MacBook Pro Unibody - No Backlight - Logic Board Question

[Astroboy907]

The fuse doesn't give any sign of life.
Should i short it?
I don't have any option to find an original fuse.
Thank you

Try Digi-Key. They area a HUGE company here in the US that I *think* ships pretty much anywhere. You just want a standard 0402 2A 32v fuse (or 10... trust me they get lost)... And if they won't ship there... If you have any friends in the UK or other general Europe that could re-route the package to you..

And DONT short it... If I had shorted mine, it wouldve totally blown... My LDVS pin was shorting out the backlight circuit.

 

[l.a.rossmann]

If they won't ship it to you PM me your address and I will ship you some of mine. It'd be the cheapest form of mail so it'd probably take forever to get there though. But don't short it, it'll just end in tragedy.

 

[FabianBasha]

Thank you.
I found an old motherboard with this type of fuse in it.i'll try to switch it.
Thank you

 

[l.a.rossmann]

Try Digi-Key. They area a HUGE company here in the US that I *think* ships pretty much anywhere. You just want a standard 0402 2A 32v fuse (or 10... trust me they get lost)... And if they won't ship there... If you have any friends in the UK or other general Europe that could re-route the package to you..

And DONT short it... If I had shorted mine, it wouldve totally blown... My LDVS pin was shorting out the backlight circuit.

Shorting the fuse would've fixed the problem by removing that silly shorting LVDS pin.

 

[Dadioh]

Heres an example of how the pad look

There is also the possibility that it is an unused pad if there are no connections. If the pad was originally connected then it only had 2 options.

1) Surface trace leading directly to the component that it was connected to.
2) Short trace to a via that then tunnels down to another internal trace or a power/ground plane.

If the example you show is the actual pad you are talking about then I do not see evidence that it has a surface track or even a nearby via that it would have connected to.

 

[javier castillo]

There is also the possibility that it is an unused pad if there are no connections. If the pad was originally connected then it only had 2 options.

1) Surface trace leading directly to the component that it was connected to.
2) Short trace to a via that then tunnels down to another internal trace or a power/ground plane.

If the example you show is the actual pad you are talking about then I do not see evidence that it has a surface track or even a nearby via that it would have connected to.

Heres an actual picture.

 

[Astroboy907]

Shorting the fuse would've fixed the problem by removing that silly shorting LVDS pin.

Lol... my wording sucks at 11pm....

 

[Dadioh]

Heres an actual picture.

Is that a 15" or a 13"?

That end of the connector is either pin 30 or pin 40. See images below. There is an unused connection point at that end of the connector.

 

[FabianBasha]

My situation just got A LOT WORSE...

Replaced the fuse like i was supposed to.
Reassembled the machine.
Tried to power it up and as soon as it played the chimes sound it just DIED!
Plugged it on ac and my magsafe stays green showing it's not charging.
Dissassembled the whole thing looking for any fried component and found nothing.
Reassembled and tried to start it via the logic board connectins.
No luck.
Seems like it's dead and gone.
Any oppinions?
Or should i start looking for a new logic board?

Thank you!

 

[l.a.rossmann]

My situation just got A LOT WORSE...

Replaced the fuse like i was supposed to.
Reassembled the machine.
Tried to power it up and as soon as it played the chimes sound it just DIED!
Plugged it on ac and my magsafe stays green showing it's not charging.
Dissassembled the whole thing looking for any fried component and found nothing.
Reassembled and tried to start it via the logic board connectins.
No luck.
Seems like it's dead and gone.
Any oppinions?
Or should i start looking for a new logic board?

Thank you!

It could be a number of things. Improper reassembly, too much heat used in the desoldering process. I tested the heat resistance on a problematic Unibody board that I had frankensteined to work with wires all over it. I would never use this for a customer, so it sits here to test LCDs, keyboards, etc. I heated it as much as I could, I couldn't mess up the board with heat as hard as I tried. They are very resilient.

There are times where I've replaced the wrong component. It gets late, it's board #9 of the day, my eyes glaze over, and I replace a diode with a fuse. **** dies and blows up, and the board's on me for whomever I was fixing it for. I'm not proud of it but it happens to everyone at one time or another. Double check your work - did you really replace the fuse in that picture?

 

[FabianBasha]

Yess i really did.
I am really sick of this.
Could you please point me where i could find the cheapest logic board replacement?
Or if someone thinks he could repair mine,i would be very happy to ship it to you.

 

[javier castillo]

Is that a 15" or a 13"?

That end of the connector is either pin 30 or pin 40. See images below. There is an unused connection point at that end of the connector.

wow dude, you're amazing. . Thanx for that schematic. I now cancelled out pin 5 and 37 thanx to you. 15 inch macbook pro.


One last question, are pin 38,39 and 40 supposed to be connected to the same component because the last pin that i'm missing is pin 38. It seems like pin 38 is directly connected to the component without no leads/copper wire. How can i reconnect the pin?

 

[Dadioh]

wow dude, you're amazing. . Thanx for that schematic. I now cancelled out pin 5 and 37 thanx to you. 15 inch macbook pro.


One last question, are pin 38,39 and 40 supposed to be connected to the same component because the last pin that i'm missing is pin 38. It seems like pin 38 is directly connected to the component without no leads/copper wire. How can i reconnect the pin?

I would solder on the new lvds connector with 39 and 40 soldered to the logic board as usual. Then bridge pins 38 39 40 together with solder. The reason the 15" have 3 pins is that they have more LEDs to drive and therefore more current. If you bridge the pins you will still share that current across the 3 pins on the lvds connector.

 

[kellygeorge]

Water damage

Hello there Dadioh and everyone else watching this thread. I stumbled across this thread searching for some info on liquid damage to a unibody MacBook (not a pro). I read a bunch of pages and found some pretty similar symptoms, but was still left with some questions. Here's the situation:
A friend just came to me with her MacBook that she had just spilled a lot of water on (laptops and jacuzzi tubs don't mix). She said the laptop shut itself off when it happened. I removed the battery, the hard drive, the ram, and the bottom casing and tried to dry the whole thing out with a blow drier. All the pin cables were damp when I started. After drying it out I replaced all the parts and pressed the battery indicator light. It worked. I plugged it in, and the MagSafe adaptor lit up like it is supposed to. When I turned it on it lit up and the apple logo appeared. Then the screen went blue, and then completely black. Pressing keys didn't seem to do anything. I tried booting holding option or holding apple+V for verbose but it booted the exact same (maybe the keyboard doesn't work). I tried booting hooked up to an external display and the exact same result: it went dark after the apple logo.

so, I don't know what the problem is. The fact that the screen lights up at all tells me it's not the backlight. Seems like the logic board is fried, but if that is the case then I'm surprised it boots at all. Any thoughts or ideas on what to try next?

Ps. Sorry it's so long. And congrats on the 2 year anniversary of this thread coming up this month

 

[javier castillo]

I would solder on the new lvds connector with 39 and 40 soldered to the logic board as usual. Then bridge pins 38 39 40 together with solder. The reason the 15" have 3 pins is that they have more LEDs to drive and therefore more current. If you bridge the pins you will still share that current across the 3 pins on the lvds connector.

Hey dadioh, i dont know how to thank you. I actually fixed this bad boy, and it was all thanx to you. You are seriouslly amazing!!!

 

[cmdrdata]

Hello there Dadioh and everyone else watching this thread. I stumbled across this thread searching for some info on liquid damage to a unibody MacBook (not a pro). I read a bunch of pages and found some pretty similar symptoms, but was still left with some questions. Here's the situation:
A friend just came to me with her MacBook that she had just spilled a lot of water on (laptops and jacuzzi tubs don't mix). She said the laptop shut itself off when it happened. I removed the battery, the hard drive, the ram, and the bottom casing and tried to dry the whole thing out with a blow drier. All the pin cables were damp when I started. After drying it out I replaced all the parts and pressed the battery indicator light. It worked. I plugged it in, and the MagSafe adaptor lit up like it is supposed to. When I turned it on it lit up and the apple logo appeared. Then the screen went blue, and then completely black. Pressing keys didn't seem to do anything. I tried booting holding option or holding apple+V for verbose but it booted the exact same (maybe the keyboard doesn't work). I tried booting hooked up to an external display and the exact same result: it went dark after the apple logo.

so, I don't know what the problem is. The fact that the screen lights up at all tells me it's not the backlight. Seems like the logic board is fried, but if that is the case then I'm surprised it boots at all. Any thoughts or ideas on what to try next?

Ps. Sorry it's so long. And congrats on the 2 year anniversary of this thread coming up this month

If it got to the Apple logo, I'd say the MOBO is probably ok. I suspect the hard drive also got water, so if that is the case this is strictly an OSX issue. Try booting from DVD and see if it comes up ok. However, I am thinking that if you did not take apart the system completely to individual part you should disconnect the battery and magsafe and let the entire unit dry up for a week or so to make sure that everything is dry just to make sure there is no water elsewhere.

 

[Dadioh]

Hey dadioh, i dont know how to thank you. I actually fixed this bad boy, and it was all thanx to you. You are seriouslly amazing!!!

You are welcome. Glad to hear you got it fixed.

----------

If it got to the Apple logo, I'd say the MOBO is probably ok. I suspect the hard drive also got water, so if that is the case this is strictly an OSX issue. Try booting from DVD and see if it comes up ok. However, I am thinking that if you did not take apart the system completely to individual part you should disconnect the battery and magsafe and let the entire unit dry up for a week or so to make sure that everything is dry just to make sure there is no water elsewhere.

Good points. Also, if you can get a ziplock bag or other plastic bag large enough to put the macbook in then I would seal the Macbook along with a bunch of those desiccant bags... the ones with the silica beads that you are not supposed to eat.... That would allow you to completely dry the unit out. Water trapped in small spaces can last a long time without some encouragement.

 

[aleds1234]

WLED position in a1286

How about, I have questions regarding chip WLED, I have damaged the lp8545, lp8543 I can replace it with a? It's the same? change something?
I can help by removing the WLED a macbook pro unibody 15 "A1286, does not bring any brand and will set the new one will have a picture of the position of the WLED on this motherboard, it was my fault in not noticing as was situado.Adjunto an image I found on this wonderful forum but did not notice the letters of the WLED. Thank you.

 

[rnccen]

I have a 2008 logic board A1286 and ordered fuse from digikey to replace. However, I am having a very tough time getting the old fuse to desolder....what temp have others used to get the fuse off the board?

Thanks

Paul

 

[Dadioh]

I have a 2008 logic board A1286 and ordered fuse from digikey to replace. However, I am having a very tough time getting the old fuse to desolder....what temp have others used to get the fuse off the board?

Thanks

Paul

I use two soldering irons. One at each end. Usually per-wet the ends of the fuse with solder to ensure good contact. My metcal tip is the 700deg variety and my other iron has a 500deg setting.

 

[cmdrdata]

I use two soldering irons. One at each end. Usually per-wet the ends of the fuse with solder to ensure good contact. My metcal tip is the 700deg variety and my other iron has a 500deg setting.

Here's a better trick: Instead of removing the old one, just stack the new one on top of the old and solder the two ends. since the old fuse is "open" it should cause no problem.

 

[Dadioh]

Here's a better trick: Instead of removing the old one, just stack the new one on top of the old and solder the two ends. since the old fuse is "open" it should cause no problem.

Even better

Trust commander data to find a more efficient solution

 

[ptsoc]

A1278 another one with water damage

hello everyone. thanks so much for this thread and all the knowledge that has been posted. I've got a 13" MBP mid 2010 A1278 board with liquid spill damage and no backlight. I replaced the LVDS. thanks to this forum, I was able to locate the fuse. it was open. I replaced it sucessfully and it blew. if someone has a schematic for an A1278 I'd appreciate it. I downloaded the one earlier in this thread and it was for the 15" MBP. I do not have the nessessary 3 volts on pin 4 of the WLED driver. I believe that since the fuse is blown I'm not going to get much voltage at the driver untill the short is resolved. I cheked all pins of the wled driver no shorts to ground, but not sure how to tell if it is shorted internally or the location of any other components that may be contributing to the problem. any tips or pointers would be appreciated. Thanks

EDIT: ok I double checked my readings on the WLED driver chip and found that pin 24 (SW) appears to be grounded. not sure if this ground is internal to the chip or external. it is an LP8545. according to the "typical" set up on the data sheet from national semiconductor it would appear there could be several capacitors that could be shorted, but as I don't have a schematic its hard to tell how this is set up. any help would be appreciated. thanks

 

[FabianBasha]

Finally some good news!

1-st i would like to thank you all for this great thread.if i hadn't read tis thread i would have ended up spending hundreds of $$$ in vain.

I finally have some good news.
As i told you i had my fuse replaced and my mbp died as soon as i tried to turn it on.
Turns out i had a different fuse and instead of frying it kept the circuit on semi-bricking my logic board.
I let the board sit for 2 days and then following the instructiones found here:
http://www.scribd.com/doc/79035001/30/Backlight-Issue-No-Backlight#outer_page_138
i started troubleshooting.the good news is that my logic board works just fine with an external display and i don't think i need to buy a new one but my problem is in the lvds connector or some other component inside the display assembly.
Here is a picture of my lvds:
http://img819.imageshack.us/i/imagefod.jpg/

As you can see the last two Pins look like crap.according to the schematics posted here those are the pins for the backlight(correct me if i am wrong).

My question is.
What do you suggest me to do?
Try disassembling the lcd and locate any fried component?
Try replacing the lvds cable hoping nothing else has gone wrong?
Or buy a new display assembly and get it over with?

Thanks again for all your help!

Ps:Hope the Apple Technician Guide i posted here helps some poor soul like it did for me.

 

[ptsoc]

A1278 schematic

Ok I was able to locate a schematic of the A1278. it should be attached to this post as a pdf. Now to determine the component layout and traces. any advice is still welcome. thanks