Ok so I tested the wled driver, I found it on the side with the CPU/gpu and it did have the app-01a markings. I tested each pin and some pins and the majority of maxing near 2 on the multimeter when measuring with the x100 setting. If I remember correctly a few pins (maybe 1 or 2) seemed like they were the ground pins since the needle didn't move like it did on the others. I retested the fuse and got nothing, so I need to have that replaced for sure. I'm wondering if me getting readings on some of the pins on the WLED driver is a good sign, or if it might be possible it is still shorted out?
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MacBook Pro Unibody - No Backlight - Logic Board Question
- Thread starter Dadioh
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Ok so I tested the wled driver, I found it on the side with the CPU/gpu and it did have the app-01a markings. I tested each pin and some pins and the majority of maxing near 2 on the multimeter when measuring with the x100 setting. If I remember correctly a few pins (maybe 1 or 2) seemed like they were the ground pins since the needle didn't move like it did on the others. I retested the fuse and got nothing, so I need to have that replaced for sure. I'm wondering if me getting readings on some of the pins on the WLED driver is a good sign, or if it might be possible it is still shorted out?
I've found my problem. I seems that there was a short on the LCD cable.
The LVDS connector has three pins which are gone.
Does anybody of you know if and where I could get a new one
Hi
Sorry to write this here, i know this thread is about backlight, But i did not find any other place about the wireless lan to write this.
Macbook 2008 unibody silver, I got it for replacement of LCD, i picked up the glass sucsesfully but i damaged the Wireless cable in the lcd cover.
When i replaced the cable, i did not mentioned that i have connected the wrong side of the cable to the wireless lan card. I connected the second side to the logic card and turned on the Macbook, it worked but i got no wireless card.
I tried to fix the cable, replace it again, replace the wireless but still can not find the wireless.
I tested the cable and the wireless card by another macbook and they are working, so it is the motherboard.
By the way i have more than 5v on the caps.
May you help me Dadioh?
Thanks for all advices
Sorry to write this here, i know this thread is about backlight, But i did not find any other place about the wireless lan to write this.
Macbook 2008 unibody silver, I got it for replacement of LCD, i picked up the glass sucsesfully but i damaged the Wireless cable in the lcd cover.
When i replaced the cable, i did not mentioned that i have connected the wrong side of the cable to the wireless lan card. I connected the second side to the logic card and turned on the Macbook, it worked but i got no wireless card.
I tried to fix the cable, replace it again, replace the wireless but still can not find the wireless.
I tested the cable and the wireless card by another macbook and they are working, so it is the motherboard.
By the way i have more than 5v on the caps.
May you help me Dadioh?
Thanks for all advices
Hi Mori3000,
have you checked the WLAN antenna?
If the cable and the air port card is working fine, it should be the next possible failure.
Regards,
Here are a few things to try. The most probably cause would be pins bent or damaged inside the connector on the logic board. That connector is very delicate and easy to catch and bend pins when plugging in the cable. Try keeping the cable plugged in and checking to see if there are any shorts to adjacent pins.
Attachments
It is good if you can get accurate measurements of the resistance to ground for all pins. Finding an issue on the WLED driver is not just a matter of whether something is zero ohms or Megaohms. Sometimes the issue will show itself because something that is supposed to be 300kohms is now 3kohms. I think you need to research how to read your meter and document the readings that you are getting for each pin. Then compare to the table posted earlier in the thread. Using normal fat probes on your multimeter does make it very difficult because the pins are so fine. You might have to invest in fine tip probes to make progress.
Hi Dadioh,
I have read through this thread and it's really amazing! However, from what I can tell the problem I have is that a fuse has blown on the logic-board close to the LVDS cable due to me replacing the LCD screen as it was cracked.
The replacement went okay but the new LCD was faulty with a loose internal connection which I found by moving the inverter attached to the bottom of the LCD. While doing this the backlight just stopped working and now I have installed a working LCD but I have no backlight.
So, from reading this thread it would appear that a fuse has blown but I'm lost as to where a which one it might be, please help!
I have attached a pic of the Logic-board close to the LVDS connection for you to have a look at and possibly tell me where the fuse might be and also a pic of the laptop specs.
Thanks so much for your help!
Best Wishes.
F
I don't have personal experience with the polycarbonate unibody. I don't see the fuse on the top so it is probably on the back side of the board. If you can post a picture of the back then I may be able to find it. Or, if someone who has worked on one of these models knows where the fuse is then a picture would be very helpful.
Really thanks you,
I am sorry if i am not clear enough.
I put the wrong side of the cable in the Wireless card not in the motherboard
( i do not mean that i changed the two sides of the cable,up and down).
my foult was when i connected the cable to the wireless card i did not mentioned that i have to rotate it.
And now the cable and the wifi card are working with another motherboard but not with the old one.
Just wanted to describe the problem better.
Thanks
Yes. I understood your description. I was just thinking that in the process of your troubleshooting you must have unplugged and plugged in the cable several times. I was guessing that during one of those plug ins that it could have damaged the connector. Otherwise, the points I highlighted should be checked.
Good luck
Alright so I made my pins fine by using extensions, and yes there was a large difference in the readings. This is what I recorded using the x100 setting which should be mohms
1. 2.2
2. 1.5
3. 2.01
4. 2.6
5. 1.99
6. 1.8
7. Between 1.8 and 1.9
8. 0 (I had assumed this was a ground but according to another post of yours it shouldn't be)
9. Between 1.9 and 2
10. 1.99
11. 2
12. 2
13. 2
14. Between 2.1 and 2.2
15. Same as 14
16. 2.1
17. 1.2
18. 1.6
19. 0.4
20. 1.8
Keep in mind this is with the confirmed blown fuse, so that might be a reason the numbers are thrown off?
This is the post I found: https://forums.macrumors.com/threads/972699/
I posted some pictures here: http://www.flickr.com/photos/24815933@N07/6887540530/
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Hi new to the forum this is a very good thread i've read quite abit of it but I'm confused hope somebody can help me!
I have a Macbook 13-inch Aluminum Late 2008 it had water split over it and now backlight does not work!
I have checked every fuse i can see/find they all check out ok so my question is What one is the normal one to blow? What else should i check? What should be the correct ohms for the WLED Driver pins?
It also looks like a resistor or something is missing see pic and also a pin could be missing again see pic
The Photo is here!
I have a Macbook 13-inch Aluminum Late 2008 it had water split over it and now backlight does not work!
I have checked every fuse i can see/find they all check out ok so my question is What one is the normal one to blow? What else should i check? What should be the correct ohms for the WLED Driver pins?
It also looks like a resistor or something is missing see pic and also a pin could be missing again see pic
The Photo is here!
I have a macbook that is not turning off or going to sleep when i close the lid. I have fixed the backlight. but one of the pins on the lvds cable is broken do you think thats the pin for the magnetic switch?
I think you have a lot more going on here than those two things you've pointed out. See that chip that says TDK that's all blown.
What model MacBook? The sleep circuit is unrelated to the lvds cable. In the aluminum unibody models it is located in a flex circuit attached to the aluminum top case. On the 13" MBP it is on the right side looking from the bottom of the case and attaches next to the battery connector. On the non-pro aluminum 2008 it is on the other side and attaches next to the trackpad connector.
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That is the magnetics for the Ethernet port. It is a protective cover so the coils may still be ok.
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Looks like the 2 pins on the lvds connector that carry the 27V to the backlight. They often rot away after liquid spill. You will probably need to replace the lvds connector.
The photo is a bit fuzzy so I can't tell what the resistor is. Can you get a clearer shot?
Hi,
Sorry to write here , i really hope i can fix it .
my macbook pro 13 is 2009 mid , i power on it , i can see only white screen ,but when i connect to external monitor ,it can work everything .
so i tried replace lcd / lvds cable and lvds socket on mb , but still show white screen. hope someone help me , which part should i test to find out the problem ?
Thank you very much
Sorry to write here , i really hope i can fix it .
my macbook pro 13 is 2009 mid , i power on it , i can see only white screen ,but when i connect to external monitor ,it can work everything .
so i tried replace lcd / lvds cable and lvds socket on mb , but still show white screen. hope someone help me , which part should i test to find out the problem ?
Thank you very much
Hello
I have learned a bit more since then.I just took the part from parts board & thought it was a resistor.Checking schematic I believe it was an inductor.They look almost the same as resistors.This was on the aluminum unibody non pro so I don't know where it is on your 2009 MBP.It was L9004 & is located just out from the 1127 fet & up from where D/C jack plugs in..Hope this helps
Just checked 2009 board & its in almost same place .Good luck
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Hi, thank you very much , you mean this one ?
No its just up from what you have marked.I think there should be an inductor where you have arrow in pic,it maybe L9008 Good luck
Attachments
MacBook Pro A1278
Hi,
Sorry to post this if it has already been posted here, i have read through most of the posts and couldnt find exactly what i needed to find out.
I have a MacBook Pro 13" that had red wine spilt on to it, i have replaced the keyboard and cleaned up the mobo but the backlight of the LCD isnt working (i can just about see the lcd display).
I've tried a new screen and new cable and get the same results so guessing its a fuse or other componant on the mobo, as mentioned in a few posts here.
I have looked and found what i think is the fuse as its the only small component with a white dot in the center that i can find, i just want to check this is correct before i change it and also another componant looks to be problematic so i was hoping for some feed back on this, i have circled the componant and what i think is the fuse.
Thanks in advance for any help and i apologise if this has been covered already, but please dont shoot the noobie
Hi,
Sorry to post this if it has already been posted here, i have read through most of the posts and couldnt find exactly what i needed to find out.
I have a MacBook Pro 13" that had red wine spilt on to it, i have replaced the keyboard and cleaned up the mobo but the backlight of the LCD isnt working (i can just about see the lcd display).
I've tried a new screen and new cable and get the same results so guessing its a fuse or other componant on the mobo, as mentioned in a few posts here.
I have looked and found what i think is the fuse as its the only small component with a white dot in the center that i can find, i just want to check this is correct before i change it and also another componant looks to be problematic so i was hoping for some feed back on this, i have circled the componant and what i think is the fuse.
Thanks in advance for any help and i apologise if this has been covered already, but please dont shoot the noobie
Attachments
15 inch Mac Book Pro Mid 2009
I'v taken the board out of the shell and cleaned it up with 99% isopropyl alcohol. The backlight still doesnt work. I checked the fuse and when the multimeter is set at 200 ohms i get a reading of 00.4. Any suggestions now?
I believe I've found the right fuse however the forum will not allow me to post a picture
I'v taken the board out of the shell and cleaned it up with 99% isopropyl alcohol. The backlight still doesnt work. I checked the fuse and when the multimeter is set at 200 ohms i get a reading of 00.4. Any suggestions now?
I believe I've found the right fuse however the forum will not allow me to post a picture
thanks for your help , but finally i replace the video chip and solve the problem .