread (Digikey and others) but just asking if anything has changed about your opinion of the source to get the part from. I checked the resistance across the fuse and it is in megaohms and so I assumed it blown, Is that right?

Thanks again

That would be the same fuse as used on the other 13" unibody models. 0402 size. 2 Amp. Digikey or Newark are the sources I usually use. You could use the link I provided earlier in the thread.

Good luck.

 

[amanp]

That would be the same fuse as used on the other 13" unibody models. 0402 size. 2 Amp. Digikey or Newark are the sources I usually use. You could use the link I provided earlier in the thread.

Good luck.

Thanks Dadioh,
I will try that and report back when Im done.

 

[strikerba]

That would be it. Pin 1 is ground but pin 2 and 3 are the 3.3V power to the LCD panel. Without that the LCD will not display anything. In fact it may not even turn on the backlight because there may be feedback to the SMC that the display is not working so do not bother turning n the backlight.

I just remembered to check system profiler, heres what it says about internal display

Color LCD:
Resolution: 1280 x 800
Pixel Depth: 32-Bit Color (ARGB8888)
Mirror: On
Mirror Status: Hardware Mirror
Online: Yes
Built-In: Yes

😡 im getting pis.... with this mac, what can this mean ?

 

[Musicsoul78]

UPDATE:

Maybe it's time to contribute a little on this large forum 😉 I found the WLED driver on MID 2009 Macbook pro 820-2530-A, I included the picture and location of it. I also include the link from Digikey with the part number. However I am still unable to locate the WLED drivers on the 2 x MacBook Pro (13-inch, Early 2011) -#820-2936-A. Any help would be great.

Image

i have the same issue as you pal 820-2936

quick question

found braking fuse and i replaced

also repalced wled driver

still same issue no backlight

is there a 3rd device eg a fuse that can be replaced (not the one with a p on)

many thanks

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I just remembered to check system profiler, heres what it says about internal display

Color LCD:
Resolution: 1280 x 800
Pixel Depth: 32-Bit Color (ARGB8888)
Mirror: On
Mirror Status: Hardware Mirror
Online: Yes
Built-In: Yes

😡 im getting pis.... with this mac, what can this mean ?

are you viewing this info from an external monitor???

----------

Some fuses (depending on manufacturer) may not have a dot but a letter code that describe it's current limit rating. The one marked in the attachment maybe the fuse you're searching for. A "P" I believed maybe an indication that it is a 3A rated fuse.

mr data is this the same 3a rated fuse??

http://uk.farnell.com/multicomp/mcsef-u-003/fuse-smd-3a/dp/1841088

saves me using donor boards

many thanks