G5 aircooled 2.7

[imactheknife]

I have attempted to aircool another one of my 2.7. I bought it will nasty leak lcs and not sure if she worked. I did the exchange after cleaning everything up properly. It booted but would go to sleep during boot. Never seen that happen. Once booted she seemed to act little more normal. Now she sleeps a lot and temps say 40 or so on one cpu while other says over 100! Anyways, ran asd 2.5.8 and calibrated the cpu while the old lcs was plugged in. It passed fine. I ran stand alone tests and cpu b didn’t pass ammeter test. Alarm bell 3?! Or something. Is this one dead?

 

[Nixontheknight]

I have attempted to aircool another one of my 2.7. I bought it will nasty leak lcs and not sure if she worked. I did the exchange after cleaning everything up properly. It booted but would go to sleep during boot. Never seen that happen. Once booted she seemed to act little more normal. Now she sleeps a lot and temps say 40 or so on one cpu while other says over 100! Anyways, ran asd 2.5.8 and calibrated the cpu while the old lcs was plugged in. It passed fine. I ran stand alone tests and cpu b didn’t pass ammeter test. Alarm bell 3?! Or something. Is this one dead?

if it doesn't pass a test, it's surely dead, try getting a 2.5GHz G5 and overclocking it to 2.7 if you cannot find another 2.7 G5

 

[imactheknife]

I have an extra 2.5 processor. Cant plug that in beside it the 2.7 i would imagine?

 

[beachycove]

A bad job of applying heat sink paste could give that result. The G5s are hard to get right — I have done the job often, and have needed to repeat the process two or three times over the years because of high temps after the first go.

So it might be worth pulling it apart one more time….

 

[imactheknife]

A bad job of applying heat sink paste could give that result. The G5s are hard to get right — I have done the job often, and have needed to repeat the process two or three times over the years because of high temps after the first go.

So it might be worth pulling it apart one more time….

If i switch processors around i dont get any chime. Not sure if they are slot specific? I tried the processor in another g5 2.7 and it did the exact same. will try again. I stuck a 2.5 g5 card in it, and she boots but shows a 2.7 not 2.7 which makes sense obviously, but she works beautifully with a singlr

 

[imactheknife]

If i switch processors around i dont get any chime. Not sure if they are slot specific? I tried the processor in another g5 2.7 and it did the exact same. will try again. I stuck a 2.5 g5 card in it, and she boots but shows a 2.7 not 2.7 which makes sense obviously, but she works beautifully with a singlr

Should say not dual 2.7 above.

 

[beachycove]

Switching processors would require thermal recalibration, but it ought to boot with fans blasting after the switch if the processors are both working. Sounds like a serious hardware fault.

 

[Byrd]

if it doesn't pass a test, it's surely dead, try getting a 2.5GHz G5 and overclocking it to 2.7 if you cannot find another 2.7 G5

I didn't think you could overclock G5s one little bit, especially with switching processors?

 

[Nixontheknight]

I didn't think you could overclock G5s one little bit, especially with switching processors?

I've never used G5s (I hate them because they run way too hot and fail too much for my taste, but somehow I like the MDD G4s), but I would assume that you can, I think Hrutkay Mods did that, but I'm not too sure

 

[Romko23]

Ok, here is a weird issue - I also have a PM G5 Quad.. never an issue at all, except now - So, when I try to boot into the Diagnostics the overtemp light goes on, and another one goes on also. But, when I am in Leopard, or Sorbet I can run everything and even under heavy load and the machine does not shut off. I checked with flashlight the processors and pad under neath - nothing leaking at all. I hardly use it. What could be problem if I can use it when in Leopard, but when I try to boot the diagnostic EFI version, not OS version.. it won't go past that.

 

[imactheknife]

Ok, here is a weird issue - I also have a PM G5 Quad.. never an issue at all, except now - So, when I try to boot into the Diagnostics the overtemp light goes on, and another one goes on also. But, when I am in Leopard, or Sorbet I can run everything and even under heavy load and the machine does not shut off. I checked with flashlight the processors and pad under neath - nothing leaking at all. I hardly use it. What could be problem if I can use it when in Leopard, but when I try to boot the diagnostic EFI version, not OS version.. it won't go past that.

What version of diagnostic are you using? You need 2.6.8 or something like that. It takes a few minutes to get cd booted up too

 

[Romko23]

What version of diagnostic are you using? You need 2.6.8 or something like that. It takes a few minutes to get cd booted up too

Hi, 2.6.8 is what I use.. this version also works with my PowerBook G4 DLSD. OK, so when I run the thermal calibration the lights come on and all activity stops - this is not good.. no leaks at all, processors look fine - feeling the pad under the processors - dry ! I haven’t really used the G5 very much, so I am not sure if this is a pump issue, or what.. I will try again to type yes in terminal to get it to do heavy load under Leopsrd.

 

[Krizzo]

The G5 Quads usually don't leak. There's probably air in the LCS after all those years. Every G5 Quad LCS should get an overhaul, they are more than 15 years old. No LCS holds up for that long. Also the cooling block for the second CPU is probably clogged. There's no way getting around a LCS overhaul or an air cooler swap.

 

[Byrd]

They leak, they always have. It usually happens very slowly around the CPU dies usually resulting in a crust around the site before eventually dropping onto the top plate of the PSU.

A future project is to immerse the water cooling loops into an ultrasonic cleaner from two Quad G5s. Both have had coolant and tubing replaced but there is a clearly a build up or crusty crud in the loop that a vinegar flush can’t resolve. The pumps in both are warm/overworked and the coolant doesn’t flow smoothly in the loop.

 

[Krizzo]

This is not true for the G5 dual-pump Quad. As opposed to the 2.5 and 2.7 G5s they have another CPU heatsink which doesn't have an O-ring since it's a solid copper block.

 

[Krizzo]

As for the flush, I have the same experience. I flushed my Quad three times now and I still have white gunk in the loop after a few days. It also seems to gas out, every time I disassemble the loop it is under high pressure and explodes in my face. I doubt that this is algae or similar, because I use biocide and distilled water of course. Very weird.

The CPU cooling blocks are made of copper and the rigid tubes and radiator are made of aluminium. This is not an ideal solition because the metals react with each other when wet. But I don't think that this corrosion process gunks up the loop that fast.

 

[beachycove]

I have a spur with an air vent (a hose end with a plug shoved in — I used a piece of fibreglass rod) installed on one of the lines of my Quad (single pump) at the highest point to allow air to escape on a flush/refill. The spur is otherwise plugged, obviously, for normal operation. The idea was to get trapped air out after refilling. The whole system gets frothy initially, and the contents would be under pressure consistent with an ‘explosion’ without that exit point. After running for an hour or so with the vent open, however, all is well, and it gets sealed.

Is at least a section of your tubing clear, so you can see what is going on?