Why is my MacBook screen dim?

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MacBook Core 2 Duo

모델 A1181: 1.83, 2, 2.1, 2.13, 2.16, 2.2, 또는 2.4 GHz Core 2 Duo 프로세서

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randy3833 @randy3833

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게시됨: 2017년 6월 30일

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Why is my MacBook screen dim?

MacBook A1181 Early 2008 Penryn 2.4GHz

This question has been answered successfully (screen still dim after new inverter cable AND inverter board) by suggesting to install a new top case. I have installed a new top case but still have a similar, but not exactly the same, dim screen issue.

I purchased a broken Early 2008 MacBook, seemingly needing a new Display Inverter Cable and possibly a new LCD and/or Inverter as the display was very dim. Along the way, I discovered that It needed some other repairs. After reassembly and on startup the screen was still very dim and possibly even more so. I can barely see the screen during daylight hours.

Here are the components that I replaced and troubleshooting that I've done so far:

Installed a brand new LCD display, brand new Inverter, brand new Inverter Cable, 2 new RAM modules (2GB each), brand new Optical Drive, a used known working Hard Drive, a brand new top case and keyboard/trackpad and a brand new battery.

The dim screen has pale yellow tint. Display calibrations in System Preferences aren't able to correct the color or brightness. Unchecking boxes in energy saver has no effect.

On startup the screen hangs for a bit after the dim gray apple screen with a pale yellow screen.

If I view the screen from above at a sharp angle, it is much brighter but still has the yellow cast.

When the Macbook wakes from sleep, the screen is very dim but gets slightly brighter after a minute or two.

Did I possibly get a faulty new LCD or Inverter? I reset the PRAM and then the SMC but no change in screen brightness. Or, could the Display Data Cable be faulty? I would think that if it were, there would be no data or screen image at all. Maybe a logic board issue?

The MacBook is running OS 10.7.5 Lion, 4GB total RAM, 320GB hard drive.

I'm ordering a VGA adapter for this machine, so may have more info after I can see an image on an external display.

Thank you so much for any insight on this .

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OK, since the screen image is bright and clear on the external display, this would seem to indicate that the logic board is not at fault. Next, to check into a possible defective new LCD, defective new Inverter or possible bad Display Data Cable. What else?

randy3833 의 2017년 7월 5일

try smc reset but seems more like cable or bad inverter issue

syed 의 2017년 7월 6일

Thanks you. I had reset the SMC and the PRAM without a change and have installed a brand new (or at least it was sold that way) Inverter. The inverter cable is new as well. It was in original packaging with a crisp 90 degree angle, So hopefully it's not at fault. The backlight issue is not intermittent.

randy3833 의 2017년 7월 12일

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Jon Ridley @thebookyard

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게시됨: 2017년 7월 10일

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Unfortunately, having a bright external display does not rule the logic board out as being a possible fault. the external display has its own power supply and backlight driver. the only data being sent from the computer is image data. So the fact that the external display is bright just indicates that your test monitor is working.

As for the fault with your laptop, can you please confirm a few things?

In the display preferences of the mac, can you see the brightness adjusting bar, or is it not present?

The possible causes of the fault are:

Logic Board.

Inverter Board.

LCD panel.

The only reason i'd suspect the cable is if it comes and goes, or if its affected by movement, or you have no backlight at all.

if its just dim, i'd look to trace the other items.

The logic board provides just voltage. so as long as the voltage is being provided as it should, then it wont be at fault. There is a backlight fuse on the board that protects against shorts or blowouts, but as you are seeing some backlight, that would indicate that the fuse hasn't blown.

I'd look to suspect that you've been sold a dodgy LCD initially, as that is the most universally accepted item. The inverter boards are made specifically for this range of mac, so are less likely to be altered or made by 3rd party companies, but LCDs are often built and adjusted by refurbishing centres.

Is there a white label on the back of the LCD panel indicating a model number of any kind? that early model of MacBook was usually shipped with one of 4 LCD brands, but the model number will help confirm if its actually compatible with your machine type.

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Hi! Thanks for your help! Yes, the screen brightness adjustment bar is there and set to full brightness. I had checked that a few times during this process

randy3833 의 2017년 7월 10일

The reason i asked about the display menu, is that i've seen unsupported LCD models that dont communicate with the logic board as they should not display the brightness bar. So its a good sign that its displaying the brightness bar.

Do you know the LCD model number from the back of the LCD panel?

Jon Ridley 의 2017년 7월 11일

Thanks Jon. That's interesting about the unsupported LCDs. I won't have time to work on the MacBook again for a few more days but will get the LCD label numbers and get back to you as soon as I am able to.

randy3833 의 2017년 7월 12일

Hi Jon, It's been awhile and a couple of vacations later, but I'm back on my project. I've disassembled my MacBook again and have the replacement LCD numbers. There are so many. B133EW0, A00001443018041530W00, EM8100504599-Z80101 and several other smaller numbers.

In my great wisdom and after going through Apple troubleshooting information for display issues, I came to the conclusion that the logic board must be the problem. I just replaced the logic board with a "brand new" one from eBay, and afterward have the exact same result. A dim display. I contacted the seller of my replacement display on eBay. He said that "A dim display is not a fault of the display itself" and asked about my inverter and cables. The Inverter that I installed was also labelled as "New" on eBay. A cable that I haven't replaced is the Display Data Cable. It seems to me that if I have an image on the screen, albeit dark, that the cable should be ok, right?

randy3833 의 2017년 8월 7일

The part number looks to be incomplete. The important one is the 'B133' number, as it identifies the manufacturers details. it is an AU Optronics panel that you have, but it should be B133EW01 for the early MacBook range.

You are right in assuming the data feed is separate.

The backlight of the display is run through the hinge cover to the left side of the logic, while the data goes through the right hinge.

The displays data goes from the LCD, to the LVDS cable to the logic board, and the backlight feed goes from the LCD, to the Inverter Board, to the Inverter Cable, to the Logic.

In my experience, the inverter cable is usually a culprit if you have intermittent backlight, or it cuts out with movement of the display. as it can get pinched in the left hinge. if the issue is brightness, the cable almost certainly cant be the cause.

Jon Ridley 의 2017년 8월 9일

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OK, since the screen image is bright and clear on the external display, this would seem to indicate that the logic board is not at fault. Next, to check into a possible defective new LCD, defective new Inverter or possible bad Display Data Cable. What else? — randy3833
try smc reset but seems more like cable or bad inverter issue — syed
Thanks you. I had reset the SMC and the PRAM without a change and have installed a brand new (or at least it was sold that way) Inverter. The inverter cable is new as well. It was in original packaging with a crisp 90 degree angle, So hopefully it's not at fault. The backlight issue is not intermittent. — randy3833
Hi! Thanks for your help! Yes, the screen brightness adjustment bar is there and set to full brightness. I had checked that a few times during this process — randy3833
The reason i asked about the display menu, is that i've seen unsupported LCD models that dont communicate with the logic board as they should not display the brightness bar. So its a good sign that its displaying the brightness bar.

Do you know the LCD model number from the back of the LCD panel? — Jon Ridley
Thanks Jon. That's interesting about the unsupported LCDs. I won't have time to work on the MacBook again for a few more days but will get the LCD label numbers and get back to you as soon as I am able to. — randy3833
Hi Jon, It's been awhile and a couple of vacations later, but I'm back on my project. I've disassembled my MacBook again and have the replacement LCD numbers. There are so many. B133EW0, A00001443018041530W00, EM8100504599-Z80101 and several other smaller numbers.

In my great wisdom and after going through Apple troubleshooting information for display issues, I came to the conclusion that the logic board must be the problem. I just replaced the logic board with a "brand new" one from eBay, and afterward have the exact same result. A dim display. I contacted the seller of my replacement display on eBay. He said that "A dim display is not a fault of the display itself" and asked about my inverter and cables. The Inverter that I installed was also labelled as "New" on eBay. A cable that I haven't replaced is the Display Data Cable. It seems to me that if I have an image on the screen, albeit dark, that the cable should be ok, right? — randy3833
The part number looks to be incomplete. The important one is the 'B133' number, as it identifies the manufacturers details. it is an AU Optronics panel that you have, but it should be B133EW01 for the early MacBook range.

You are right in assuming the data feed is separate.

The backlight of the display is run through the hinge cover to the left side of the logic, while the data goes through the right hinge.

The displays data goes from the LCD, to the LVDS cable to the logic board, and the backlight feed goes from the LCD, to the Inverter Board, to the Inverter Cable, to the Logic.

In my experience, the inverter cable is usually a culprit if you have intermittent backlight, or it cuts out with movement of the display. as it can get pinched in the left hinge. if the issue is brightness, the cable almost certainly cant be the cause. — Jon Ridley

MacBook Core 2 Duo

Why is my MacBook screen dim?

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