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G5 Quad - Cannot Install OS X - Red LED 806

S

Sepultura

macrumors regular
Original poster
Jul 10, 2013
157
1
I have a Power Mac G5 Quad. It's the last model they made.

It has 9GB of ram. 4x2gb and 2x512mb.

Upon turning on the computer a red LED is on and then turns off. A few seconds later it's back on and stays on.

Looking into this, it's a ram problem. The led is labelled 'LED806.' It's below the top 4 DIMM slots.

The computer will turn on, chime, and the screen is black for around 8 seconds before it goes to the gray screen.

- If I just leave it, it will go to a 'happy mac' folder and stay there. It's a clean hard drive so it wouldn't boot anyway.

- If I boot the computer hold C with the Leopard disk in, it will go to the gray screen and stay there for sometime until it goes to kernal panic and says 'invalid memory access' etc.

- If I boot holding option, it will go startup manager but stay there for a long time frozen. Sometimes I can hit refresh and I see the Leopard disk. I try to move forward but it freezes again. Eventually it goes to kernal panic.

What puzzles me is this ram has always been used with the G5. The 2gb sticks are the same model and so are the 512. The G5 was running strong a few years ago with all this ram.

So is the ram dead or not? Could it be something else?

I tried testing the ram. 1 stick at a time and got 2 beeps and the fans went LOUD.

I tried 2 at the same time in the the same slots 1-1 and it the computer would just do the stuff listed above.

Thanks
 
It sure sounds like ram. I had a stick go bad about nine months after my boss bought my G5 back in 2005.
 
RAM sometimes fails, you know ;)
Testing one stick at time in G5 isn't a good idea. It needs matched pairs installed in corresponding slots.
 
Thats LED 7, which means the CPU is hanging. RAM can cause these problems, but an improperly mounted CPU can too. Also keep in mind RAM MUST be installed in matched pairs, so trying 1 stick at a time will never work in that machine.
 
Right I know the order from top down is 4-3-2-1 and 1-2-3-4. I knew it had to be matching but I thought you could do one stick.

I will try the ram and again report back.

Sure hope it's not the CPU...
 
Sepultura said:
Right I know the order from top down is 4-3-2-1 and 1-2-3-4. I knew it had to be matching but I thought you could do one stick.

I will try the ram and again report back.

Sure hope it's not the CPU...
Click to expand...

If it is the CPU reseating would fix it.
 
I don't think it's the ram. I just tired again.

2x512mb. Holding option to try to get to startup manager. It goes on with no red light, about a minute after it gets to startup manager red light is on.

2x2gb. Exact same outcome.

2x2gb (different set). Same outcome.

How do I reseat the CPU? It's behind the liquid cooler which looks like removing it could damage the board.
 
very few are talented and patient enough to remove this pin without damaging it.
Click to expand...
Ugh this doesn't sound promising...

I knew this was going to be a hassle. I will have to consider doing this now.
 
666sheep said:
Why not to use guide for Late 2005?
http://www.scribd.com/doc/21536787/...ad-2-5-Dual-2-0-2-3-Ghz-Service-Repair-Manual

Pin removal is easy, you just need right tool. I've never damaged one.

If it's not the RAM and CPU LED is still on, look for LCS leak.
Click to expand...

And what's the right tool? I used the one described in Apple's manual, and the pin is broken anyway. But it doesn't matter, the pin isn't necessary for the PowerMac, is just a way to know if it's been opened (for warranty purposes). But I guess yours isn't guaranteed anymore :roll eyes:
 
No obviously it's not in warranty anymore. It's long past that.

I just don't want to break anything, even the littlest of things. The computer inside and out is in great condition.

I don't see any visible leaks unless it's behind the G5 plating or back behind the logic board.

This is the last model and I believe they fixed that problem.

I don't see how that's related to the red LED.
 
You won't notice the pin isn't there unless you're looking for it. However, 666sheep says it's easy with the right tools...

It is related to the red light. The leak kills a CPU card and the G5 can't boot and shows a red light.
 
Andropov said:
And what's the right tool?
Click to expand...

Flat, sharp, thin and non-flexible blade. Exacto knife is too flexible IMO.
Something like this:
protouch-retractable-utility-knife-1115.jpg


Andropov said:
It is related to the red light. The leak kills a CPU card and the G5 can't boot and shows a red light.
Click to expand...

Basically this. CPU doesn't have to be completely damaged yet, and small leak is hard to notice unless you'll remove LCS. Read some more here: http://www.xlr8yourmac.com/systems/G5_CoolantLeak_Repair/G5_CoolantLeak_Repair_p1.html
 
Last edited:
My G5 does boot though. I just cannot install OS X and get a kernal panic if I leave it for a while.

The computer shouldn't even turn on if the CPU is dead?
 
I cannot get that pin out I am using a similar blade. All I am doing is chipping plastic off it. It's barely up and I do not want to break it.
 
can someone please do a video of this. I have nearly destroyed the top of the rivet and it's still not off. I do not want to break it.

I looked all over google and I only find dead links to guides.
 
OK. I am very impatient when I want to work on something and this forum moves slow at responding so I kept at it.

I got the rivet out and I think it's ok. I just mangled it really badly.

I got the side cover off and all I see is a ton of dust.

Again I don't see how this can be a problem if the computer is booting? I will proceed to the next step regardless.

Here are some pictures.
9271826573_f431a30ccf_o.jpg


9274615798_d15a7b6c49_o.jpg


9271825055_469109cd78_o.jpg
 
Ok now I am not so sure if it's worth removing this whole liquid cooler seeing how I could damage the CPU pins.

I really don't see any signs of damage.
 
Last edited:
Sepultura said:
OK. I am very impatient when I want to work on something and this forum moves slow at responding so I kept at it.
Click to expand...

You've confused forum with chat ;)
Impatience isn't a virtue, especially when you don't know what you're doing.
Things can only get worse with such attitude.

Get proper tools, study service manual from link I posted before, google "G5 LCS leak" and you'll discover that you have most prone to leak dual pump Delphi LCS. If leak is small enough to do not damage your computer yet, good for you. But you can't see it through LCS plate, can you?

Small leak (invisible through plate):
foto391pd0.jpg


Bigger leak (still invisible through plate):
DSC_2927.jpg


Big leak (visible through plate - too late :():
IMG_0824.jpg
 
Last edited:
Well I don't have either of the tools required to proceed to the next step anyway.

Looks like they go for $60-80 and have to be long-handled with a magnet... I could put that money towards a new computer.

I am going to try to borrow one but these look like uncommon tools.
 
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