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My Macbook pro has no backlight (you can see a dim image). I checked the backlight fuse on the logic board and it's burned out. I heard Apple recommends replacing both logic board and display to fix this issue, as the display be shorting out the logic board (so if I replace the logic board alone, the new logic board may get shorted out and damaged by the display again).

This way I may just replace the logic board without having to replace the display if it’s healthy.

How would one check the display pins for a short-circuit?

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    You found the advice why not use it. Or do you think you know better? – Solar Mike Feb 16 '20 at 5:08
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    I'm not sure what the question is here. If it's about wondering if you can check for a short circuit, well, the answer is "of course you can." But, just for our curiosity, do you know how? If you don't have experience in this area, I would advise you to seek the assistance of a electronics professional and not attempt this on your own. – Allan Feb 16 '20 at 5:23
  • Hardware problems of this sort need hand-on assessment by a competent engineer. Either take it to an Apple Store, or find a (decent) independent technician who works on Apple hardware. Any advice from the internet is likely to be generic. – benwiggy Feb 16 '20 at 9:35
  • I've edited the post. The question is if anyone knows of a way to test the pins on the display connector and so avoid having to replace it if it's healthy. – Antonio23249 Feb 16 '20 at 16:47
  • Thanks Allan. Rossmann’s videos are so long-winded I could never get a good insight on this backlight issue. What I need to know is whether the display is bad or not, not which element on the logic board is faulty. I guess the only fault on a display able to blow the backlight fuse would be a pin on the display connector (display-side) being shorted or having a low resistance. Apple’s official strategy is “if the backlight fuse is blown, replace both logic board and display, just in case the new display is faulty (shorted?) and blows the replacement logic board”. I’d like to find out what the – Antonio23249 Feb 17 '20 at 21:54
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How would one check the display pins for a short-circuit?

You don't know that this is the issue. What you do know is that you have no backlight.

I heard Apple recommends...as the display be shorting out the logic board

That's hearsay and not necessarily your diagnosis. Research is fine, but you need actual troubleshooting for a positive diagnosis. You wouldn't be pleased if your doctor gave you a terminal disease diagnosis if he/she didn't do anything but tell you "they heard from the AMA that...."

Just to give you a broad overview of what your looking for, there's no one diagnosis for a failed backlight. It could be

  • the backlight itself failed
  • a blown fuse
  • shorted pins

Each has their own diagnostic procedure like

To get an idea of this actual repair, take a look at this YouTube video. In the end, if this seems outside your wheelhouse, he's a good person to send your board to (not affiliated, just a happy customer).

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  • please check my answer – Antonio23249 Feb 17 '20 at 21:54
  • A few things to help you get acclimated.... First, Your answer shouldn’t serve as a reply. If you need clarification, leave a comment or edit your question. If you have further questions, ask another one. Secondly, and I can’t stress this enough, it’s not advisable to guess what the issue is. Until someone who has the resources to diagnose hands on you’re basically taking wild guesses. Finally, the Ohms value is on the schematics..Rossmans video’s tell you how to obtain them...it’s not trivial info. He’s long winded because there’s tons of info. – Allan Feb 18 '20 at 0:42
  • Also, your statement re: Apple’s strategy is incorrect. They don’t do board level repair and they have no idea what exactly the problem is so they replace all the possible faulty components; the logic board and display. There is no “short” or low resistance from the display that would cause this. – Allan Feb 18 '20 at 0:46
  • That's what I said Allan, please re-read my post. Apple don't repair at component level. I added an answer because the answer didn't admit so many words. And Yes, a short or low resistance on the display side of the backlight fuse would definitely burn it, that's what a fuse is all about. – Antonio23249 Feb 20 '20 at 19:24
  • A fuse doesn’t protect from a short. Low resistance doesn’t burn a fuse, either. You’re making assumptions based on faulty knowledge and a severe lack of empirical data. It’s prove by the statement “I’ve heard Apple...” which is nothing more than conjecture. I’ve given you a resource to get a proof positive diagnosis. You are free to accept/reject, but I won’t debate nor confirm what you’ve “deduced” the problem to be. – Allan Feb 20 '20 at 21:55

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