Mac Pro mystery - blinking front led light

[ositosucio]

hi guys...

I have a mac pro early 2008 with the 2 quad core 2.8 Xeon processors.

A few weeks ago something very strange started happening.

I would turn my computer on and it wouldn't boot. Instead I would get a front blink light. I immediately thought it was a RAM problem so I started moving RAM around to identify a problematic chip.

My current configuration is

top riser
2gb OWC-dimm4
2gb OWC-dimm3
2gb OWC-dimm2
2gb OWC-dimm1


bottom riser:
2gb OWC-dimm4
2gb OWC-dimm3
2gb OWC-dimm2
2gb OWC-dimm1


This is what I have found:
The computer will work and booth as if nothing ever happened ONLY when

a) bottom riser dimm 4 and 3 are unoccupied
b) I use the 1gb chips in those two slots that came with the mac originally

If I put any OWC ram in those slots they computer won't boot. I even bought another riser to make sure and I get the same thing.

Right now I am running at 14gbs because of this. I am positive is not the RAM as all the chips work when placed on other locations.


Any ideas or tests I can run?

I am kind of disappointed as I thought I would be running at 16gbs right now.


Thanks.

 

[Velin]

Actually, I do think it is the RAM. If you search my prior posts, I had this same exact issue. Blinking front red light, and as I recall, it was OWC RAM that went bad.

Pulled out the OWC Ram, no problem or issue.

I think you need to test with new RAM in the slots you think are problematic, and see if it boots.

 

[ositosucio]

Actually, I do think it is the RAM. If you search my prior posts, I had this same exact issue. Blinking front red light, and as I recall, it was OWC RAM that went bad.

Pulled out the OWC Ram, no problem or issue.

I think you need to test with new RAM in the slots you think are problematic, and see if it boots.

hello there...

I am sure it is not the ram because I did other two new chips from OWC and the problem continued. And all chips work fine if not using those 2 slots.

A bad chip would cause a problem anywhere it is installed correct?

 

[djjclark]

the riser has 4 little led's on it that will be red if there is a problem. I think a red light means one of three things - bad ram, bad riser, bad motherboard. You can narrow the problem down by changing ram around, changing risers around.

 

[ositosucio]

the riser has 4 little led's on it that will be red if there is a problem. I think a red light means one of three things - bad ram, bad riser, bad motherboard. You can narrow the problem down by changing ram around, changing risers around.

thanks I have already tried all my ram and another riser. The problem only happens as explained on my OP.

And no red lights ever from any of the risers.

thx

 

[Mactrunk]

I had a similar problem recently.
Suddenly, my 3 year old OWC ram started causing problems.
The good news is that they offer a lifetime warrantee.
They sent replacement sticks and 2 of those went out in a couple of days.
They replaced those and now all is well.
Running fine for several months.
Hats off to OWC for honoring the warrantee.
I think they are a great company.

 

[ositosucio]

I had a similar problem recently.
Suddenly, my 3 year old OWC ram started causing problems.
The good news is that they offer a lifetime warrantee.
They sent replacement sticks and 2 of those went out in a couple of days.
They replaced those and now all is well.
Running fine for several months.
Hats off to OWC for honoring the warrantee.
I think they are a great company.

I understand that but if the ram was the culprit, wouldn't i see those red lights light up plus if a ram chip is bad it wouldn't work in any slots right?

I have tested all of them and they all work if they are not in those slots.