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Released June 2012, Model A1278. Intel processor with Turbo Boost, Up to 512 MB DDR5 Video RAM

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MacBook won't boot - no chime - black screen - fans on high rev

Hey Guys,

my macbook pro won't start at all. If I push the on button, nothing happens despite status LED is shortly bright, then (0.5 sec) dim. There is no chime, no screen, no capslock led when pressed. And the fans rev like !&&*...till I power it off.

Tryed everything of the obvious solutions... PRAM /SMC / RAM swaps etc. ...nothing

Is it a failing logicboard or a power issue (the logicboard doesn't get the signal to turn on ? )

Anyone any idea?

thx ;)

Update (04/09/2018)

Still no luck :(

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I am having the same issue like you. No solution yet. This is third time I get. Last 2 times I tried PRAM reset and it worked. But this time no response from machine. Plz help with solution if you have any.

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Any update guys? I have the same issue and looking for answers

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Umashankar Harindranath Rao & promila.matta00 - If your system is reacted in the same way you need to replace the logic board as the CPU and/or PCH chip has failed.

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You may want to see whats going on with the thermal sensors & what the fan is doing. This is a good app to see them: TG Pro.

I haven't seen SMC get stuck on its own. But I have seen where I've needed to disconnect the battery to do a good hard reset can make the difference. Basically, disconnect the batter then hold the power button for a good 30 sec and reconnect the battery.

Update (04/10/2018)

Sorry guy sounds like your logic board is damaged here. If you can't start the system but your USB ports are working then you have a deeper problem within the logic board.

Did you get your system wet? Have a liquid spill or sit your system down on a wet surface at some point? These are often the cause. As the corrosive nature of what was spilled could slowly eat your logic board or cause a short.

The other possibility is a power surge damaged your system.

Update (04/13/2018)

Here's the IFIXIT guide you'll need to follow to replace your logic board: MacBook Pro 13" Unibody Mid 2012 Logic Board Replacement and here are your possible choices:

MacBook Pro 13" Unibody (Mid 2012) 2.5 GHz Logic Board Resmi

Ürün

MacBook Pro 13" Unibody (Mid 2012) 2.5 GHz Logic Board

$249,99

MacBook Pro 13" Unibody (Mid 2012) 2.9 GHz Logic Board Resmi

Ürün

MacBook Pro 13" Unibody (Mid 2012) 2.9 GHz Logic Board

$299,99

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So I can't boot, no chance to run diagnostics app :(

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Not even in diagnostic mode holding the D key?

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No, when I hit the power button, only fans Rev at full speed, no picture no gong. Only the LED is on and gets dim. When I close the lid, the led is bright.

Next thing I think could be a thermal sensor that is dead so that the board thinks it's too hot and fans spinning at top speed to prevent overheating ...but where are the thermal sensors on the i5 board?

If I plug in my phone it charges...means that everything with Power supply is ok?

Thanks Dan, no water spill at all. Today took the logicboard out and checked it under microscope...nothing to see...no corrosion or burnt components. I know that sometimes you not see If a component is dead...but the board is clean as he'll for the 5 year old machine ;)

Last time it was on...installing El capitan an then on the half or so I got "graphical snow" like on old TV at the screen and it shutted down. Is there a possibility that the installation tried to upgrade SMC or EFI and couldn't finish so that they are now corrupted?

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So now it's completely dead. Hitting the power button does not show white LED and the fans do not spin. Only HDD begins to spin and the MacBook will get warm. Charging and Battery indicator works ...also SMS reset. But does nothing :(

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Sounds like you'll need a new logic board as the 'snow' is a sign the GPU is failing.

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i seen this on another page.

Just fixed MacBook Pro stuck in Sleep and Fans running high. All you need to do is open up case and unplug the fans from motherboard! Somehow the temperature sensing must be in fan air and it senses high temp and shuts down computer with fans on high. Some how restarting computer doesn't reset things (design fault or firmware bug). But UNPLUG FANS and you're good to go. I did this while powered on and it sprang into life! Later I checked it powers down and reboots. Don't forget to plug fans in again before completion and fans "hey presto" run at normal speed. Apple engineers couldnt fix this and said we had to buy new board or computer $2k+. Good luck

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Thanks for the advice...will try it when home ;)

Update (04/09/2018)

Still no luck :(

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