MacBook Pro Unibody - No Backlight - Logic Board Question

[a1286corei7]

Need help! no backlight on my A1278 Core i5 macbook pro

I have been following this board for a long time.
Finally has a chance to post and ask for help.

I am familiar with component repair as I've done it a lot on Playstation 2.
But I am sure Macbook Pro logic board is different, I am willing to learn though.

Please help me identify WLED and the fuse on this logic board
from A1278 EMC 2419 13 inch macbook pro

See the photos attached.

thank you so much..

 

[rogas]

After extensive search

Yup. That would be the backlight fuse. If it is blown you need to replace it. Resist the temptation to bypass it or you may end up causing further damage. If the cause of the initial fuse event is still present you will just blow another fuse. If not... well there is smoke inside all electronics....

hello Dadioh,

after an extensive search and with the graet help of this forum, i ended up finding the following parts blown.

the 2A fuse (F9800 in schematic)
the 100K resistance (R9701)
and as a it seems the APP_1A wlde driver.
Is there any chance i can find that component? It seems that this is my only problem now...

 

[Dadioh]

hello Dadioh,

after an extensive search and with the graet help of this forum, i ended up finding the following parts blown.

the 2A fuse (F9800 in schematic)
the 100K resistance (R9701)
and as a it seems the APP_1A wlde driver.
Is there any chance i can find that component? It seems that this is my only problem now...

I have not found a source for this part. It seems to be apple custom. I pull them off of my spare parts boards.

 

[Igek]

Hello,

I need some help. I need to know what type SMD is missing on my mainboard. ( the top one in the red circle is missing on my mainboard )

Ad this moment my screen is complete dead. The system it self is working fine when I use a external monitor.

It is a MBP early 2011 model ( A1278 )

thanks Thanks in advance

Hello,

Can someone help me whit a schematic for my MBP?
I still ssearching for the missing component. So pleas help

Thanks

 

[shadowscott]

macbook A1181 backlight---smoke

So I had a bad backlight inverter, and stupidly instead of buying a new cable which needed to be replaced, I tried splicing the wires together and I guess they touched metal and poof. Smoke came up (just a little) but no more video or light on the macbook screen, and it wont output to an external monitor anymore. Here's a picture of what seems to be busted (L9403 inverter I guess?)

I hope one of you could definitively say that this is the issue so maybe I can try desoldering it and buying a replacement whatever it is. I used a schematic that I found online for my computer and found this info for the L9403 (assuming that is the one that is burnt out)

L9403
FERR-120-OHM-1.5A
0402-LF

Please let me know if you have any ideas.

 

[Axess19]

Hi Axess19

Can you send me a email, maybe we can help each other. I can respond faster by mail.

Sorry for the late reply.

markpronk at gmail dot com

Hey IGEK i just sent u an email.

 

[peislander]

So I had a bad backlight inverter, and stupidly instead of buying a new cable which needed to be replaced, I tried splicing the wires together and I guess they touched metal and poof. Smoke came up (just a little) but no more video or light on the macbook screen, and it wont output to an external monitor anymore. Here's a picture of what seems to be busted (L9403 inverter I guess?)

I hope one of you could definitively say that this is the issue so maybe I can try desoldering it and buying a replacement whatever it is. I used a schematic that I found online for my computer and found this info for the L9403 (assuming that is the one that is burnt out)

L9403
FERR-120-OHM-1.5A
0402-LF

Please let me know if you have any ideas.

I had a couple boards that I had to replace that component to get display/backlight working again.I can't remember if it was just for backlight or display too.I would start with replacing it & see what happens.I believe a 0 ohm resistor would work for testing purposes if you can't find correct part but not sure.Dadioh would know more about that.
Good luck

 

[Dadioh]

So I had a bad backlight inverter, and stupidly instead of buying a new cable which needed to be replaced, I tried splicing the wires together and I guess they touched metal and poof. Smoke came up (just a little) but no more video or light on the macbook screen, and it wont output to an external monitor anymore. Here's a picture of what seems to be busted (L9403 inverter I guess?)

I hope one of you could definitively say that this is the issue so maybe I can try desoldering it and buying a replacement whatever it is. I used a schematic that I found online for my computer and found this info for the L9403 (assuming that is the one that is burnt out)

L9403
FERR-120-OHM-1.5A
0402-LF

Please let me know if you have any ideas.

Those ferrites just south of the backlight connector are for EMI control so you could just short it out for troubleshooting purposes.

However, not getting any image on the LCD or external is far more troubling. The lvds signals are over at the other side of the hinge and are carried on a separate cable. You may have damaged more than just the backlight

You can try by shorting the ferrite and go from there.

 

[liquid victim]

(where) is (it) the fuse?

Hi, you helpful People, and esp. @Dadioh,

I have a Late 2011 MB Pro 15" (2.2 GHz i7) that suffered a water spill.
After letting it dry with the case open for twoandahalf days, I've been using it for a week now and everything works fine, except - hence this thread - the internal LCD back light (I do have a picture visible with strong external light, and an external screen works alright.)
My logic board has some small stains left of what I guess is lime (calcium carbonate) from our relatively hard water.
After having read this thread, my hope is, that only the back light fuse is blown, and I found someone who says he can replace it.

Here are my three questions:

1) What are the chances that my baby is fine with only a new fuse, given that everything except the back light seems to be ok.?

2) Where is this fuse on the Late 2011 15" logic board? At least I could not find it on the easily accesible side (facing the back cover) from the descriptions so far. Can anyone confirm that this fuse still looks as described here (light brown with a light dot or 'F') in this model?

3) Edit: The answer is Yes, and I found it here at ifixit.Is there a way to take out the logic board complete with heat sinks, so I do not have to reapply thermal paste and so on (which I'm not comfortable with and my soldering guy does not want to do more than soldering).

 

[CoolDaddy]

Let me first start by saying that without this thread I would have no shot at figuring out and attempting to fix my friends macbook pro, thank you. It is the A1286 model (early 09 15" 2.53). I tested the fuse and it was an open circuit. I found someone local that can work with soldering that small of an object. When he did it, he just soldered it on top as someone suggested because he had issues taking old one off. We tested it and it was no longer an open circuit. When I put it back together and tested it, the light was still out but could see images if I shined flashlight or hooked up external monitor, as I could before the replacement.

I guess the next step is to check the WLED driver but before I take it apart again I wanted your opinion on the LVDS cable. I am going to include picture of it, the 2nd to last and 3rd to last pins (on side that handle the video) both are no longer gold and the back side has what looks like a small chunk missing.

Do you think the cable could be damaged? And can that be tested? Should I still check the WLED driver first?

Sorry for the quality, if they dont work I will try get something better.

Thanks
CD

 

[Mori3000]

Hello guys

Today i have got a very confusing Macbook pro ( at least for me ).

It is a Macbook Pro 17" 2009 A1297.

When i open program or websites which hav white backgrund i see alot of pink small lines in the screen.

At the begining i thought that it could be the LCD or the LVDS cable, but after the replaceing both part i still had the same problem, then i tried to head the graghic chip and the component close to LCD connector but i still have the same issue.

By the way, i heated the components close to the LCD connector, because when i runing the computer after som second this happens. If i push on the left-up side of the computer close to the keyboard so it would fix every thing and i see a white and clean page but when i leave it after some secondes it comes back.

Please some help, i attach a two photo so you can see how it is.

thanks

 

[BusterW]

It is possible that Apple have gone to a larger 0602 package and that may not have a dot. Post a high res picture of the front and back of your board near the lvds connector and I will see if I can figure it out.

Dear Dadioh sir,

I have the backlight out issue on a Macbook Air A1369. While doing the lcd replacement I did not disconnect the battery from the Logic board before disconnecting the LVDS cable and backlight cable, which more than likely blew the lcd backlight fuse.

I have read alot through this thread and assuming it is probably the f9800 fuse that is blown.

I have removed my logic board and searched on it quite extensive without finding the 0402 capacitor and or "the tiny one with the white dot"

I have found one that has a "P' on it and is somewhat near the LVDS cable port and near a 6 pin chip that is possibly the "WLED driver"(?).

Please take a look at the pics i have posted, any feedback or insight would be greatly appreciated.

I also wanna thank you as well for starting this thread, I would be SOL if i didn't find and use your knowledge and guidance to get thus far.

here are some thumbnail pics of the back

 

[Felixius]

A1286 oh ooh......

Hi everyone,

First of all my credits for everyone who has been supporting this fine thread!

Now the problem. After replacing my lcd while I forgot to disconnect my battery, my backlight stopped working while my lcd still worked. Found this thread, located the fuse, measured it and indeed fuse blown. Ordered some spare fuses, due to my soldering skills brought it to the only tech center who said they could probably do it and then the next problem arose.

The guy from the tech center desoldered the wrong part! See the attached picture red arrow part. I got the picture from this thread while my logic board is still at the tech center. The part on my logic board which is gone missing was white. Does somebody know what part this should be? Or does someone have a specific A1286 2.8 diagram so i can check it? I do got a spare logic board from a late 2008 MBP model so i can probably get the part from that one.

But now there is a second problem. The tech center now claims it is to hard for them to solder 0402 packages so i'm kinda lost. I do got all the specific tools for soldering print boards so i can practice first on the 2008 board but i was hoping someone from the Netherlands know how tot do this or a company where they can perform these repairs.

Thanks in advance for the replies!

Greetz

 

[Mori3000]

Hi everyone,

First of all my credits for everyone who has been supporting this fine thread!

Now the problem. After replacing my lcd while I forgot to disconnect my battery, my backlight stopped working while my lcd still worked. Found this thread, located the fuse, measured it and indeed fuse blown. Ordered some spare fuses, due to my soldering skills brought it to the only tech center who said they could probably do it and then the next problem arose.

The guy from the tech center desoldered the wrong part! See the attached picture red arrow part. I got the picture from this thread while my logic board is still at the tech center. The part on my logic board which is gone missing was white. Does somebody know what part this should be? Or does someone have a specific A1286 2.8 diagram so i can check it? I do got a spare logic board from a late 2008 MBP model so i can probably get the part from that one.

But now there is a second problem. The tech center now claims it is to hard for them to solder 0402 packages so i'm kinda lost. I do got all the specific tools for soldering print boards so i can practice first on the 2008 board but i was hoping someone from the Netherlands know how tot do this or a company where they can perform these repairs.

Thanks in advance for the replies!

Greetz

Hello Felixius

According to the colour of this one i think it is a capacitator and you can find it on all of the boards normally, try to find one part with same colour and the same size.

 

[Mori3000]

Hello every body

Now i have got a macbook air a1369 2011 which is liqid damage, icleaned it in nice way and now the computer works but the back light is not working.

The fuse seems working and i have 8 v on it and i have about 8.3v on the second part there.

I compered it with a working one and i should have 23 or 24v.

Does any body know where the back light driver is on this logic board.

Thanks

 

[Mori3000]

Macbook air A1369 2011

Now i have got a macbook air a1369 2011 which is liqid damage, icleaned it in nice way and now the computer works but the back light is not working.

The fuse seems working and i have 8 v on it and i have about 8.3v on the second part there.

I compered it with a working one and i should have 23 or 24v.

Does any body know where the back light driver is on this logic board.

Thanks

 

[kennethf]

Macbook Pro 13 2010 A1278 EMC:2351

Hello
Great forum
Iam working on a water damaged macbook pro 13 2010 A1278 EMC:2351.
The mac charges the battery and G3hot is good. But it wont start Great if someone could help me out where to look.

Ps I think there something wrong with my 5V supply, where can I find this on the PCB ?

Thanks

 

[Felixius]

Hello Felixius

According to the colour of this one i think it is a capacitator and you can find it on all of the boards normally, try to find one part with same colour and the same size.

Thanks Mori, on this pic it is a brown one, but if i remember it right, mine was white. Would this be a capacitor too?

EDIT: I managed to find a diagram of my motherboard. I'm not a good diagram reader, can someone read the diagram and tell me if they see the component by chance?

Cheerz

ps. i got the all the circuit diagrams for the motherboard of the MBP A1286 B- 820-2523 model(the mid 2009 2,8GHZ) if somebody needs it, pm me

 

[Felixius]

Now i have got a macbook air a1369 2011 which is liqid damage, icleaned it in nice way and now the computer works but the back light is not working.

The fuse seems working and i have 8 v on it and i have about 8.3v on the second part there.

I compered it with a working one and i should have 23 or 24v.

Does any body know where the back light driver is on this logic board.

Thanks

I guess thats the fuse indeed (the one with the P) i base my thoughts on all the previous info which is given in this topic. The fuse is brown with a white dot or a P. Check what happens if you measure it. If it give 0, its a blown fuse.

 

[cmdrdata]

I guess thats the fuse indeed (the one with the P) i base my thoughts on all the previous info which is given in this topic. The fuse is brown with a white dot or a P. Check what happens if you measure it. If it give 0, its a blown fuse.

A blown fuse should read "open" (infinite resistance when blown) when measured for resistivity. A resistance reading of zero ohms means the fuse is OK.

when measuring for voltage (with power applied) both ends of the fuse should read the same voltage if the fuse is intact/OK.

 

[ariethekid]

2 Questions

I have a Macbook 2008 Unibody. It has two problems. One is the Backlight doesn't work but the display is working.

Second, the battery charges really show. I tried two different chargers and same thing. I also changed to two different DC IN Boards. Same thing.

For the backlight, what are things I can check to make sure it works?
I checked the fuse, and it is open, but I want to know what else I need to check, because that fuse blew for a reason, so changing it may just blow it again.

Also what type of fuse is in the Macbook 2008 Unibodys?
Is it a 0402 2A fuse like most of the other macbook pros?

And I know this is unrelated to the forum but do you know if there is a forum on this site that talks about fixing the charging circuit or at the very least does anyone have a circuit diagram for the 2008 Unibody Macbook?

EDIT:
I found the circuit diagram if anyone needs it. PM me.

 

[Dadioh]

I have a Macbook 2008 Unibody. It has two problems. One is the Backlight doesn't work but the display is working.

Second, the battery charges really show. I tried two different chargers and same thing. I also changed to two different DC IN Boards. Same thing.

For the backlight, what are things I can check to make sure it works?
I checked the fuse, and it is open, but I want to know what else I need to check, because that fuse blew for a reason, so changing it may just blow it again.

Also what type of fuse is in the Macbook 2008 Unibodys?
Is it a 0402 2A fuse like most of the other macbook pros?

And I know this is unrelated to the forum but do you know if there is a forum on this site that talks about fixing the charging circuit or at the very least does anyone have a circuit diagram for the 2008 Unibody Macbook?

EDIT:
I found the circuit diagram if anyone needs it. PM me.

If the original reason that the backlight failed was due to a liquid spill then cleaning up the circuit board is usually adequate to clear the initial problem. As a quick test, with power off, battery removed, check the resistance of the backlight voltage to ground. If it is very low resistance then a fault still exists and fuse will blow again. Make sure you order more than 1 fuse so you have a backup if it blows. It is a standard 2A 0402 fast blow package.

You could also measure the WLED resistance from each pin to ground and compare to known good device. There is a table of expected values I posted earlier in the thread.

The charging circuit is problematic. I assume you have no amber LED on the magsafe to indicate charging? Does it glow solid green?

I have had quite a few with the ISL6258 charging IC gone bad. You may need to troubleshoot around that device. It may be my other thread that you are talking about. I think I have some info on there to help with power issues.

 

[ariethekid]

Board backlight and power

If the original reason that the backlight failed was due to a liquid spill then cleaning up the circuit board is usually adequate to clear the initial problem. As a quick test, with power off, battery removed, check the resistance of the backlight voltage to ground. If it is very low resistance then a fault still exists and fuse will blow again. Make sure you order more than 1 fuse so you have a backup if it blows. It is a standard 2A 0402 fast blow package.

You could also measure the WLED resistance from each pin to ground and compare to known good device. There is a table of expected values I posted earlier in the thread.

The charging circuit is problematic. I assume you have no amber LED on the magsafe to indicate charging? Does it glow solid green?

I have had quite a few with the ISL6258 charging IC gone bad. You may need to troubleshoot around that device. It may be my other thread that you are talking about. I think I have some info on there to help with power issues.

I believe liquid damage is the culprit. There is oxidation on the backlight pins of the LVDS cable and on the connector attached to the logic board. I'm thinking its probably not a bad idea to change the lvds cable and the connector on the logic board so I will probably do that.

I'm going to get some fuses from mouser,digikey, whatever is cheaper.

Also where on the Mobo is the ISL6258? I found an ISL9504 right above the ram slots on the backside (opposite the side with the CPU/GPU) of the board.

As for the charging light, when I first got it, The charge light was dim green. It would occasionally blink orange, again also dim.

And then I was fiddling with the computer and it just randomly started lighting up full again. Now it says its charging the battery when I turn it on whereas before it didn't (when the light was dim). I also noticed the battery is charging ~410 mAh. That seems really low. This seems accurate as far as why the battery charges so slow. Also I should note that when the battery is not in the computer the LED is always dim on the power cord.

EDIT: Actually if you let it sit long enough, the LED on the cord will change from dim to bright after about 5-10 minutes. Just tried it now.

I also felt a little brave and decided to short the fuse really quick and the backlight flickered on! but...I think the LVDS connector is shorted internally on the board. I'm going to take it off and replace it with a fresh one. I have a strong feeling that will fix the backlight, along with a new LVDS cable and a new fuse of course.

 

[ariethekid]

Checked the WLED today. it is an APP001. so hard to replace...but I checked all the points on the chip and it seemed all the resistances checked out except for the MOhm values. Probably because of a cheap multimeter I suspect. They can't all be out on the MOhm values.

Ordered a new fuse and a new LVDS Connector for the board, crossing fingers and hoping that fixes the problem I've been having with the display.

Time to do some work on the slow charging now.
IF any one has a boardview file for the A1278 Unibody macbook M97 they don't mind sharing, I would definitely appreciate it!

 

[numnutz2005]

2011 a1297 mbp


IMG_1573 by numnutz2007


IMG_1571 by numnutz2007


IMG_1572 by numnutz2007


sorry for the delay in posting these pics....got stuck with the fam for the holiday activities and then caught up in work and when i got a chance i found that my gf required that i "borrow" my camera that she decided to start using without my knowledge at a later time haha so yaaaa i hope the pics r good enough for figuring out where the location is on 17in early 2011 boards.