MacBook Pro Unibody - No Backlight - Logic Board Question

[cpufixer]

does anybody want to fix this for me, I just do not have the right tools right now..

EDIT: this works ok on external display, also noticed keyboard backlight is not working..

By the way, It looks like I finally fixed my 13 mbp with the backlight problem, there was corrosion buildup near the white cap at the battery connector, effecting a dime size around it and some nearby components. Fixed last night, still keeping fingers crossed. has not happened after fix.

hi again guys, here is a up date, did some resistance testing on the backlight components and everything checked out good, just re soldered the fuse, and walla, light....still no keypad light...where do I start looking?

the 13 inch backlight still no fix, worked good for 2 days, then no light.
the only way to get it on is to disconnect the battery...weird,....

EDIT: 13 inch, tried running it with battery disconnected, still it will sometimes not have a backlight when waking up from sleep or restart, disconnecting power is only way to get backlight. Anybody know where to start testing for this...

 

[cpufixer]

just some pics,

let me know what you think guys, does it look fixable?

 

[etypecie]

A1278 820-3115-b

Hello.
You're doing great job here!
I would like if you could help me too.
I have Macbook A1278 with 820-3115-B motherboard after water damage.
There is no backlight of screen (flashlight trick works) and keyboard. I check voltage :
I2C_BKL_1_SCL 3,3V at R9753
I2C_BKL_1_SDA 3,3V at R9757
LCD_BKLT_PWM 3,3V at R9704
PP3V3_S0_BKL_VDDIO 3,3V at C9711
PPBUS_SW_BKL 12,4V at C9712
PP5V_S0_BKL 5V at C9710 and C9714
PPBUS_S0_LCDBKLT_FUSED 12,4V at F9700 and on out Q9706
PP3V3_S0_LCD 3,3V at R9008 and R9009
PP3V3_LCDVDD_SW 3,3V at L9004
PPVOUT_SW_LCDBKLT 12,4V at C9020
PPBUS_SW_LCDBKLT_PWD 12,4V at R0910 and then 3,06V at R9715
and there it 0V at BKL_ISEN1,..,BKL_ISEN6, so this is mean that U9701 need to be replace?

Albo Magsafe works 1 on 5-10 tries. I have to plug it slowly and then there is green light and it starts (no battery inside).

Please help me with backlight and connector.
Thanks in advance.
PS: Sorry for my english.

 

[mAchatronicsEng]

U9701 may infact be dead. Which WLED driver do you have? Read the part number off the U9701. With power disconnected check the resistance of each pin to ground and report back.

Hello.
You're doing great job here!
I would like if you could help me too.
I have Macbook A1278 with 820-3115-B motherboard after water damage.
There is no backlight of screen (flashlight trick works) and keyboard. I check voltage :
I2C_BKL_1_SCL 3,3V at R9753
I2C_BKL_1_SDA 3,3V at R9757
LCD_BKLT_PWM 3,3V at R9704
PP3V3_S0_BKL_VDDIO 3,3V at C9711
PPBUS_SW_BKL 12,4V at C9712
PP5V_S0_BKL 5V at C9710 and C9714
PPBUS_S0_LCDBKLT_FUSED 12,4V at F9700 and on out Q9706
PP3V3_S0_LCD 3,3V at R9008 and R9009
PP3V3_LCDVDD_SW 3,3V at L9004
PPVOUT_SW_LCDBKLT 12,4V at C9020
PPBUS_SW_LCDBKLT_PWD 12,4V at R0910 and then 3,06V at R9715
and there it 0V at BKL_ISEN1,..,BKL_ISEN6, so this is mean that U9701 need to be replace?

Albo Magsafe works 1 on 5-10 tries. I have to plug it slowly and then there is green light and it starts (no battery inside).

Please help me with backlight and connector.
Thanks in advance.
PS: Sorry for my english.

----------

let me know what you think guys, does it look fixable?

Your LVDS connector looks jacked. I can tell from the pics if the traces are pulled up. If they are it till should be fixable, just means more work.

 

[macrepair]

I have a MacBook Pro Retina A1398 with no backlight after spillage. I found the fuse was blown so replaced but blew again. I think this may be a faulty WLED driver but not 100% sure I'm looking at the correct part and unable to determine the part number. I believe the logo is National Semiconductor and it reads VM24AP 45-EXTJ. Any help with determining if this is the WLED driver correct part number would be greatly appreciated.

 

[etypecie]

820-3115-b water damage

U9701 may infact be dead. Which WLED driver do you have? Read the part number off the U9701. With power disconnected check the resistance of each pin to ground and report back.

Lp8550 probably, I'll check later. I have to unsolder it to check the resistance, right?

 

[cpufixer]

Check the soldered joint on the component marked "N" or "Z", it doesn't look as though it is soldered properly on the side nearest the 6 pin chip.

Barney

Hi guys, wishing you a good morning,
I re-soldered the fuse and now backlight is working, but keyboard backlight is not, no power at keyboard backlight jack(300mv), it was working before, is there a fuse for key back light?

EDIT: can the keyboard back light run on 300 mv? I checked the wire and looks like it is broken, does this wire break this easy? zero ohms across the wire points...

 

[cpufixer]

wled driver test lp8543

hi guys, I did some resistance testing on WLED driver, here is what I got, this is on the macbook pro 1278 13 that does not wake from sleep sometimes...have to remove power.

1 0
2 1k
3 115k
4 84k
5 .5
7 6m
8 13k
10 15k
11 15k
15 .5
22 190k
23 1.420m
24 1.31m

 

[mAchatronicsEng]

You need to be more specific on the model. A1278 covers a lot of different machines. Which number do you have. More speciffically look back a couple of pages and you will find the resistance for WLED Drivers. Not sure mine are correct as no one has posted a reply to the resistances.

hi guys, I did some resistance testing on WLED driver, here is what I got, this is on the macbook pro 1278 13 that does not wake from sleep sometimes...have to remove power.

1 0
2 1k
3 115k
4 84k
5 .5
7 6m
8 13k
10 15k
11 15k
15 .5
22 190k
23 1.420m
24 1.31m

 

[cpufixer]

You need to be more specific on the model. A1278 covers a lot of different machines. Which number do you have. More speciffically look back a couple of pages and you will find the resistance for WLED Drivers. Not sure mine are correct as no one has posted a reply to the resistances.

hi, this is a 820-2530-A logic board. Using the reference on page 1...

 

[felixdkat]

I found it just PM me with your email and I will send it to you.

https://forums.macrumors.com/showthread.php?p=19133349#post19133349

tswartfiguer:

did you ever find the boardview file for the 820-2523-B board view?

 

[cpufixer]

hi guys, on the 1278 , 2530...backlight issue where I have to remove power, happens only sometimes(when I need it the most), I can see there is a cap missing, I have two boards like this , it is a .1uf cap. is yours missing too?

 

[tswartfiguer]

https://forums.macrumors.com/showthread.php?p=19133349#post19133349

tswartfiguer:

did you ever find the boardview file for the 820-2523-B board view?

I do have that file if you need it let me know, that file I can share because I had it before I joined an elite private forum that has more files than you could ever imagine.

If anyone wants to join a real repair forum where there is no guess work PM me for the details, there is a membership fee involved but I guarantee you will get that back in the first repair or the money you save on your repair cost. Plus they have a ton of files on an FTP like training and tons of other informational files and videos, for all makes and model computers, its really cool. Took me from a Zero to a hero in no time.

 

[lisambp]

No backlight

Hey all,

I have the no backlight problem on a Sep 2013 purchased ( late 2012 model) Macbook Pro 13" (A1278 I think). I can see the screen with a flashlight and the machine works fine with external monitor. Apple say that a small quantity of liquid (a drop?) must have gotten into the machine because there was a short on the pins that connect the logicoboard to the screen and a tiny tiny amount of corrosion (which I they could only see under magnification..and I cannot see clearly).

So even though this machine is less than a year old and under full Applecare, this is not covered. Repair bill from Apple is $920 (to replace everything.. they don't bother doing much diagnostic work)

So, I now need to figure out how to get it fixed and I wanted to do some self diagnosis. I have been doing a lot of reading and I understand that it could be a fuse, or the WLED driver (If I have one.. I think I have the last non-retina model). I am not sure if I can visually check the fuse or if I need to use a multimeter. I had a look at the components under magnification (see attached pics) and noticed the following:

1. Pin number 10 of the connector seem to be totally severed (see enlarged pic). I cleaned it up with some 99% isopropyl alcohol and a Q-tip
2. There is a white rectangle thing (red circle on main pic) and mine looks a little different to other peoples (others have a green top with an 'R', mine is just white with a rectangular indent on top)

Does anyone know if the severed pin #10 might be the only problem and if so, can a skilled electronics person solder it fixed? Could I easily check this by somehow temporarily bridging that pin (it is VERY tiny so not sure how I would do even that.. is it risky since it may be carrying a higer voltage?)

I have a quote of around $100-300 from one repair place but they didn't do much dianostic work other than briefly glance at it.

Any advice would be greatly appreciated.

 

[lisambp]

Hey all,

I have the no backlight problem on a Sep 2013 purchased ( late 2012 model) Macbook Pro 13" (A1278 I think).

I found the 30pin connector on Amazon for $4 + shipping (http://georiot.co/30q1)

Now how to find a skilled electronics solderer person? and how much should they charge to fit the connector? and should I order the fuse and WLED driver all at once just to cover my bases?

Thank you.

 

[KrsutyCheerio]

I have a left palm sensor error. Where is it located on a early 2011 MacBook pro?

 

[KhawarAshraf]

Macbook Pro Retina (mid 2012) A1398

Hello,

I was cleaning my macbook pro and in the middle of it, it turned on and i did not realized it.

After cleaning i was just using it and few minutes later the backlight went out. I immediately turned it off dried it with heat gun but backlight never came back. I opened it up and took the mother board out, none of the water damage sensor is triggered and i looked it under microscope and i cannot find any water damage.

So, i'm a bit lost here, i read the thread and was wondering if anyone can tell me the location of backlight fuse on this model so that i can test if it is burned or not.

Thanks,
Khawar

 

[fhturner]

So, i'm a bit lost here, i read the thread and was wondering if anyone can tell me the location of backlight fuse on this model so that i can test if it is burned or not.

I'm working on the same issue w/ mine:

http://www.ifixit.com/Answers/View/...nd+type+is+the+same+for+a+Mid-2012+Retina+15"

Here's an image showing the fuse location:

http://d3nevzfk7ii3be.cloudfront.net/igi/UBF2bacANQZTMDGd

 

[kreliz]

Glad to report that another MBP (15" A1286 mid 2012) has been saved from the trash. It was given to me by a friend after it had beer spilled over it. I had the LVDS connector on the LB replaced by a professional. I changed the LVDS cable myself (both got damaged by the spill). I also replaced the fuse myself. I have little to no experience in soldering so i went with another option. Instead of removing the old one and soldering a new in place, i used circuitwriter ink to glue a new one on top of the old one, piggybacking so to speak. Worked like a charm.

So thanks to everybody contributing here and, of course, especially to Dadioh. Great thing you started here.

On a side note, though im happy it works at all, it doesnt run of the battery. I have replaced the magsafe dc-in board and battery. Yet still "no battery available". It was a longshot that cost me some money. I wouldn't mind getting my hands dirty again so if someone has some pointers or feels like diving into this problem, let me know.

 

[Dadioh]

Glad to report that another MBP (15" A1286 mid 2012) has been saved from the trash. It was given to me by a friend after it had beer spilled over it. I had the LVDS connector on the LB replaced by a professional. I changed the LVDS cable myself (both got damaged by the spill). I also replaced the fuse myself. I have little to no experience in soldering so i went with another option. Instead of removing the old one and soldering a new in place, i used circuitwriter ink to glue a new one on top of the old one, piggybacking so to speak. Worked like a charm.

Image​

So thanks to everybody contributing here and, of course, especially to Dadioh. Great thing you started here.

On a side note, though im happy it works at all, it doesnt run of the battery. I have replaced the magsafe dc-in board and battery. Yet still "no battery available". It was a longshot that cost me some money. I wouldn't mind getting my hands dirty again so if someone has some pointers or feels like diving into this problem, let me know.

Clever use of conductive ink. Never used it before so I hope it is reliable over time. At least you know where to start if it were to fail again

The fact that it does not detect battery even after replacing with new one means that the SMC (System Management Controller) is not communicating with the battery. This has nothing to do with the DC-in board in case anyone reading is in the same circumstance.

There is an I2C (pronounced Eye Squared See) serial communications bus that the SMC, charger ISL6259, and Battery use to communicate with each other. These signals are easiest to access at the battery connector. They would be pins 4 and 6. When the MacBook is on you should see 3.4V on these lines. With the macbook is turned off and battery disconnected you can also measure resistance of these pins to ground to make sure they are not shorted.

If you follow the I2C around the schematic you can see how it communicates between the SMC, charger, and battery. In your case this bus is not working. Possible causes:

1) D6950 shorted to ground. If you measure a low voltage on the lines (not 3.4V) this could be the cause.
2) C6953 and/or C6952 shorted to ground.
3) Charger IC ISL6259 bad. Very difficult to change. Need high end soldering skills.
4) SMC bad. Need BGA rework station.
5) R5280/R5281 pullup resistors blown.

You will need a bit of ol' fashion Sherlock sleuthing skills to figure out which one

 

[kreliz]

Clever use of conductive ink. Never used it before so I hope it is reliable over time. At least you know where to start if it were to fail again

The fact that it does not detect battery even after replacing with new one means that the SMC (System Management Controller) is not communicating with the battery. This has nothing to do with the DC-in board in case anyone reading is in the same circumstance.

There is an I2C (pronounced Eye Squared See) serial communications bus that the SMC, charger ISL6259, and Battery use to communicate with each other. These signals are easiest to access at the battery connector. They would be pins 4 and 6. When the MacBook is on you should see 3.4V on these lines. With the macbook is turned off and battery disconnected you can also measure resistance of these pins to ground to make sure they are not shorted.

If you follow the I2C around the schematic you can see how it communicates between the SMC, charger, and battery. In your case this bus is not working. Possible causes:

1) D6950 shorted to ground. If you measure a low voltage on the lines (not 3.4V) this could be the cause.
2) C6953 and/or C6952 shorted to ground.
3) Charger IC ISL6259 bad. Very difficult to change. Need high end soldering skills.
4) SMC bad. Need BGA rework station.
5) R5280/R5281 pullup resistors blown.

You will need a bit of ol' fashion Sherlock sleuthing skills to figure out which one

Thanks for the quick reply. The only thing i have managed to locate so far, i think, is D6950. I am measuring 0.38 on pin6 and 2.40 on pin4. No shortage detected. I will need some time to locate the rest. Pretty much abacadabra to me.

 

[CasaOui]

Macbook Pro i7 15" (Mid-2012) No Backlight

Hello everyone,

I do have a backlight problem, but my logic board is slightly different of the ones covered in this thread. I would appreciate all the help.

I have this problem for over 2 moths and after searching the entire web for answers (youtube, macrumors, google etc) but with no success.

The problem is that I had a wine accident with my MacBook Pro mid-2012 15" (A1286 EMC 2556). After this accident I've immediately disassembled the MacBook and cleaned the logic board with Isopropyl alcohol (96%) let it dry for two weeks while waiting for the new keyboard since I'm sure the keyboard takes the most damage in this cases. I also changed the cable (screen)

So after two weeks I've received the keyboard and re-assembled the MacBook. Everything worked perfect for almost a week and after that the screen would turn black and stay that way until I restart the machine and again the same thing happens over and over.

after a few days the MacBook powers up and play the apple sound but the screen stays black. With a flashlight I see the Apple Logo and after a while I can see the background (of my two kids) so the MacBook does power up and loads the OS, but nog backlight.

I did a lot of searching just to find out where the responsible backlight inverter is or ic or chip or schematics, but no answers on the net. I do have experience with electronics and replacing things and also have the right equipment (rework/reballing/soldering station) but no idea what I should replace.

I hope someone here can help me trough this. I've attached some pics of my logic board. Let me know if more detailed pictures needed.

Thanks

 

[kreliz]

You will need a bit of ol' fashion Sherlock sleuthing skills to figure out which one

And in doing so, i believe i found the issue. I'm getting 3.40V going to both R5281 and R5280. However i get 2.40V going from R5281 to IC and 0.38V from R5280 to IC. Corresponding with the readings from pin 4 and 6 on the battery connector.

But how do i check if D6950 is also shorted to ground?
And i should probably check C6953 and C6952 too no?
However i haven't been able to find the BIL connector (J6950) till now.

This is good fun. Learning a lot at the moment.

EDIT:

Based on this,

should i be getting these to replace R5280 and R5281?

 

[BacklightFuse]

820-2101

Hello everybody!!

I have a 820-2101A board, used to work fine, but now I have no image on lcd (INVERTER VERSION), I do have video on external when ldvs is disconnected. I've measured 12v on the backlight connector and inverter is good, tested with 2 other working lcd screens so the issue is not the inverter nor the cable or lcd screen. I do have the schematics but i dont have the board view so its getting hard to find the components. Do you guys think it has to do with the u9560?? any suggestions please??? thanks in advance!!!

 

[abuzar1]

Guys so I bought this used Macbook Pro 15" Late 2008 Unibody

It had a weird backlight issue where if you turned it up too much it would turn off but if you kept the backlight at a low level it would be fine. I plugged in a different display assembly to it and it was working fine so I assumed the logic board was fine.

I let it sit for it for a few months and finally ordered an LCD for it. I changed out the panels and now there is no backlight at all. I swapped in a working display and it worked fine. I swapped in a different logic board and both my displays are working fine. So now I'm to assume a fault with the logic board.

I've searched through this thread but I still cannot find a way to pinpoint the fuse location on my board. Could someone help me out? I have attached pictures.

EDIT: If someone could please pinpoint approximately where it will be I can take a up close picture.