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모델 A1278, 2012년 6월 출시. Turbo Boost가있는 Intel 프로세서, 최대 512 MB DDR5 비디오 RAM

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Black screen and fan revs no chime

My macbook pro 2012 turns on but shows no display and all i can do is see how much battery life it has and hear it rev up the fan like a engine, i can only hear the fan revving up would that mean my logic board is stuffed?

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I have fixed this problem before where the fan goes loud with black screen.

I had to get rid of a short that was on the logic board (I made it with solder accidentally)

Then it worked after that.

Can you please explain what you did please

Thank you

@Dwl Me can you explain what you did to fix it? Like what you did on the computer? Thanks a lot this will help a lot

Im having same problem how do i do?

@Dwl me howndid u do it?

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선택된 답변

Connect the power adapter to the Mac. On the MacBook / Pro's keyboard, hold down the Shift+Control+Option keys and the Power button at the same time. Release all keys and the power button at the same time – the little light on the MagSafe adapter may change colors briefly to indicate the SMC has reset.


We need to know exactly what it will do. I would hook it up to an external monitor to try to isolate the problem. What dos it do when you reset the PRAM?

Here's how to reset your PRAM:

Shut down your machine. Yes, all the way down, not sleep or logging out.

Press the power button and then press command-option-p-r. ...

Hold those keys down until your Mac reboots again and you hear the startup chime.

Let go of the keys and let your Mac reboot normally.

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Have already tried that and also resetting the PRAM

External monitor shows nothing and resetting PRAM does nothing at all

Hi, I've been having a similar issue in my mid 2012 macbook pro but I get the chime and the screen stays black and the fans sometimes over throttle. It happened yesterday too but it had somehow started working eventually, pls help!!

my MacBook pro mid 2012 is turning fans only. the screen is black when i press caps light is off. it seems the laptop is off, only fans is on. What can i do

hey jonaijumba pls help me, i have the same problem in my imac 2009 model,pls

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I had the same issue with my 2013 macbook pro. I plugged the power cord in, and the fans would spin up, stop, and then continue doing that. I tried all the commands. What worked was disconnecting the power cord, holding down the power button, then connecting the power cord. The fans spun up, chime occurred, and I was able to use the computer!

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This worked for me, holding down the power button while I disconnected then reconnected power cable, I held it for 15 seconds after I reconnected and bam it was up, please note: I also had the case open with the battery disconnected while doing this on my late 2012 MacBook Pro 13 inch

Just posting to say that I tried everything else in this post and this ended up working for me as well. I'm not suggesting that the other posts didn't help, but I believe that this was the final step needed. Thank you!

I have a MacBook Pro a1425 and it has similar symptoms. When I connect the power adapter, the fan would spin and then stop, doing this continuously, the screen in black.. I tried to reconnect the battery, but nothing happen.

The machine was liquid damaged, and I think the keyboard is fried. Should I replace the keyboard first?

Pretty sure the fan spinning intermittently and the fan spinning continuously are symptoms of different issues. I tried every thing on my 2012 15" but skepticism made way for relief after succeeding with this solution - Thanks Andrew Wartman :)

I tried this as a last resort. I already planned visiting a logic board expert but like magic, it worked. Thanks a million

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If it is not chiming, it means it is not passing POST checks. Try booting it with the battery disconnected. It most likely is the logic board signal ppvcore_s0_cpu, so check that out as well if you have a multimeter (you will need to get a board view and schematic for 820-3115).

Most likely is a logic board issue, possibly dead CPU or voltage leading to the CPU? Check the board for liquid damage as well, and clean if it is present (but note the areas effected).

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댓글 16개:

I think it's water damaged but i've tried cleaning it with apl alcohol and the same thing still accures, It shows no display on anything and even without the ram and hdd in it makes the same reaction no matter what i do

Press the caps lock key about a minute after pressing the power button, does the caps lock light up? If so, it is more likely an issue related to the LCD circuit, and the fan spin can be caused by a sensor (for example, bad trackpad can cause this). Have you tried outputting the image to a TV/monitor via cable, to make sure it is still booting fine? Can you add a picture of the area where it was liquid damaged? You may need to take it to someone who has an ultrasonic cleaner, in case there is liquid under any ICs

External monitor shows nothing on screen, ill try the caps lock method but i dont think it will work

Ok. If the caps lock key does not light up, it means this is not getting into an OS. Due to it not chiming either, it is not passing the initial checks as I though, so it will be a more complex fault on the logic board. You can replace this which will resolve the issue, or take it to someone who can diagnose and repair the logic board (if possible, could even be a dead CPU)

FYI, newer MacBook Pros don't chime after POST any more, so not hearing a chime doesn't mean a problem. Really, the only way to confirm POST in a no video situation is to see if caps lock responds.

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You'll need a hardware bypass on the grey screen to permanently disable the GPU. Some software fixes work for a while, but it always comes back. You can even have the GPU reballed and it will work for a while, but overheat again and return. The only "permanent" fix is to jtag the unit using dosdude1's method. Or, you could bypass it using RealMacMod's method. Both are found in Google. I've done several and both involve, either soldering wires to pads to jtag code onto the logic board. Or, software and a jumper cable to bypass and keep the sleep function working. Either way, you're faced with making the system believe that there is no other graphics processor but the onboard intel gpu. It was an Apple recall to replace the Radeon gpu, but even after replacing it, they still eventually failed. I stay clear of that year, but MadMod is only 30 minutes away from me. So, if I do get one in, I let him do it for me for a modest price. You can buy that software on his site, but without the physical bypass, it's only a temporary fix, until you clear the PRAM or NVRAM.

As far as the top question, I’ve had luck with turning off the unit, taking the battery out. Hold down the power button for about 30 seconds, the apply power by the power supply while holding down, Continue to hold down for another 30 seconds. Let go of the power button. It should start up after you push the power button after letting go. The fans will be on high, but let it boot all the way through to the home screen, if it makes it. Then do a normal shut down, allowing it to spin and write it’s exit code. Wait a few minutes, then restart normally. The fans should spin up, but then return to the normal state. You can also start up in safe mode by holding the shift key down all the way through the boot procedure. It’s really a bad instruction set at boot that needs to be re-written (kext) from my experience. Getting it to boot all the way through is paramount in rewriting the exit code properly. It’s a trial and error thing, but that has worked for me in the past. I’ve also used the system boot USB drive, to boot from and run diagnostics on the board. Removing ram and changing the ram amount or configuration will force it to re-examine the parameters of the board and environment. This has also worked to force it to boot slow writing a new kext file to return the fans and logic board state to normal. Good luck.

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So.. I think I’ve f-ed up. I’ve done this method and it worked. But then it started opening programs I had opened when it froze (maybe 3 months ago) but it froze again so… the idiot I am, I’ve naturally did the hard shutdown. And now even this method doesn’t work. Would unplugging the battery and letting it sit for a while and then trying again would work?

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In my case it was a problem with the I/O board. After unplugging the board and rebooting the computer started working.

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