Sorry buddy, your picture is still blur, do you have a diode mode on your multi-meter? Pin 1 is on the bottom of your picture of the LVDS connector.
Is this suppose to be Ohms??? or Volts???? if it is Ohms then you fuse is fine!!
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MacBook Pro Unibody - No Backlight - Logic Board Question
- Thread starter Dadioh
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Sorry buddy, your picture is still blur, do you have a diode mode on your multi-meter? Pin 1 is on the bottom of your picture of the LVDS connector.
Is this suppose to be Ohms??? or Volts???? if it is Ohms then you fuse is fine!!
Thanks again picked the wrong side of the connector for pin 1 Measuring from left side of the connector in the photo pin 3 is reading .545 ohms in the diode mode and either side of the fuse I am reading .432 ohms. Not sure where to find the schematic and board view? I did see a couple of sites but not sure how to order or what i am getting
Well if you are getting .545 ohms at pin 3 and just confirm that when you put the probes on both sides of the fuse you got 0.427 ohms then you don't have a short anywhere on the backlight circuit.
Plug the CORRECT lcd in and then the magsafe and measure the VOLTAGE (put the multi-meter in DC Volt mode) at pin 3 or 4 and BOTH ends of the fuse with the black probe on ground.
Let me know what the readout voltage is and then we can try and identify where the problem is
Rick
The voltage on either side of the fuse is 8.36 VDC. At Pin 3 .002 v (or no volts)
Ok here's a copy of the schematics and boardview for this board? Page 66 of the schematics shows the backlight circuitry. You need to find R9731 and check that there is a voltage at pin 1 and 2. Use boardview to find this resistor and tell me what the voltage is?
Also check C9714 to make sure you have 5v going into the LP8550
Also check C9714 to make sure you have 5v going into the LP8550
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Ha Pal I am totally impressed I have never reached this level before many thanks.
R9731 - pin 1 and 2 have .005v and.001v (no voltage)? C 9714 is showing 5.11v
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Ok, check for a short on pin 1 and 2 of R9731 (diode mode, red probe on ground, black probe on pin 1 and 2) and report the ohms on each side. (make sure again that the power/battery are disconnected and LCD is connected).
BTW whenever I ask for a you to check for a short make sure that the power/battery are disconnected and LCD is connected. When I ask for a voltage make again that the LCD is connected and of course power you don't need the battery.
Next check the voltage at Q9706 Pin 1, 2, 3, 4, 5 and 6
Rick
BTW whenever I ask for a you to check for a short make sure that the power/battery are disconnected and LCD is connected. When I ask for a voltage make again that the LCD is connected and of course power you don't need the battery.
Next check the voltage at Q9706 Pin 1, 2, 3, 4, 5 and 6
Rick
Thanks R9731 pin 1- .397ohms, pin 2- .522 ohms
Q9706 not sure which is pin is 1 but from top left corner clockwise pin 1 - 8.12v, pin 2 - .761v pin 3 -.383v, pin 4 -.50v, pin 5 -.576v and pin 6 - 8.36v
In boardview use the "c" button and the type in Q9706. This will the display the location of that chip. Double-click near that chip will make it larger, keep doing this until it's big enough and the click on a circle and this will tell you which pin it is. Then you can tell me the right pin to voltage.
I am learning!! so now pins 1- 8.36v, 2- .576v, 3 - .500v, 4 - .383v, 5 - .761v, 6 - 8.12v
It can't be right..... If you look at the schematics pins 1,2,5,6 are all the same output so they should all be the same voltage and pin 4 is coming from the fuse, this should be 8v according to your post #1979... are you sure you have a) the correct chip and b) the LCD plugged in?
Sorry the board was reversed when taking the measurements the reading should be 1-.003v, 2-.003v, 3-8.12v, 4-8.36v, 5-.003v and 6-.003
Tall order you mean de-solder? L9701 looks like the grey sq comp with markings 150 138 kjk??? Measure both sides out of the board? What is L9701( a capacitor?) Check for a short??
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L9004 needs replacing - L9701 is an inductor.
Measure = voltage
short = red probe on ground / black probe on both pins of the board where L9701 was.
I'm away for a week or two now.... you can start watching Louis video's on Youtube and you will lean a lot about Electronics and how the Backlight circuit works, this clip is for leaning purpose only...
Measure = voltage
short = red probe on ground / black probe on both pins of the board where L9701 was.
I'm away for a week or two now.... you can start watching Louis video's on Youtube and you will lean a lot about Electronics and how the Backlight circuit works, this clip is for leaning purpose only...
Thanks again for all the help truly appreciate it. I doubt if I can replace L9004 I have no idea what it is and it is so small I would need the equipment that Louis is using to even attempt it?? Also this board had no video prior to this component smoking?? Do you still need the readings on L9701 (off the board)?
No I have not started to remove L9701. Would it be sufficient just to lift one leg to measure the voltage at the two points?? Just upgrading myself on what the symbols mean on the schematic to avoid asking stupid questions?? I now know a L??? is an inductor.. I am in Canada. Any idea what it would cost to have a board repaired by someone like Louis?? I also have a 820-3115-B that do not power on that I would love to have the schematic and board view file on?? (Not to scare you away nor beg)
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Sorry I don't have that schematic at the moment. If I was you and if you want to do this yourself is to watch and learn board level repair with Louis. The board you are working on at the moment will be a lot easier to diagnose than a non work board for a beginner. But you will need some of the equipment that Louis or any other repairer has. You have seen how small some of these component are and you will need the equipment. You may also have to change the BGA chip (Google BGA so you know what it used)
If on the other hand if you want to send it away for repair we actually repair MBA.
Who are we?? and at what cost?? I do not have the equipment ( a soldering station and multimeter only) and may not be any advantage to buy it since I am just a retired old fart who just do this as a hobby just to keep the brain functioning.(freebies). I did pick up a couple unites off the classifieds mostly to learn Apple and maybe make a buck?? I do not pretend to have the skills for diagnosing as Louis but I still have a desire to learn?? I do certainly intend to view his videos and learn!! I have already learned considerably thank you again.
Hi guys. I have a macbook pro 7.1 with a the nvidia fault ( I think).
I have wiped the drive to do a freash install as I thought I had a power setting issue and because I wanted to start fresh.
Before I did, I ran the hardware test. All good.
Would boot fine, then turn off backlight. With intermittent on flashes. Can see desktop when a light shines thru appke logo.
After wipe, I can boot 10.6.3 on usb, but wont let me install it. But mbp works. No backlight issue.
If I boot lion on usb, turns backlight of as soon as language selection sceen comes on. Also most times, it drop to sleep. The if I leave it, it sometimes will wake and flash backlight on.
Any ideas?
Thanks.
I have wiped the drive to do a freash install as I thought I had a power setting issue and because I wanted to start fresh.
Before I did, I ran the hardware test. All good.
Would boot fine, then turn off backlight. With intermittent on flashes. Can see desktop when a light shines thru appke logo.
After wipe, I can boot 10.6.3 on usb, but wont let me install it. But mbp works. No backlight issue.
If I boot lion on usb, turns backlight of as soon as language selection sceen comes on. Also most times, it drop to sleep. The if I leave it, it sometimes will wake and flash backlight on.
Any ideas?
Thanks.
I'm attempting to fix a no backlight MBP 13" (LB #820-2533) for my father, I located the backlight fuse and determined it was blown. I ordered replacement fuse from DigiKey and replaced it which was no easy task, 0402 case is a tough hand solder. I continuity tested the new fuse before power on and it had continuity, power on and still no backlight. Tested fuse again after power off and no continuity. I'm willing to undertake replacing the WLED driver but am wondering if this fuse blowing is indicative of another issue. Can anyone provide insight before I dig further?