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MacBook Pro Unibody - No Backlight - Logic Board Question

Macbook pro corei5 early 2011, no backlight

How about Dadioh friend, can you help me? I have a macbook pro early 2011, no backlight, it fell soda, when turned on flashes for a moment and it is not only closer but a flashlight, you connect an external monitor and you see no problem, could you please tell me what are the components to review? I have a multimeter. thank you, I hope your answer. Greetings!
 
Loomingx said:
I have a Macbook A1260 with no backlight. I have replaced the entire LCD assembly/inverter board to confirm that this is a mainboard issue. From what I've read in this thread this is most likely a blown fuse. I have tested some fuses that I have been able to see but I'm sure i've missed a few. Is there any way someone can show me which fuse generally needs to be replaced on a A1260 model? I've seen that the F9800 is generally the issue but I can't find it for the life of me!
Click to expand...

I've got a bit of experience on the pre-unibody boards.

The one you've shown is the "late 08" or 2.2/2.4 MBP family group.

the backlight power for this unit is very different than all the Unibody series.

The backlight power is fed directly off the Left I/O board, in a 4 pin connector which plugs in at the top edge of the left I/O board (the left PCB in the laptop, which has the Magsafe connector)... There is only 1 4-pin connector from the LCD into that board--that's the one.

I've rebuilt 400-500 of these series, and have NEVER seen the backlight fail due to a logic board/chip issue.. it's almost always been the LED driver board (another item unique to that unit system) which sits under the LCD, somewhat like the backlight inverter board in the older Macbook Pro series...

i'd check voltage going into that board, and if it's got voltage, replace it....
 
Dadioh said:
I think it is the device shown in my picture but to be sure can you read the part number off the top for me?

Also, can you get closeups of the front and back at this location (beside the LVDS connector) and around this device on the back so I can help you find the fuse.
Click to expand...

Thanks for your answer Dadioh, and sorry for my late reply. The number on the chip is "VM09AC 45 EXTF" (the "5" might be an "S", and the "T" might be an "I", but I am pretty sure I got it right)

Here is the the pictures you was asking for. I have taken the photos with my 4S, and I can't really take them any closer without loosing focus. If you need them better, I can take pics with a real camera. Let me know.

http://photobucket.com/mbp17a1297wled
 
Hello all,

I have MBP 13" 2010 A1278 unibody into which few drops of Coke splashed.
Result is, that MBP does not start, it tries to start then shuts down and it's doing this indefinitelly. I get no screen output nor backlight.

I have measured 2A fuse (with the dot) and it was blown. Tried to replace it, however, during replacement new fuse blew out as well.

I've afterwards connected (by touching pads where fuse was located) my current load instead of fuse and limited current to 1.5A.
Current drawn went up to 1.5A after start and stayed there.
After starting MBP, I've touched parts on board and part next to the fuse marked DP is overheating.

Do You know what part number DP is?
Layout is similar to the one on comment #99, apart I don't have that white part next to L8454 and parts are layed out differently...

EDIT1: I've searched and smd part marked with DPhttp://clivetec.0catch.com/SMD_CodesD.htm should be MMBD2010 which is dual cc MMBD2000. Can't find this part so far...
 
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Macbook A1342, Backlight blinks for 1 second on start up then remains off. Help

Hi All, my first time on this forum.
I must say amazing to see all the helpful support and guidance. I am in a dilema and need your help.

Earlier around page 8 of this someone posed the same diagnosis as mine however no one replied to that post.

My Mac A1342 fully functions however backlight does not work. I cleaned the liquid damage (coffee) from the board. There wasn't alot but enough to prevent power circulation and shorts. It attempts to start the backlight on power up for a spilt second but after something prevents this (SMC deactivating it?):eek: So gives display but dark.

I have tested:
=The fuse an inch away from the LVDS connector and shows 12v solid both sides so I believe this is perfectly fine.

Thank you.

PS - now it refuses to give a display at all :( help please
 
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Hi all, new to this thread. I have recently purchased a late 2008 (the first unibody) macbook pro. The backlight for it has gone out- it came without a display assembly, but I found one and slapped it on. Alls well, but no backlight. soo

1. Where is the fuse for this model (A1286 Late 08/Early09) so I can check if it is blown. On thursday I will be reseating/aligning the keyboard backlight and have to take the logic board out.... so I might as well check.

2. How can I tell if it is the fuse that has blown, or if it is the WLED driver?

3. Is it safe to boot it up while shorting out the fuse (assuming it was blown)? Will this cause a surge to my WLED?

Edit: also... something strange... Liquid was spilled in the right of the keyboard, but the backlight went out.... The LDVS is on the opposite side. What could be funny there?

4. If it was that... could I just short the contacts and run it (bad Idea....)? Note that I am pretty nice to electronics, and only got water near a macbook once (near the vents) and immediately shut it off. It didnt even get wet :)

Anyways, awaiting replies. Thanks in advance

-Thomas
 
joccolai said:
Thanks for your answer Dadioh, and sorry for my late reply. The number on the chip is "VM09AC 45 EXTF" (the "5" might be an "S", and the "T" might be an "I", but I am pretty sure I got it right)

Here is the the pictures you was asking for. I have taken the photos with my 4S, and I can't really take them any closer without loosing focus. If you need them better, I can take pics with a real camera. Let me know.

http://photobucket.com/mbp17a1297wled
Click to expand...

Sorry for the late reply. Busy busy busy.

Anyway, see attachments for location of your fuse and WLED driver.
 

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aleds1234 said:
How about Dadioh friend, can you help me? I have a macbook pro early 2011, no backlight, it fell soda, when turned on flashes for a moment and it is not only closer but a flashlight, you connect an external monitor and you see no problem, could you please tell me what are the components to review? I have a multimeter. thank you, I hope your answer. Greetings!
Click to expand...

I have never looked at a 2011 MBP but I assume the design is similar to 2009 or 2010. Have a look at fuse location for 2009 earlier in thread and see if yours is the same.

----------
aqibi2000 said:
Hi All, my first time on this forum.
I must say amazing to see all the helpful support and guidance. I am in a dilema and need your help.

Earlier around page 8 of this someone posed the same diagnosis as mine however no one replied to that post.

My Mac A1342 fully functions however backlight does not work. I cleaned the liquid damage (coffee) from the board. There wasn't alot but enough to prevent power circulation and shorts. It attempts to start the backlight on power up for a spilt second but after something prevents this (SMC deactivating it?):eek: So gives display but dark.

I have tested:
=The fuse an inch away from the LVDS connector and shows 12v solid both sides so I believe this is perfectly fine.

Thank you.

PS - now it refuses to give a display at all :( help please
Click to expand...

Even though the fuse is good it sounds like the WLED driver is detecting too much current and is shutting off the backlight. I would focus on the WLED driver circuit itself.

----------
astroboy907 said:
Hi all, new to this thread. I have recently purchased a late 2008 (the first unibody) macbook pro. The backlight for it has gone out- it came without a display assembly, but I found one and slapped it on. Alls well, but no backlight. soo

1. Where is the fuse for this model (A1286 Late 08/Early09) so I can check if it is blown. On thursday I will be reseating/aligning the keyboard backlight and have to take the logic board out.... so I might as well check.

2. How can I tell if it is the fuse that has blown, or if it is the WLED driver?

3. Is it safe to boot it up while shorting out the fuse (assuming it was blown)? Will this cause a surge to my WLED?

Edit: also... something strange... Liquid was spilled in the right of the keyboard, but the backlight went out.... The LDVS is on the opposite side. What could be funny there?

4. If it was that... could I just short the contacts and run it (bad Idea....)? Note that I am pretty nice to electronics, and only got water near a macbook once (near the vents) and immediately shut it off. It didnt even get wet :)

Anyways, awaiting replies. Thanks in advance

-Thomas
Click to expand...

I don't have any of the 2008 MBP15" unibody logic boards to check but you will be looking for a fuse similar to the other pictures available on here. I am guessing it is on the back side of the logic board opposite where the LVDS connector is located. Look for a small beige device with a dot. Measure it with a meter (with no power on the board) and check the resistance across the fuse. Should be close to zero ohms. High ohms means it is blown.
 
Macbook pro corei5 early 2011, no backlight

Thank you very much for the reply Dadioh with a multimeter check the fuse with a letter "p" above, and brand continuity, and 0.3 ohms. I guess it's okay, I just need to know what the chip WLED not find it worth mentioning that when turned on gives a flash of light on and off, to which it should? thanks greetings! :confused:
 
dervmonkey said:
I'm trying to decide wether to spend my money on a reasonable hot air station and magnifying gear, along with the WLED driver IC - I'm a pretty competent guy with regards fixing stuff - the only stumbling block is the availability of the LP8543 in the UK - Farnell (I think) show as having stock, but in the Newark (NJ?) warehouse and want £16 to transfer stock to the UK, the IC itself is listed as under £3

Does anyone know of a UK stockist of the WLED IC?
Click to expand...

It looks like Digi-Key may not ship this IC to me for some unknown reason, they've taken 6 days since I ordered to start asking questions like which company I work for, websites for the company I work for and what I plan on doing with such an IC, should they deem to sell it to me.

So, does anyone know of a UK stockist of an LP8543 so I can fix my MacBook Pro?
 
Help 1278 no image only light

i have a 13.3 mac 1278 2.4ghz.
my display not work and i go to someone to change.
wrong display and i don't have no light...even first display nothing apear

i change the fuse and light appear i have 27v at rezistor 125 but no image only light !!!

before i change the fuse i use laptop on external monitor...now not work on external...only light on internal

what happening?
the display driver is 20 pin APP_1A

someoane can give me a 20 pin APP001 i don-t find datasheet of this 2 pieces to compare

please help...what mesurement to do to find problem with no image only light??!!

my english.....
 
Hello Dadioh. I saw that you replied to some of the posts here, but maybe you didn't see my post, because it's on the previous page. Could you please take a look at the pictures and the measured values?

Thank you in advance!

P.s. see previous page for the high res picture.



Mikf said:
Hi all!

Yesterday i bought a Macbook pro mid 2009 (2,66GHz, 15,4") with a non working backlight. The screen is showing picture.

I read some posts in this forum threat and i decided to get the logic board out. I measured some points, i hope you guys can point me in the right direction.

Here is my logicboard:
[url=http://www.freebits.nl/images/348macbook_pro_tn.jpg]Image[/URL]

Here are the measured values:
1: Some resistance .000
2: Some resistance .000
3: 0.300
4: Nothing 1.

So I guess my fuse is blown, am I right? Are the other values good?

Thank you in advance. And sorry for the bad English, I'm from Holland.

-Edit- Is this the fuse to get?
Click to expand...
 
@Dadioh

do You have schema available for A1278 Macbook pro 2010?
Fuse blowns after replacing, so there is short somewhere... maybe LP8545 gone or something.
 
Ok, found my fuse- its directly below the end of the arrow in this pic (http://i53.tinypic.com/2n8txn4.png)

So a few questions. Basically I am going to order the fuse before I test it, so I dont have to tear down the whole laptop twice.

1. What voltages are the fuses? I assume 32v is the correct one I am looking for
2. What speed fuse do I get? Not a slow burning, but between fast acting and very fast acting.
3. Its a 2A fuse, correct? Just making sure :)

This is just for me, but I was wondering if you knew if it was mostly fuses burning out, or more likely the WLED driver... If it is the fuse I am 90% confident I can solder in a new one, but if it is an IC I am a bit more wary.


EDIT: What is this about the fuse being a high freq. cap? Posted on 1st post.
 
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Test WLED driver on MBP 13 Early 2011 A1278

I have a MBP 13 early 2011 (A1278) and need some help testing the WLED driver. I read most of these threads which were referring to pin layout for older models. I have seen Dadioh posting some instructions on how to measure and test it which is measure resistance to ground for each pin.

I have Fluke DIMM and very fine probes with the scope so precision is not an issue here. I just want to make sure i'm doing it right, so touch one pin with one probe and the other touch to the ground pin of the WLED driver or just the ground in general like the metal part of the MOBO top right corner.

Next, the fuse. I located two fuses with no problem using schematic white tinny SM, now i can't get any voltage on it either with battery connected or not. Folks are reporting 12V or 27V, not sure why my reads 0V - BTW this is a working logic board that powers on and everything works, i'm just playing with it and comparing to the one that was water damaged. Continuity test is fine beeps and the resistance is very low 0-0.2 Ohm

I attached the diagram of the WLED chip which is part LP8550
 

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Mikf said:
Hi all!

Yesterday i bought a Macbook pro mid 2009 (2,66GHz, 15,4") with a non working backlight. The screen is showing picture.

I read some posts in this forum threat and i decided to get the logic board out. I measured some points, i hope you guys can point me in the right direction.

Here is my logicboard:
[url=http://www.freebits.nl/images/348macbook_pro_tn.jpg]Image[/URL]

Here are the measured values:
1: Some resistance .000
2: Some resistance .000
3: 0.300
4: Nothing 1.

So I guess my fuse is blown, am I right? Are the other values good?

Thank you in advance. And sorry for the bad English, I'm from Holland.

-Edit- Is this the fuse to get?
Click to expand...

Looks like fuse is blown assuming that "nothing" means large resistance (Megaohms)

That fuse that you linked will work.

----------
aqibi2000 said:
Dadioh can you please please assist me post Number 606. Thank youuu
Click to expand...

Hi. I don't have any experience with the A1342 so I hadn't responded. Also, that model uses a different backlight driver from the aluminum unibodies. But from what you describe that backlight driver is detecting a problem... probably over current, and shutting itself off. You will need to troubleshoot that circuit but I am not the right one to help. Sorry.

----------
U-234 said:
I have a MBP 13 early 2011 (A1278) and need some help testing the WLED driver. I read most of these threads which were referring to pin layout for older models. I have seen Dadioh posting some instructions on how to measure and test it which is measure resistance to ground for each pin.

I have Fluke DIMM and very fine probes with the scope so precision is not an issue here. I just want to make sure i'm doing it right, so touch one pin with one probe and the other touch to the ground pin of the WLED driver or just the ground in general like the metal part of the MOBO top right corner.

Next, the fuse. I located two fuses with no problem using schematic white tinny SM, now i can't get any voltage on it either with battery connected or not. Folks are reporting 12V or 27V, not sure why my reads 0V - BTW this is a working logic board that powers on and everything works, i'm just playing with it and comparing to the one that was water damaged. Continuity test is fine beeps and the resistance is very low 0-0.2 Ohm

I attached the diagram of the WLED chip which is part LP8550
Click to expand...

That is the correct method. I am measuring the impedance of each pin to ground. You can use any ground on the board. I usually use one of the screw holes. The intent is to see if something inside the device has been damaged. When that happens it will usually be detectable by a change in the impedance to ground.

By the way I use the word impedance and resistance interchangeably here in this thread. Technically resistance is what we are measuring with a multimeter. Impedance includes resistive, inductive, capacitive elements but we are not measuring those.

The fuse should have 12V on it since it is 12V that is powering the WLED driver. The 27V is what the WLED driver boosts the voltage to in order to drive the LED's in the display. That 27V is typically measured either at the diode (if accessible) or at the LVDS connector (if there is a safe place to do it without shorting something).

----------
rasto said:
@Dadioh

do You have schema available for A1278 Macbook pro 2010?
Fuse blowns after replacing, so there is short somewhere... maybe LP8545 gone or something.
Click to expand...

I can't PM or email you yet. You may need more posts to enable that.

----------
astroboy907 said:
Ok, found my fuse- its directly below the end of the arrow in this pic (http://i53.tinypic.com/2n8txn4.png)

So a few questions. Basically I am going to order the fuse before I test it, so I dont have to tear down the whole laptop twice.

1. What voltages are the fuses? I assume 32v is the correct one I am looking for
2. What speed fuse do I get? Not a slow burning, but between fast acting and very fast acting.
3. Its a 2A fuse, correct? Just making sure :)

This is just for me, but I was wondering if you knew if it was mostly fuses burning out, or more likely the WLED driver... If it is the fuse I am 90% confident I can solder in a new one, but if it is an IC I am a bit more wary.


EDIT: What is this about the fuse being a high freq. cap? Posted on 1st post.
Click to expand...

The fuse sees 12V nominal so 32V is plenty. Get fast acting variety. It is a 2A fuse.

On the first post I was new to the whole thing and was wondering if the white device was a fuse. It turns out that it is NOT a fuse. It is a 200pF capacitor on the backlight output. Replacing it with a fuse would be a big mistake.

----------
babyboo said:
I need help. I have a 2010 macbook pro 13 has been water spill and some parts are smoke. can anyone tell me where can i buy those red arrow parts. Thanks

http://www.mediafire.com/download.php?1muub8v365epbqr
http://www.mediafire.com/download.php?7o8g9gbq4jwa1jv
Click to expand...

The green part is the current sensing resistor for the battery charger output. The 5 pin device is the FET that controls whether to send power to the battery. The yellow and black devices are capacitors. You need to read the part numbers off the devices and google them. I use Digikey here in Canada.
 
Dadioh said:
Further back in the thread are the measurements for the WLED driver pins resistance to ground. You should measure each pin to ground and compare to the tables. That will help narrow down the problem.
Click to expand...

Thank you Dadioh for your help.

But I can't find the WLED driver on my board and which measurements must have the pins. I didn´t find the thread, too.Perhaps you can post the Link?! Can you write me an Email with introductions to fa.schaefferer@web.de? I'm really sorry, but can you help me step by step. I´m a poor student who needs his MacBook.

Ps.: I've got a MacBook A1278
Thank you so much

insider_la
 
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astroboy907 said:
Ok, found my fuse- its directly below the end of the arrow in this pic (http://i53.tinypic.com/2n8txn4.png)

So a few questions. Basically I am going to order the fuse before I test it, so I dont have to tear down the whole laptop twice.

1. What voltages are the fuses? I assume 32v is the correct one I am looking for
2. What speed fuse do I get? Not a slow burning, but between fast acting and very fast acting.
3. Its a 2A fuse, correct? Just making sure :)

This is just for me, but I was wondering if you knew if it was mostly fuses burning out, or more likely the WLED driver... If it is the fuse I am 90% confident I can solder in a new one, but if it is an IC I am a bit more wary.


EDIT: What is this about the fuse being a high freq. cap? Posted on 1st post.
Click to expand...

That is a capacitor. NOT a fuse. Replace that with a fuse or short circuit it and you've ruined your logic board. I wouldn't be attempting such repairs unless you know what your doing on an analysis level.
 
insiderla said:
Thank you Dadioh for your help.

But I can't find the WLED driver on my board and which measurements must have the pins. I didn´t find the thread, too.Perhaps you can post the Link?! Can you write me an Email with introductions to fa.schaefferer@web.de? I'm really sorry, but can you help me step by step. I´m a poor student who needs his MacBook.

Ps.: I've got a MacBook A1278
Thank you so much

insider_la
Click to expand...

Please help me!
 
Macman756 said:
That is a capacitor. NOT a fuse. Replace that with a fuse or short circuit it and you've ruined your logic board. I wouldn't be attempting such repairs unless you know what your doing on an analysis level.
Click to expand...

I know the arrow is pointing to a cap- its just a leftover from a previous forum post. The part I am replacing is the tiny 0402 with a dot, directly below the "butt" of the arrow.
 
So, my 15" mid-2009 Macbook Pro (2.8GHz CTO, A1286) suffered a spill. I broke it down, bathed a bunch of components in 99% isopropyl alcohol and cleaned everything I could up, let it dry and now it's booting again. Aside from the keyboard being screwed up (have a replacement on the way), my display is screwy. The backlight does work, however it's only bright at the bottom. The upper 75% of the screen is dark and blotchy. Is this likely just a LCD panel that needs replaced, or potentially something going on with the LED driver on the logic board or LVDS cable? I'm hoping I'll be able to survive this with a straightforward LCD replacement (actually using this as an opportunity to upgrade to the higher-res panel!), but I don't want to do that until I'm sure I understand the backlight and what really is broken.

How does the backlight work, exactly? Is there just one row at the bottom that should diffuse evenly across the entire display? Are there multiple rows?

Attached is what the display looks like. Hoping someone recognizes this type of issue.

I must admit I did stick it in a 170 degree oven (as low as it would go) for a few minutes to warm it up and convince myself things were dry before I turned it on the first time, without the logic board or battery inside. I figured 170 degrees was something these components are able to handle. I think that didn't ruin anything... but it's possible heat damage is also a factor. :-/ Safe to assume some alcohol got up inside the display assembly too.
 

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