Macbook pro no start chime black screen

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Macbook pro no start chime black screen

I recently replaced the motherboard of my macbook pro. I'm sure nothing went wrong here. The old motherboard broke because a part came off, not due to water damage.

When I turn the macbook on there is whirring and the front light appears but there is no startup chime and the screen remains black. I have tried SMC and PRAM reset- nothing. I have also tried attaching an external monitor and nothing appears there either.

Could this be a CPU issue or something else?

Is there a way to fix this without buying a whole new motherboard?

I think it is an A1278 logic board.

I'm told it was working on IOS Snow leopard.

Many thanks in advance.

M

MacBook Pro

Posted on Nov 7, 2015 3:36 PM

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Answer 1

leroydouglas

Level 10

200,172 points

Nov 8, 2015 3:52 AM in response to Alphedetti

When you press the power button on your Mac, the first thing that happens is the Mac's hardware is initialized and the firmware -- BootROM -- is loaded and run. The BootROM is stored on flash memory chips on your Mac's logicboard, and it works as a miniature operating system to get things started before Mac OS X is loaded.

At power on, the firmware runs the Power-On Self Test (POST), which tests the processors, system memory, and network (Wi-Fi, Ethernet) and peripheral (USB, FireWire, Bluetooth) interfaces. If your hardware passes the POST, the startup chime is sounded and a light gray background is displayed on any attached display.

So what happens if your Mac doesn't pass the test? You hear no chime and the display either remain blank or off, or you might see error codes displayed.

Intel-based Mac Power On Self Test RAM error codes - Apple Support

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Answer 2

Alphedetti Author

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Nov 8, 2015 3:54 AM in response to leroydouglas

Thank you, I will ensure everything is connected and try again, but is there any way of identifying exactly what is preventing the hardware passing the POST?

Many Thanks

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Answer 3

leroydouglas

Level 10

200,172 points

Nov 8, 2015 10:00 AM in response to Alphedetti

Alphedetti wrote:

Thank you, I will ensure everything is connected and try again, but is there any way of identifying exactly what is preventing the hardware passing the POST?

Many Thanks

Are you getting any other response- power LED on the front of the computer or tones??

There may well be tools for testing the board but this would require Apple or Apple Authorized Service Provider insight beyond me.

If all connections are secure, of course my first thought is a bad board.

Is there a guarantee on the purchase of the logic board?

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