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2.3GHz, 2.6GHz, or 2.7GHz quad-core Intel Core i7 processor (Turbo Boost up to 3.7GHz) with 6MB shared L3 cache.

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No Video Signal, No Power to Screen or apple logo on the back. Help!

Hi,

My MacBook Pro recently decided to completely disable video signal and now there is no power to the screen or the logo on the back, no HDMI or Thunderbolt. The only way to view screen is via AirPlay or ScreenSharing.

1. My HDMI was showing no signal for the last few months, didn't bother me since I don't use HDMI.

2. When using screen sharing and AirPlay I can see my system is working perfectly, this tells me GPU is just fine.

3. There is no video output in HDMI, Thunderbolt and screen doesn't power up, this tells me it's not a screen, but something that detects video output and sends power and image to the screen.

PRAM and SMC resets, booting in safe mode, etc didn't give me any results. When hard drive is out, screen wouldn't power on anyways, so sounds like not a software issues. Can't run diagnostics because screen is off and I can't see any results.

There seemed to be a repair program by Apple until Dec 2016, but I didn't have issues back then.

System is a MacBook Pro Mid 2012 Retina 15"

Is there a specific part is most likely to be the culprit. Used logic boards are around $700 and I am not even sure if it will fix it.

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Yury Usanin start by disassembling your MBP and lets take a look at both sides of the logicboard. Check for any obviously damaged looking components as well as your display adapter. Post some good images of your board etc. with your question. Use this guide 在已经存在的问题里加入图片 for that. It will allow us to see what you see.

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Yury - I would start off by checking the display using a flashlight shining it though the Apple logo. Basically the flashlight is replacing the backlight of the display. The fact the Logo is not lit could be a simple issue here but you need to see if you can see the faint images or your desktop and the icons on it using the flashlight as @paperboypaddy Padraic had recommended.

If you can't see the desktop then the internal display its self is having issues. Did you bang or have something heavy sit on the display? The other possibility is liquid damage where the internal display is connected to the logic board. You'll need to pop off the bottom cover to check that out.

You also talk about the HDMI & Thunderbolt connections not working this could be a blown chip and its possible the power feed for that part of the logic board is damaged which is also effecting the display. You'll need to do a detailed inspection of the logic board referencing the images in this IFIXIT guide: MacBook Pro 15" Retina Display Mid 2012 Logic Board Replacement to compare to your board. If you see something take a good set of pictures and post them here for us to see.

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Have you tried the flash light trick? Hold a flashlight right next to the screen and turn it on. If you see the desktop of you account then the backlight is bad.

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Yes, I tried that. There is nothing on the screen, there is no power to apple logo.

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Ok. Hmmm. By the way I’m pretty sure that the Apple logo is lit be the display backlight. Have you checked any of the connectors inside of it?

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no didn't dig into display yet, primarily because HDMI and thunderbold don't work either so suspect something common between the 3.

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Well it’s $499 for a new logic board.

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Sounds to me like a component on the mb is possibly bad. At this point i would definitely say mother issue. Are you getting a light on the safemag? Could be an smc problem. and the fans spinning? Does it do anything when connected to power?

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He said it’s just the display! It works if he uses airplay or screen sharing.

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Yes ,laptop runs and I can stream the screen on apple TV or via vnc... so it is the video output, but because screen is stream-able, I doubt it's GPU.

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You have a problem with a logic board. I believe there is one chip that developed dry solder joints.

Will the computer freeze if you change to the discrete GPU? Do you perhaps get a keyboard backlight to turn on when it fully boots?

Try closing the lid and waking it after 20 seconds, if perhaps you get the picture.

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I did exactly that. I would close the lid, wait for a minute, reopen and it worked. Now it completely stopped showing anything on the screen. If I pull hard drive, boot from a flash, drive, etc, I can't see a logo on the screen or a loading bar, nothing. Even the low level bios is not enabling the screen, hdmi or thunderbold.

But laptop itself runs fine and can be viewed via vnc or AirPlay, so most likely not GPU.

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Well, if problems began like that, so that you had to open and close the lid to get the screen to light up, then this confirms my assumption of a logic board problem. Also it would usually freeze when you start a program that requires an eGPU, as it would try to switch it back to eGPU and fail doing so. This is exactly the why Apple had the logic board replacement program for these models.

This machine has two GPUs, external and internal. When it boots, it runs the picture through the eGPU, but when you get to the login screen, it switches it to the internal GPU.

If you access the laptop via a AirPlay or other remote means, you bypass the GPU entirely, at least when it comes to showing the picture on display. You might have be able to get it to freeze if you switch it to eGPU via Energy Saver in System Preferences by disabling Automatic graphics switching.

Try this and report back. Good luck

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