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MacBook Pro 15" Troubleshooting

The 15" MacBook Pro replaces the 15" Aluminum with innovative features, such as an Intel processor, Magsafe power connector, and integrated iSight camera. Troubleshooting is fairly straightforward.

Note: This troubleshooting guide covers all original 15" MacBook Pros. The MacBook Pro 15" Unibody will be covered on a separate troubleshooting guide.

MacBook Pro won't turn on

Your computer will not boot.

RAM issues

If your computer beeps three times, there is a RAM issue. Either you have insufficient RAM to boot, or the RAM you do have is faulty. First, access the RAM slots (Core Duo, Core 2 Duo (Model A1211), or Core 2 Duo (Models A1226 and A1260)) and ensure you have RAM installed. If you have two chips, first reseat them and try again. If that doesn't work, try one chip at a time to see if one of the chips prevents the machine from booting. If none of these work, you may have a bad logic board.

Bad Left I/O Board

If your left I/O board is bad, you will not be able to start your computer when it's plugged into the wall. It may or may not run on battery and the light on the power adapter will not light up at all (some power adapters do not have lights, so this may not apply to your computer). These symptoms point to a left I/O board that needs to be replaced (Core Duo, Core 2 Duo (Model A1211), or Core 2 Duo (Models A1226 and A1260)).

We carry replacement left I/O boards for the following models: Core Duo, Core 2 Duo (Model A1211), Core 2 Duo (Model A1226), and Core 2 Duo (Model A1260).

Bad power adapter

If your battery is not charged, is completely dead or is removed from your machine, please make sure you are NOT using a 60W MacBook Magsafe adapter! A MacBook Pro is shipped from the factory with a 85W adapter and needs the full 85W to boot. The 60W adapter will keep a charged battery from draining but does not have enough juice to provide full charging functionality. If your power adapter is bad, the computer will run off a battery, but it won't charge. If your battery's charge is too low, it will be difficult to diagnose a bad power adapter. The easiest way to test this is to borrow either a battery or power adapter to test in your machine. If you have the same problem with another power adapter, your problem is most likely the left I/O board. If you have the same problem with a fully charged battery, you most likely need a new logic board.

Thermal Sensor Issues

If the fans run at high RPMs, but the computer does not boot, there is probably an issue with the thermal sensors. First, ensure that the thermal sensors are plugged in. If they are, try replacing the thermal sensors. If this does not fix the problem, the logic board most likely needs to be replaced.

Bad logic board

If the above steps don't fix your problem, replace (Core Duo, Core 2 Duo (Model A1211), or Core 2 Duo (Models A1226 and A1260)) the logic board. We offer logic boards for the following models: Core Duo, Core 2 Duo (Model A1211), Core 2 Duo (Model A1226), or Core 2 Duo (Model A1260).

Laptop shuts off when I unplug it

As soon as you unplug the computer from a power source, it shuts off

Dead battery

If your battery is dead, the computer will run fine off the power adapter, but will turn off when unplugged. A dead battery can manifest itself in many forms: It may not accept a charge (this particular symptom may also indicate a problem with the logic board), the computer may not recognize the battery, or the battery may be recognized as charged but fail to power your computer when the AC adapter is unplugged. We sell new replacement batteries.

Flashing question mark on startup

The computer displays the flashing question mark when it can't find a bootable operating system. This could be because your OS is corrupt, the computer doesn't have enough RAM, or your hard drive is failing.

Bad operating system

Try booting off an OS CD. Run Apple's Disk Utility and try to repair the disk. You could also try Alsoft's DiskWarrior. If this fails, reinstall your operating system. If you can, erase the hard drive prior to reinstalling the OS.

Not enough RAM

This is quite rare. If you have insufficient RAM for your computer to boot the operating system, you may get the flashing question mark. Installing (Core Duo, Core 2 Duo (Model A1211), or Core 2 Duo (Models A1226 and A1260)) more RAM or downgrading to an older operating system will fix this. You need 128 MB RAM to run OS X 10.0-10.4, and OS X 10.5 requires 512 MB RAM.

Bad hard drive

The hard drive may have been erased, corrupted, or damaged. If the hard drive has been erased, format it as HFS+ and reinstall your operating system back onto it. If it is corrupted or damaged, you need to replace (Core Duo, Core 2 Duo (Model A1211), or Core 2 Duo (Models A1226 and A1260)) it. Failing hard drives can display intermittent data corruption prior to failing completely. They often gradually get louder and start to click. If your hard drive is making abnormal clicking noises but still works, back up your data immediately and replace the hard drive. Any of our 9.5mm SATA hard drives will work in your computer.

My screen looks black, but I can see very faint graphics on it

Symptoms of this are a dark screen, but everything else seems to be running. If you get in close with a flashlight, you can usually see the image faintly.


If your backlight isn't working, the inverter may be bad. Other parts that may be bad are the display or the logic board. If your backlight fails intermittently while moving the display, the problem is with the inverter cables. Otherwise it is impossible to test for damaged parts without replacing them one by one. If you are comfortable taking apart the display assembly, replace the display inverter first, then replace the LCD. If you are not comfortable with this, you can replace both parts at once by replacing (Core Duo, Core 2 Duo (Model A1211), or Core 2 Duo (Models A1226 or A1260) the display assembly. We offer the following displays for sale: (Core Duo, Core 2 Duo (Model A1211), Core 2 Duo (Model A1226), or Core 2 Duo (Model A1260)). If this still doesn't solve your problem, you need a new logic board. However, you can generally rule out a problem with the logic board if you can plug in an external monitor and it works.

Other problems


If you lose firewire or ethernet, the only thing to blame is the logic board. Because there are many components of the logic board, many possible symptoms indicate logic board failure. Any one of these components can fail and leave the others intact. If you lose audio or USB on the left side of the machine, the left I/O board is to blame and must be replaced (Core Duo, Core 2 Duo (Model A1211), or Core 2 Duo (Models A1226 and A1260)). Loss of USB on the right side requires the replacement of the logic board. If you lose the use of another component of your computer, such as the display, battery, or even power, and replacing the apparently non-working part didn't fix the problem, it is possible that the logic board may need to be replaced (Core Duo, Core 2 Duo (Model A1211), or Core 2 Duo (Models A1226 and A1260)).

12 Comentarios

High-pitched whine may be caused by the inverter board, not by a faulty fan. Does iFixit sell such boards for Macbook G4 Al 15 inch models?

burkbraun - Contestar

If you'd like replies to your comments go to Answers!

originalmachead - Contestar


Section one : i have a macbook pro mc375.

when i power on my laptop, dvd drive has not working.i go to macintosh os & insert the dvd disk, but dvd drive not working.

Section two : reset my laptop and start again.when the system is startup i insert the dvd drive Immediately and dvd drive has been starting on and be working.

**just when dvd drive is working that i insert the dvd disk in startup page.if i don't do this dvd drive not working.**

thanks again...!

Best regard...Arash Shabani

Arash Shabani - Contestar

Ask this as a Question - It's not a note.

originalmachead -

Hi there,

just wanna make sure its the left IO board i need to replace before I do it..:)

macbook pro A1211.

The problem is with the audio. there's no sound coming out of speakers and inside the headphone input i can see a red light.

However when i reboot the laptop, i does play the mac startup sound..

In preferences menu under audio/output it shows optical digital out port. nothing else..

When i plug in headphones output menu switches to "headphones" and I do get sound in the headphones.

I guess its the left board isnt it? If so where do you recomend buying it since im in denmark..

Oh an buy the way:

is there an easy way to remove the cd drive and move the existing HD to cd drive place and install a small SSD at the original location of the HD?

So I would have an ssd for apps and HD for storage. Will that work on such an old laptop and how complicated is it?


Nurali (

Nurali Kushkov - Contestar

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