Red light on Mac Pro memory board

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Level 1

1 points

Red light on Mac Pro memory board

I was working to eliminate a buzz in my Mac Pro today. As I was doing this, I noticed that there are red lights (looks like 4 per board) on the memory boards that flash as they start up. After start up one of the lights remained on.

I changed the order of the RAM on that board (I had just added Crucial Memory to the system a few weeks ago). At that point, the light no longer stayed on after startup.

Any ideas on what those lights mean? I assume it's a warning of some kind.

I had not noted any problems with my system operation...

Mac Pro, Powerbook G4, Mac OS X (10.4.8), 3 GB RAM (1GB Apple, 2GB Crucial)

Posted on Nov 11, 2006 8:24 AM

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Answer 1

Best reply

capnhack

Level 1

85 points

Nov 11, 2006 11:33 AM in response to dj coffey

yea the lights show problems with the ram. ecc errors usually dont make the lights turn on, you have to use system profiler (or another app) to check for those, but if the ram isnt seated properly or has some form of hardware problem which could cause more serious problems then the light will come on for the dimm.

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Answer 2

Magian

Level 1

9 points

Nov 11, 2006 1:15 PM in response to dj coffey

I recently had the same problem. I have 2 x 512MB on Riser A and 2 x 512MB on Riser B. One of the modules on Riser B was showing a huge number of ecc errors and on opening the case i saw that a red light was on for that DIMM.

I reset the machine and Riser B disappeared from the system profiler. The memory module that was showing the ecc errors had blown. I have a new module now from Apple and all is well.

I would return that module or better still the pair if it is giving problems and a get replacements.

M

Mac Pro Mac OS X (10.4.8) 2.66, 2GB, X1900, BTAP module, Black Macbook

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Answer 3

dj coffey Author

Level 1

1 points

Nov 11, 2006 3:22 PM in response to dj coffey

I was working to eliminate a buzz in my Mac Pro
today. As I was doing this, I noticed that there are
red lights (looks like 4 per board) on the memory
boards that flash as they start up. After start up
one of the lights remained on.

I changed the order of the RAM on that board (I had
just added Crucial Memory to the system a few weeks
ago). At that point, the light no longer stayed on
after startup.

Any ideas on what those lights mean? I assume it's a
warning of some kind.

I had not noted any problems with my system
operation...

Well, I reseated the ram in the risers and no more light. I haven't seen any ecc errors, so I guess all is good.

Thanks.

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Answer 4

Nov 22, 2006 6:16 PM in response to dj coffey

Hello,

i just got my new MAC PRO Today.
And ****. the lower one shows the red light and in the sys profiler the ram modules do not show up thx!

Benjamin

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Answer 5

andyrew

Level 1

5 points

Dec 1, 2006 1:12 PM in response to Benjamin Spiegel

Hello,

i just got my new MAC PRO Today.
And ****. the lower one shows the red light and in
the sys profiler the ram modules do not show up thx!

First day I had my MacPro, I looked to System profiler to find that only 512MB of RAM was listed.

I opened the case, removed Riser A, then re-seated Riser A

Hardware Overview now shows 1GB memory...

MacPro 2.66 Mac OS X (10.4.8)

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