MacBook Pro Unibody - No Backlight - Logic Board Question

[emin94h]

Does anyone know if these will work as my voltage divider R9731 & R9715?

301K:
http://www.ebay.com/itm/50-X-MULTIC...al_Components_Supplies_ET&hash=item3f265fc7b5

http://www.ebay.com/itm/100-X-MULTI...al_Components_Supplies_ET&hash=item5b06007bb9

http://www.ebay.com/itm/50-X-VISHAY...al_Components_Supplies_ET&hash=item5b01cd4832

100K:
http://www.ebay.com/itm/50-X-MULTIC...al_Components_Supplies_ET&hash=item5af271329f

http://www.ebay.com/itm/100-X-MULTI...al_Components_Supplies_ET&hash=item51b59cec19

The only information I got is from the schematics which says right under the R9731/R9715:
1%
1/16W
MF-LF
402

 

[l.a.rossmann]

Does anyone know if these will work as my voltage divider R9731 & R9715?

301K:
http://www.ebay.com/itm/50-X-MULTIC...al_Components_Supplies_ET&hash=item3f265fc7b5

http://www.ebay.com/itm/100-X-MULTI...al_Components_Supplies_ET&hash=item5b06007bb9

http://www.ebay.com/itm/50-X-VISHAY...al_Components_Supplies_ET&hash=item5b01cd4832

100K:
http://www.ebay.com/itm/50-X-MULTIC...al_Components_Supplies_ET&hash=item5af271329f

http://www.ebay.com/itm/100-X-MULTI...al_Components_Supplies_ET&hash=item51b59cec19

The only information I got is from the schematics which says right under the R9731/R9715:
1%
1/16W
MF-LF
402

1% is the tolerance, meaning it cannot be more than 1% off. Higher tolerances cost more money. If something is 5% tolerance and you buy 1% tolerance, it's fine. You'll pay more, it'll be better, but no point. Just don't buy a 10% or 20% tolerance when the spec sheet says 1% or 5%

1/16/W means it can pass 1/16 of a watt before it blows up. You can buy higher power handling, but no point. Just don't buy lower!

402 is the size. This is the most important. These boards are primarily comprised of 0603, 0402, and 0201 components. Wrong size is a pain in the ass to fit or you have to try to fit it diagnolly.

Use mouser and digikey, much better than ebay for this stuff.

 

[emin94h]

1% is the tolerance, meaning it cannot be more than 1% off. Higher tolerances cost more money. If something is 5% tolerance and you buy 1% tolerance, it's fine. You'll pay more, it'll be better, but no point. Just don't buy a 10% or 20% tolerance when the spec sheet says 1% or 5%

1/16/W means it can pass 1/16 of a watt before it blows up. You can buy higher power handling, but no point. Just don't buy lower!

402 is the size. This is the most important. These boards are primarily comprised of 0603, 0402, and 0201 components. Wrong size is a pain in the ass to fit or you have to try to fit it diagnolly.

Use mouser and digikey, much better than ebay for this stuff.

You still didn't answer my question, I do not want to order from Digikey or Mouser since the shipping cost is a joke.
Ebay works just as fine, I ordered my 0603 fuses from there and they worked like a charm. The only thing I'm not sure of is if the resistor should be of Thick film or Cheramic material, the size, voltage and tolerance I already know.

 

[l.a.rossmann]

You still didn't answer my question, I do not want to order from Digikey or Mouser since the shipping cost is a joke.
Ebay works just as fine, I ordered my 0603 fuses from there and they worked like a charm. The only thing I'm not sure of is if the resistor should be of Thick film or Cheramic material, the size, voltage and tolerance I already know.

It doesn't really matter, ceramic should be cheaper so I'd buy that.

 

[emin94h]

It doesn't really matter, ceramic should be cheaper so I'd buy that.

That was all I needed to hear, thanks a lot Louis!

Just hope these resistors will work...

 

[l.a.rossmann]

That was all I needed to hear, thanks a lot Louis!

Just hope these resistors will work...

I didn't read the thread so I'm probably going to be asking you to repeat yourself.

BKL_EN is made by a voltage divider that takes the 12v and turns it into 3v. Replacing these resistors only helps if you have 12v at one side, but not 3v at the other. If you do not have 12v at the start of the voltage divider, this is a waste as you have another issue. If you do already have BKL_EN at 3v, this is a waste since you have 3v already.

Also what board is this? 820 number

 

[emin94h]

I didn't read the thread so I'm probably going to be asking you to repeat yourself.

BKL_EN is made by a voltage divider that takes the 12v and turns it into 3v. Replacing these resistors only helps if you have 12v at one side, but not 3v at the other. If you do not have 12v at the start of the voltage divider, this is a waste as you have another issue. If you do already have BKL_EN at 3v, this is a waste since you have 3v already.

Also what board is this? 820 number

They don't read anything near that, like 0,29volts where it should be 12,6 and 0,07volts where the 3 volts should be. They measure wrong resistance, the R9715 stops at 26,0Kohms & R9731 32,0 and counting Kohms which means they are fu*ked just like you said in your video. Everything else seems to be fine, at least telling from the measurements.
Board is 820-2915B.

 

[l.a.rossmann]

They don't read anything near that, like 0,29volts where it should be 12,6 and 0,07volts where the 3 volts should be. They measure wrong resistance, the R9715 stops at 26,0Kohms & R9731 32,0 and counting Kohms which means they are fu*ked just like you said in your video. Everything else seems to be fine, at least telling from the measurements.
Board is 820-2915B.

The voltage divider turns the 12v into 3v. if you don't have 12v at the top, replacing the voltage divider won't help. Do you have 12v on pin 1 of R9731? if not, you're screwed here.

See if you have 12v on pins 1, 2, 5, and 6 of Q9706. If you have 12v on Q9706 on 1/2/5/6 but don't have it on pin 1 of R9731, then that means the trace or solder pad on the board is ****ed, so you'll have to run a wire to fix that problem.

That's my guess since you said 12.6v is what you get at backlight output

 

[emin94h]

The voltage divider turns the 12v into 3v. if you don't have 12v at the top, replacing the voltage divider won't help. Do you have 12v on pin 1 of R9731? if not, you're screwed here.

See if you have 12v on pins 1, 2, 5, and 6 of Q9706. If you have 12v on Q9706 on 1/2/5/6 but don't have it on pin 1 of R9731, then that means the trace or solder pad on the board is ****ed, so you'll have to run a wire to fix that problem.

That's my guess since you said 12.6v is what you get at backlight output

I mentioned this in my earlier post, YES I do get 12,6volts on pin 1,2,3,5,6 & even pin 4 which is the input. It's the little component with 638Z4 written on it and pin 6 is the pin that transfers PPBUS_SW_LCDBKLT to pin 1 of R9731, right? So the output of Q9706 is carrying 12,6 volts but the R9731 isn't getting the voltage, what should I do?

 

[l.a.rossmann]

I mentioned this in my earlier post, YES I do get 12,6volts on pin 1,2,3,5,6 & even pin 4 which is the input. It's the little component with 638Z4 written on it and pin 6 is the pin that transfers PPBUS_SW_LCDBKLT to pin 1 of R9731, right? So the output of Q9706 is carrying 12,6 volts but the R9731 isn't getting the voltage, what should I do?

First replace the two resistors.

Then. you solder a wire to the output of Q9706 - any of the output pins will do. You solder the other end of the wire to pin 1 of R9731, at the "top" of the voltage divider. That board trace or solder bad is ****ed, so you run a wire where the trace would have been.

Then you have backlight. If you don't have backlight, we go back to square 1 and continue troubleshooting.

 

[emin94h]

First replace the two resistors.

Then. you solder a wire to the output of Q9706 - any of the output pins will do. You solder the other end of the wire to pin 1 of R9731, at the "top" of the voltage divider. That board trace or solder bad is ****ed, so you run a wire where the trace would have been.

Then you have backlight. If you don't have backlight, we go back to square 1 and continue troubleshooting.

What type of wire should I use since I don't have any LVDS cable at home to use. Think that I could use those tiny wires inside a ethernet cable RJ45 or what they're called or does it have to be molybdenum wire like you are using in your videos?

 

[l.a.rossmann]

What type of wire should I use since I don't have any LVDS cable at home to use. Think that I could use those tiny wires inside a ethernet cable RJ45 or what they're called or does it have to be molybdenum wire like you are using in your videos?

The wire inside inside CAT5 is way too thick, you'll rip crap off the board. Get creative. This wire is going from one side of the board to another so something insulated is best unless you can heatshrink it, but good luck fitting bare wire that thin through heatshrink. You could conformal coat a bare wire, but that is going to cost you more than just buying an LVDS cable and stealing crap from it.

IDE cables are decent for this but again, too thick, and it is one solid core strand, so realy easy to break. Frustrating.

 

[emin94h]

The wire inside inside CAT5 is way too thick, you'll rip crap off the board. Get creative. This wire is going from one side of the board to another so something insulated is best unless you can heatshrink it, but good luck fitting bare wire that thin through heatshrink. You could conformal coat a bare wire, but that is going to cost you more than just buying an LVDS cable and stealing crap from it.

IDE cables are decent for this but again, too thick, and it is one solid core strand, so realy easy to break. Frustrating.

One more thing, the voltage divider isnt carrying 0 volts but is very close to 0v like I mentioned earlier, something like 0,29 volts and decreasing. How does this come? Will it in any way affect the wireing or damage the WLED chip, just curious?

 

[l.a.rossmann]

One more thing, the voltage divider isnt carrying 0 volts but is very close to 0v like I mentioned earlier, something like 0,29 volts and decreasing. How does this come? Will it in any way affect the wireing or damage the WLED chip, just curious?

I don't understand the question.

 

[emin94h]

I don't understand the question.

What I meant was that the R9731 is measuring 0,29volts once the charger is connected, but I'm gessing that is as good as zero voltage...

I also saw that you wrote "First replace the two resistors" in your post where you explained how to wire Q9706 with R9731 pin1, will it make any difference if I replace them or not? I think R9731 and R9715 are dead since resistance is measuring something totally else from what they should. I will do like you told me to.

 

[gratabb]

Can anyone tell me what the approximate voltage of pin 24 (labeled sw) on the WLED driver should be for mid 2009 macbook pro?
I am getting 12v but should it be more like 40-50v ? All other pins seem to have correct voltages.
Between the inductor L9701 and the diode D9701 on PPBUS_S0_LCDBKLT_PWR_SW I have 12v.
After diode D9701 all the way to pin 40 i get 38v which is also on the feedback to WLED driver, but i presume thats not quite enough voltage because backlight still not working so thinking the WLED should output higher than 12v on pin 24 to boost it up towards 50v ?

Thanks !

 

[emin94h]

First replace the two resistors.

Then. you solder a wire to the output of Q9706 - any of the output pins will do. You solder the other end of the wire to pin 1 of R9731, at the "top" of the voltage divider. That board trace or solder bad is ****ed, so you run a wire where the trace would have been.

Then you have backlight. If you don't have backlight, we go back to square 1 and continue troubleshooting.

Louis I give up! I got my resistors yesterday (100K, 301K & 16,2K) and bought one of those heat guns to get the soldering done properly. No success what so ever, it was a real pain in the ass to solder the tiny 0402 resistors on to the small pads and after 2-3h of effort the three resistors were in place. I started with the first from above which was the the 16,2Kohm resistor and measured the resistance across the pins, got exactly 16,2Kohm on my multimeter, great now lets get over to the actual voltage divider. For some reason the R9731 measured only 33,0Kohms and the R9715 above it measured like 25,8Kohm and slowly counting which isn't even near of what it actually should measure.

I now hooked up the logic board to the charger to measure some voltage before I actually start the computer, for some weird reason the fuse now reads 15,58v on both pins and worst of all, the entire backlight circuit now showed 0v except for the Q9707 which measured 4,17v on one of the pins. Other components besides the backlight circuit also measured 15,58volts?!
That's an increase of like 3 volts, how that suddenly happened I do not know so I thought why not try replace the fuse again since I had like five 0603 fuses left and they are much quicker & easier to replace than the 0402. Guess what happened, the solder pad from the right pin came OFF the board, that was the moment I knew I'm totally ****ed and this cannot longer be fixed by me.

So I was wondering if I maybe could send you me logic board for a repair since you are way more experienced than me and have your own repair store. I really don't feel like trying to solve this myself anymore, it has already cost me 3 whole months and apr. 100 bucks. If you want more details regarding the logic board, measurements or whatever feel free to answer me. Thanks

 

[l.a.rossmann]

Louis I give up! I got my resistors yesterday (100K, 301K & 16,2K) and bought one of those heat guns to get the soldering done properly. No success what so ever, it was a real pain in the ass to solder the tiny 0402 resistors on to the small pads and after 2-3h of effort the three resistors were in place. I started with the first from above which was the the 16,2Kohm resistor and measured the resistance across the pins, got exactly 16,2Kohm on my multimeter, great now lets get over to the actual voltage divider. For some reason the R9731 measured only 33,0Kohms and the R9715 above it measured like 25,8Kohm and slowly counting which isn't even near of what it actually should measure.

I now hooked up the logic board to the charger to measure some voltage before I actually start the computer, for some weird reason the fuse now reads 15,58v on both pins and worst of all, the entire backlight circuit now showed 0v except for the Q9707 which measured 4,17v on one of the pins. Other components besides the backlight circuit also measured 15,58volts?!
That's an increase of like 3 volts, how that suddenly happened I do not know so I thought why not try replace the fuse again since I had like five 0603 fuses left and they are much quicker & easier to replace than the 0402. Guess what happened, the solder pad from the right pin came OFF the board, that was the moment I knew I'm totally ****ed and this cannot longer be fixed by me.

So I was wondering if I maybe could send you me logic board for a repair since you are way more experienced than me and have your own repair store. I really don't feel like trying to solve this myself anymore, it has already cost me 3 whole months and apr. 100 bucks. If you want more details regarding the logic board, measurements or whatever feel free to answer me. Thanks

Sure. Just know you may be better off locally. You avoid shipping, and we're not cheap. My store is located in one of the most expensive cities in the world, where everything is a ripoff, so that gets factored into the pricing for everything here. This is why I suggest you look locally first, as you may wind up spending less money locally to get the exact same service.

Price is around $205 or something with free shipping in the continental US if you use the bklen coupon from the youtube videos.

I can't promise fast turnaround on something that's been previously messed with, but what I can tell you with confidence is if I can't fix it - no one can. I've repaired boards with holes in them, boards that went on fire.. a few ripped solder pads is just another board in the pile here.

 

[thortuletz]

board number 820-2914-B, wled driver is lp8545 u9701. pin 2 is PWM for led. follow pin 2 and check resisters. Correct me if I'm wrong...

Hi again sorry for the late late response !!!
Ok so i measured the points in the picture it give me 1.455 at 2k is ok? Where do i look next? Thank you

 

[ERRDivideByZero]

Quick bit of help needed

First and foremost, Thank you EVERYONE... this thread has greatly assisted me in not only the purchase, but the troubleshooting of a mid2009 MacBook Pro.

Typical issue found here, no backlight, checked the fuse after the purchase, and it was indeed blown. After disassembling the machine, it appears to have been damaged by liquid (cola by the looks/smell/stickiness). So I cleaned up the board with some IPA and a really soft toothbrush and let it dry to see what I could do.

So what I have decided so far is the following:
I could either order and replace the fuse and hope for the best, and then probably find out that I would need another component.
OR
I bypass the fuse temporarily, see if it works, if it does, great, take out the bypass, order the fuse, replace and be done with it. If not, see what blows up, and start troubleshooting.

I opted for the latter... I'm comfortable with SMD work, and I have recently acquired a hot-air rework station, and I've been itching for a good excuse to break it in .

SO, what I need some help with is determining where to go from what I have blown up... and if someone has a schematic, that would be even more helpful. Right now I am using the schematic and boardview file for 820-2330 logic board, and although it appears close... it doesn't look exact.

Here's what I have:
Logic Board part number: 820-2523
WLED Driver part: L8543SQ (labeled on the chip, and I have found the replacement to order on digikey's site)
Blown MOSFET labeled: 638ZJ

Warning: These pictures are pretty big, I took them at full resolution on my DSLR (with macro lens and ext tubes).

First Picture - This is what I started with, and yes it appears that this has been messed with once before (to my honest surprise)
https://dl.dropboxusercontent.com/u/25239089/_MG_0006.JPG

Second Picture - This is what happened after I bypassed the fuse... magic smoke time... this was from what I can tell the boost MOSFET... but because I'm not working with the right diagram, I don't know for sure, and I will need to know what the part is so I can order it from DIGIKEY... right now I have it pegged as a FDC5612CT-ND.
https://dl.dropboxusercontent.com/u/25239089/_MG_0010.JPG

Third Picture - This is the same as the last one, but zoomed out a bit to give a little bit more board for people to see if they need to
https://dl.dropboxusercontent.com/u/25239089/_MG_0013.JPG

Thanks in advance! and let me know if anyone can assist a bit

 

[gratabb]

Can anyone tell me what the approximate voltage of pin 24 (labeled sw) on the WLED driver should be for mid 2009 macbook pro?
I am getting 12v but should it be more like 40-50v ? All other pins seem to have correct voltages.
Between the inductor L9701 and the diode D9701 on PPBUS_S0_LCDBKLT_PWR_SW I have 12v.
After diode D9701 all the way to pin 40 i get 38v which is also on the feedback to WLED driver, but i presume thats not quite enough voltage because backlight still not working so thinking the WLED should output higher than 12v on pin 24 to boost it up towards 50v ?

Thanks !

So after lots of testing i seem to have the correct voltages everywhere except for pins 31 - 36 on the j9000 LVDS connector which all have 0 volts.

Does anyone know if this means the WLED DRIVER is blown or is it because of something else ?

 

[Xenius7]

the black screen of death in my macbookpro

Hello everyone,
I have a Apple MacBook Pro 2.0GHz Intel Core i7 (15-inch DDR3) Early-2011 System.
Due to the famous misconception of this model, the ATI GPU Chip overheat thing (check this petition if you have heard of it ) . I had to reflow the logic board every three months for my board to display graphics correctly. I did it with an heatgun 5 times without any problems. But the last time I did it, I may have overheat the board with the heatgun. Now the computer start, the fan turns but I got the black screen of death (no backlight).

So I wonder if the fuse repair (or a capacitor repair) would fix it ?
I have scanned my mother board, and I found a component with a "P" on it (i circle the area in red on the pic).

I don't have a multimeter yet, is there a way to test if the fuze have failed ?
Does anybody know how to check if it's the WLED driver ?
Where can I buy an replacement "fuze" / driver ?
And which parameter to choose for the multimeter ?

Thanks for the help,
Kiss from France

 

[ERRDivideByZero]

UPDATE: MacBook Pro Unibody - No Backlight - Logic Board Question

So, I have an update:

I have acquired the schematic for my board, and it was indeed a bit different, but not too bad overall. During some troubleshooting on what could have blown the fuse in the first place (other than the obvious liquid spill), it turns out I started having issues charging the machine. So I decided to purchase a DC board. This fixed the charging issue, and I was also hoping that it would be the root cause after the liquid spill.

So far, I have replaced the DC Board, I also ordered the parts from Digikey, and replaced the Backlight driver (QFN Chip), the MOSFET that I blew up on the bypass try, and the fuse (I ordered a few of each part).

When I powered the board up, the fuse blew again. After I did a full inspection before plugging anything in again, it appears that there's obviously a problem still, and I could really use some things to check, and/or ideas for troubleshooting to figure out what parts I need to replace next.

All the parts I replaced appear to be working correctly still, so its whatever is on the other side of the fuse that I'm having the problem with... at least I think.

Thanks again

 

[ERRDivideByZero]

Quick thing to add:

So, I have an update:

I have acquired the schematic for my board, and it was indeed a bit different, but not too bad overall. During some troubleshooting on what could have blown the fuse in the first place (other than the obvious liquid spill), it turns out I started having issues charging the machine. So I decided to purchase a DC board. This fixed the charging issue, and I was also hoping that it would be the root cause after the liquid spill.

So far, I have replaced the DC Board, I also ordered the parts from Digikey, and replaced the Backlight driver (QFN Chip), the MOSFET that I blew up on the bypass try, and the fuse (I ordered a few of each part).

When I powered the board up, the fuse blew again. After I did a full inspection before plugging anything in again, it appears that there's obviously a problem still, and I could really use some things to check, and/or ideas for troubleshooting to figure out what parts I need to replace next.

All the parts I replaced appear to be working correctly still, so its whatever is on the other side of the fuse that I'm having the problem with... at least I think.

Thanks again

Forgot to note:
I have inspected the LVDS connector, as it appeared questionable when I first opened the machine. After all of the previous attempts to get the backlight working, I went back to this connecter to do some tests.

On the connecter on the board, starting at the "top" (away from the Ethernet jack):
Pin 1,2 and 3 short to each other, but not to any other pin or ground.

On the cable connection, starting on the same mating side:
Pin 1,2 and 3 short to each other, AND GROUND.

I am assuming that this is an issue, and potentially the issue causing the fuse to blow now. However I don't know the pinout of this particular connector. Please let me know if I am on to something here, and where to go next!

Thanks!

 

[gratabb]

Forgot to note:
I have inspected the LVDS connector, as it appeared questionable when I first opened the machine. After all of the previous attempts to get the backlight working, I went back to this connecter to do some tests.

On the connecter on the board, starting at the "top" (away from the Ethernet jack):
Pin 1,2 and 3 short to each other, but not to any other pin or ground.

On the cable connection, starting on the same mating side:
Pin 1,2 and 3 short to each other, AND GROUND.

I am assuming that this is an issue, and potentially the issue causing the fuse to blow now. However I don't know the pinout of this particular connector. Please let me know if I am on to something here, and where to go next!

Thanks!

I am no expert and i have only scanned your posts but usually there is 3 pins at that end that should have continuity between them. With the LVDS cable disconnected if you have continuity between any of the three pins and any of the ground pins then the cable has a short and needs replacing as far as i can tell.