LCS Issues Late 2005 Quad

Check the "Energy Saver" section of System Preferences, and turn the Processor Settings to reduced. Also, running thermal calibration would't hurt. To fix this issue completely, a LCS overhaul would be recommended

 

To run the thermal calibration you'll need the proper ASD disk, which is available here in my DropBox.

 

It looks like one cpu is running a lot hotter. You could try disabling it, but if you want all 4 running well it looks like it could use some work. Nice find btw!

 

Do you have a fan laying around? My Quad does the exact same thing, I put a fan in front of the computer and it passed

 

All Quads have Delphi LCSes, yours is a dual pump, which I am pretty sure is the less reliable version. The fan thing should work. It seems crazy, but it actually will make it pass

 

Ok try and move the Quad into a colder room, then see what happens

 

Or open a window? It's freezing where I'm at.

I don't own a G5 but I've seen a few different threads on servicing the LCS. It doesn't look too terrible to work on from what I've seen people post.

 

You could buy a whole new processor and LCS unit off eBay, but it may have the same problem as the LCS probably hadn't been serviced. The easiest thing is to bring the LCS/Processor assembly to a professional if you aren't comfortable doing it yourself

 

I think the G5 units that were manufactured earlier had problems but I am on my second Quad and this one also has no issues. Perhaps the seller you bought it from had it laying on its side while in operation? Because the picture of the LCS looked fine and I didn't see evidence of leaks.

 

I'm willing to bet that the machine was stored on its side and not used for a while which then resulted in either a failing of only partially working pump for CPU A. If anything, disabling that CPU and running it a s a dual 2.5 would make it so that you could still use the machine.

That's what I'm actually doing right now with CPU B disabled and the CPUs running in reduced power mode. I don't know how to disable CPUA since I think that's the default CPU though.

As far as a test to check the pumps I don't know. I have a question for you though, do you see any evidence of cracks in the tubes? I know just from dealing with any issues from any system that requires liquid cooling that the tubes can crack from either decreased use or over exposure to the environment due to improper storage.

And I wanted to say that the thread you read (which is awesome) also shows what you probably shouldn't do when it comes to altering the hardware designed and used for Apple's machines. What the OP did was creative, but it is also very possible that he was just using his Quad for too long with too much demand that caused his computer to eventually fail. I'm pretty sure there have been quite a few G5s and Mac Pros from Disney that have bad CPUs due to the high demand put on them.

Not to say that it's not worth saving, but having a machine running hard for 10 years is awesome in itself.

 

I would look right behind the seals to see if there are any cracks or at least evidence of the hoses being dry. There might not be any leaks per se, but the system is pressurized so any air at all in the system would cause temperature anomalies and cooling issues.

With any liquid cooling system, improper storage leads to problems just due to the nature of the liquid used to cool the system. Coolant in general is corrosive so it sitting in one spot or area in the system and not being circulated can cause issues.

I just think that it was stored improperly to the point where coolant stayed in the pump and what might be causing the pump to not pump it fully or in the off chance that the coolant has clogged part of the pump. After all, if the pump just wasn't working then the temps for CPU A would be crazy and that CPU would most likely be dead soon.

Yes there are but they are not cheap. If you do decide that replacing the LCS is the way to go, then I would forego using the coolant normally used and instead use mineral oil. It's not corrosive, not conductive, and can handle high temperatures.

 

And just so you know, I would ALMOST kill for that GPU. I have been looking for one and I have not been able to find it for a good price at all. Especially since my finances are extremely limited I am very jealous. It makes sense though if that was used as a production/editing machine for a while which might also explain why one of the CPUs is possibly overheating.

 

It does look like that and that I think is normal given the age of the computer and what it was most likely used to do. Could you zoom in on the top pump and the hoses? Something looks weird right after the seal and it seems like the clamp is a little tight on it unless that's just the angle of the photograph.

Do you have the developer tools installed? If so you could always enter the following command and see if it helps: "hwprefs cpu_disable 2"

This will disable the 2nd CPU and leave CPU1 and of course CPU3,4 active. I'm just hoping that if you disable the 2nd CPU and leave the 1st core with only one CPU active, then the pump (if there is an issue with it) will work better to cool it.

And I'm not sure if there is anyone that does but if they're not in your area, then that would make it really expensive to ship there and back AND pay for the service.

 

Yes there is but you have to disassemble it. Do you want the service manual?