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MacBook Pro won't start and beep three times sometimes

Hi,

I have a MacBook Pro 15" from 2010. It used to work fine, but all of a sudden when I tried turning it on one day it wouldn't start up and give me three beeps. I knew this could be a RAM issue, so I reseated the RAM, after which it booted fine again. A day later however the problem returned. This time reseating the RAM didn't do the job. I assumed it was faulty RAM so I ordered a new stick of RAM. Once I got it, I replaced the old one, but the MacBook would still beep three times. After several attempts I got it to boot with the new RAM.

Up to this day, it will almost always beep three times and not boot, although sometimes it will boot. I am absolutely clueless, because an issue with the RAM modules seems ruled out. Does any of you have any ideas what the problem might be? Thanks.

Answered! View the answer I have this problem too

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OK the three Beeps are a RAM issue, as you already know. You are correct, and did the right thing.

Now you need to test if a slot has gone bad or partially bad.

Remove the RAM, use canned air and blow the slot out.

Take one stick only, try it in both slots to check out both the RAM and the slot.

Now you have known good or bad sticks or known bad slot.

If the slot, try loosening the screws that hold the slot in place - crazy, I know but it can work.

Test again.

If RAM is bad, trash it.

If slot is bad, use the screw solution or sometimes it will take a lessor stick (if you have one).

If not live with one stick, the highest your machine will take. ( a 4MB)

RAM Type: PC3-8500 DDR3 Min. RAM Speed: 1066 MHz

Standard RAM: 4 GB Maximum RAM: 8 GB

In the past I have found, after many days of trail and error, that the RAM may have had ESD damage and cause erratic behavior. Work one day and not the next. Unless you are a Professional the time spent discovering this is nauseating. To test it you need a program like Atomic by Micromat: http://www.micromat.com/store#atomic

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Thanks for the reply mayer. I have already tried blowing it out with compressed air and trying each stick of RAM seperately in both slots, but with no avail. None of the possible set-ups are guaranteed to work; sometimes it beeps, sometimes it boots. I'll try the screw trick. Any thoughts on why none of the possible set-ups works??

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I got it to boot again just now, but now the screen would start to flicker with a bunch of coloured horizontal lines and then it black. What could this be?

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You were answering while I was still editing. Now you have new symptoms and I question if your identification of your machine is correct because this sounds like an issue I know with another machine. Symptoms change, thus does the diagnosis.

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How do you mean the identification of my machine is not correct?

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You started with a RAM problem and now have video issues. Video issues are known to exist on these machines:https://www.apple.com/support/macbookpro...

Please go here and enter your serial number to correctly identify your machine,

http://www.everymac.com/ultimate-mac-loo...

It's way past my bed time so I'm going to have to continue in the morning.

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