Mac Pro won't start up blinking light

Your profile was created when you were using 10.5.8, I hope that since then you have upgraded to 10.6.8 or above.

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Troubleshooting: My computer won't turn on

https://support.apple.com/kb/TS1367

Symptoms

If your Macintosh computer won't turn on, here's how to troubleshoot it. Please keep in mind that although your computer may display similar symptoms that prevent it from showing video, this article discusses what to do if the computer won't turn on, meaning that when you press the power button:

• You don't hear a startup chime.
• You don't hear any fan or drive noise.
• The power button or power indicator doesn't light up at all.

• You may hear a startup chime.
• You may hear fan or drive noise.
• You may see the power button or power indicator light up.

Resolution

If your computer won't turn on, try each of these steps:

1. Make sure that the power cord is plugged into a working wall outlet, and that it's properly connected to the power adapter. (To check if the wall socket is working, plug in a lamp or other electrical device.)
2. Make sure that the power adapter is properly connected to the power port on the side or back of the computer.
3. Disconnect all accessories that are plugged into the computer, such as a printer, hub, or other mobile device.
4. Reset the computer's PMU, SMC, or PRAM. Refer to the instructions for your model:
   
   • Portable (iBook or PowerBook)
   • Mac mini
   • iMac
   • Power Mac
   • Mac Pro
   • MacBook or MacBook Pro
   • Other Mac computers

Note: It is possible that the SMC could encounter an issue that may cause unusual system behavior typically related to the symptoms described below. In some cases, resetting the SMC may be the only correct method to resolve the issue,

https://support.apple.com/kb/TS1367

General purpose Mac troubleshooting guide:

Isolating issues in Mac OS X

Creating a temporary user to isolate user-specific problems:

Isolating an issue by using another user account

Identifying resource hogs and other tips:

Using Activity Monitor to read System Memory and determine how much RAM is being used

Starting the computer in "safe mode":

Mac OS X: What is Safe Boot, Safe Mode?

To identify potential hardware problems:

Apple Hardware Test

General Mac maintenance:

Reset SMC

http://support.apple.com/kb/HT3964

Resetting NVRAM

http://support.apple.com/kb/HT1379

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Install or Reinstall Mavericks or Mountain Lion from Scratch

the following procedure will remove everything from the hard drive.

OS X Mavericks- Erase and reinstall OS X

OS X Mountain Lion- Erase and reinstall OS X

OS X Lion- Erase and reinstall Mac OS X

About TimeMachine backups and Recovery Mode

http://support.apple.com/kb/HT1427

http://www.apple.com/osx/recovery/

OS X Lion and later let you:

Start from OS X Recovery using your Time Machine backup disk. With OS X v10.7.3 and later, Time Machine backs up the Recovery System on your Mac to your backup drive as well. This lets you use your Time Machine drive to start up your Mac if needed.

OS X Recovery:

http://support.apple.com/kb/ht4718

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Reset SMC

http://support.apple.com/kb/HT3964

Resetting NVRAM

Safe Mac Guide

http://www.reedcorner.net/mpg/

(MacPerformanceGuide is also an excellent web site for ideas on upgrades and optimizing for application type uses))

http://www.macperformanceguide.com

Mac OS X: Starting up in Safe Mode - http://docs.info.apple.com/article.html?artnum=107393

What is Safe Boot, Safe Mode? (Mac OS X) - http://support.apple.com/kb/HT1564

Isolating issues in Mac OS X

Creating a temporary user to isolate user-specific problems:

Isolating an issue by using another user account

Identifying resource hogs and other tips:

Using Activity Monitor to read System Memory and determine how much RAM is being used

Starting the computer in "safe mode":

Mac OS X: What is Safe Boot, Safe Mode?

To identify potential hardware problems:

Apple Hardware Test

General Mac maintenance:

Tips to keep your Mac in top form

How to install OS X on a new or faulty HD without Internet recovery

Corrupt and new disks might not have a working Recovery partition, but there are still ways to access one and reinstall OS X, if needed.

Leaves out features and support for what to do when you have a good TimeMachine backup that you can boot from, though I would also prefer and side with "prevention worth a pound of cure" and why I preach having a clone of your system from when it was working order. Note: if you have a functional TimeMachine backup and running Lion or later, you should be able to boot from there.

http://reviews.cnet.com/8301-13727_7-57594422-263/how-to-install-os-x-on-a-new-o r-faulty-hd-without-internet-recovery/

https://discussions.apple.com/docs/DOC-3353

It's designed for those who already have a good familiarity with how Mac's work, is almost all Apple support documented.

If it's too much for you, there are local PC/Mac software repair and data recovery services, for hardware repairs you should take it to a Apple Authorized Repair. Please read the disclaimers at the bottom.

This User Tip is designed for Mac's that are capable of running OS X Snow Leopard (10.6) to any Mac running OS X Lion (10.7) or Mountain Lion. (10.8)

The Steps appear to work also in OS X Mavericks (10.9) at this time.

approximately 2 per second

That IS a deliberate pattern, as opposed to random flashes of arbitrary duration.

That indicates "not enough working RAM to start up". If you were to remove all the RAM, you should get a very similar symptom, although the pattern may change slightly.

I am this exact issue today .

I hear no chimes at all , just a constant flashing light approximately 2 per second with no breaks in the pattern what so ever so there is nothing to count for a specific pattern . I tried some tof the various key combos at startup from Apple docs but nothing will get it to startup or get to a startup screen . I do feel some air flow so it appears the fan is on. I can't eject the drive bay to startup from a DVD. All the ram has been working in this for quite a while . It was working fine the other day and quite distressing as it's my main recording studio computer and I have a session in two days . Any other ideas to try ?

TIA, Craig

Late 2008 Mac Pro 3.1 , 8 core 2.8GHZ 28 GB ram 6 internal HDs.

OS10.8.5 is the default startup HD and there is another 10.6.8 startup on another internal HD.

Amazon has a 4GB kit for $25 (2x2)

AHT won't find every type of problem but the ASD CD might find more.

Apple's OEM memory had one year warranty.

FBDIMMs are easily the most sensitive due to how hot, and those cold-hot-cold cycles stress any electronics.

2x2GB FBDIMM DDR2 667MHz

http://www.amazon.com/BUFFERED-PC2-5300-FB-DIMM-APPLE-Memory/dp/B002ORUUAC/

667MHz are fine and will work - in fact you get ideal and more memory bandwidth from having all 8 DIMM slots filled which would cost $100 for all new.

I have 28GB of ram in there now all 8 slots are used . Six 4GB and two 2GB modules DDR2 6400 800 mhz and all have lifetime warranty. I did a memory test maybe 3 weeks ago and all passed then with Techtool pro. It seems like they all could not have failed and there should still be enough working ram in there to start up or is that not the case? If only one or two failed shouldn't I still be able to startup or would that affect all of of them in some way and hinder startup? Would the thing to do to be just start removing modules and and try starting up see if one of them is the culprit ? Four of the modules were added about 2 months ago maybe I should start with those?

Grant Bennet-Alder wrote:

approximately 2 per second

That IS a deliberate pattern, as opposed to random flashes of arbitrary duration.

That indicates "not enough working RAM to start up". If you were to remove all the RAM, you should get a very similar symptom, although the pattern may change slightly.

In the 2008 and previous, FB-DIMMs are installed in pairs in adjacent slots on the same Riser-card (except when you have only two, then they are in slot 1 on each riser).

A failure in one of a pair means neither can work. With FB-DIMMs, certain failures of DIMMs in lower-numbered slots CAN preclude the higher-numbered slots on the same Riser-card working correctly.

Well I removed them and tested them in pairs and one of the 4 GB modules did cause the problem so I am now back up and running with 20 GB minus the two 4GB modules pair so will see if I can get replacement for the bad one under the warranty . thanks !

colinpc-

Everyone else on this thread is discussing the Mac Pro 42 lb silver tower, which uses ECC FBDIMM memories in pairs.

While your MacBook issue is interesting, it is lost on the readers of this thread. Their computers do not operate on batteries.

On a Mac Pro 65lb silver tower, the power light flashing in a deliberate pattern indicates "not enough working RAM to start up".

You will need some "known good" RAM to make progress.

Ok thanks , then I guess I should remove them in pairs . Does it matter which pairs are filled ? Should slots 1 and 2 always be present and are they numberd ?

I had this same problem and just by removing the RAM boards, my battery was then able to charge. I then reinserted the boards and everything is fine.

Did you fix this problem? Would you share your solution with me?