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Post by Meersbrook on May 4, 2008 22:25:41 GMT
Hi Guys The title says it all really My G5 runs as steady as a rock and reasonably quiet too until I ask the cpu's to do a little hard work eg gaming, at which point it locks up. The only thing that I can find wrong is that the right hand processor seems to run about 15 degrees hotter then the other, and this seems to be linked to the lockups. Diagnostics report that there is a problem with the right hand pump. Do you think the liquid cooling system is failing, and if so, is there a way I can replace it with something better then the original? Any help & advice would be much appreciated All that time lurking & learning , but when I finally get around to contribute by posting something I put it into the wrong board If the Mods could please transfer this post to General Hardware or G5 specific I would be very grateful
Chris
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Post by Meersbrook on May 8, 2008 13:23:30 GMT
Thanks for the move I've been putting off solving this problem for a while now as I'm afraid of making the problem worse, never having worked on a water cooled system before. I think that the most obvious answer is simply to fit a new right hand pump if I could get hold of one for sensible money. Unfortunately at this stage I can't even see an obvious way of disassembling the cooling system to remove the defective part After reading all posts for the last 10 months ( Yes, I need to get a life ) I know there are a lot of water cooling experts on here, which is why I'm wondering if any of you have replaced the whole system (presumably keeping the original block) with something more efficient, which could perhaps cool the video card too? Any advice gratefully received. If it leads to getting my spanners out I'll post photo's of any remedial work I do so other frustrated big G5 owners can have a laugh at my plumbing ;D ;D ;D Chris
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Post by B B on May 8, 2008 13:33:17 GMT
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Post by Meersbrook on May 8, 2008 19:18:36 GMT
Hi bb Thanks for the link. I'm well impressed with the soldering, and presumably the differing pipe bores force coolant round by convection to aid or replace the pump. Unfortunately my O level French isn't up to translating the board and I could do with some pointers in how to disassemble the G5 without damaging it. That said, I think I could fabricate the pipework if this ended up as the simplest solution to the problem; so anyone out there with knowledge on how to strip the beast down? Thanks again bb
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Post by B B on May 8, 2008 19:42:28 GMT
No problemo, you are welcome Meersbroeck. There must be around the net some description in English. I remember one from a German user but it was not a watercooled G5 . I can translate the part from French if you don't find in English. Edit : the link to Otto pages : g5.bhmm.net/
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Post by Meersbrook on May 9, 2008 11:20:01 GMT
I followed the link to Otto's site and then onwards to MIKX, both are useful in clearly showing the process up to & including getting the CPU shield off. I'm hoping that the water cooling assembly comes away as easily as the air cooled variety I really identified with the early comments in MIKX's article where he has to overcome his fear of tampering in areas the Apple has placed off limits. If my G5 was a PC I'd have stripped it down, tuned it up and rebuilt it months ago ;D ;D ;D I'll see how far I get over the weekend, and may need to take you up on the offer of translation if I get stuck. Thanks again bb. Chris
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Post by B B on May 9, 2008 13:37:39 GMT
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Post by Meersbrook on May 9, 2008 21:46:48 GMT
Brilliant! Thanks to bb's posts I've now got loads of info regarding how to get beyond the water cooling cover, so spanners in hand I start taking the beast apart. Only to fall back in amazement when I see that there is only one pump; by this time the French website photo's have finally downloaded and I see that his G5 only has one pump too If the beast's only got one pump why did the Apple diagnostics refer to the right pump? but something tells me that I should just ignore this and put it down to another example of "Apple's lovable quirkyness". A quick look at all the semi hidden allen bolts then tells me that the quirkyness extends to the need to buy a 15cm long allen key; another Saturday morning in Halfords then
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Post by nikonnut on May 11, 2008 2:31:38 GMT
Meersbrook, I've been browsing the links you posted and noticed that a few of the fasteners involved on the water cooling system seem to be of the Torx variety. Just a heads up Nik
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Post by Meersbrook on May 17, 2008 3:46:08 GMT
Hi Nik, sorry for the delay in answering but work got in the way of me having a good time again so I've just got back on line. You're right, there seems to be an unnecessary jumble of different fixings when you get the cooling assembly (with its attached processors) off the motherboard; mainly Torx then Allen lastly eight little Phillips just to keep you on your toes Although the system appeared complicated at first glance I managed to strip it down reasonably easily after I got over my Apple inspired anxiety, and both processor assemblies are now detached from the cooling system. The first thing I noticed (to my great relief is that theres no sign of leaking other then a tiny amount of crystal formations around both block joints. This needs attention, possibly strip, create silicon mastic seal and reassemble? The problem here though will be refilling the system as I've got no idea how to use the filling plug/vent on the rad and assume that it needs a special Apple tool The good news is that the pump and pipes seem rock solid and there's no evidence of past leaks anywhere in the machine. The second thing that leaped out at me was that the original builder had been a bit mean with the conductive paste when mating the processors with the blocks/heatsink plates. I know you aren't supposed to use gallons of it, but on one of the processors there was no evidence of contact over 50% of available surface This could explain why the failsafe systems were so eager to shut the G5 down if they were getting massively higher readings from that processor. You see where I'm going here -------- At best I'm a competent bodger, not a qualified IT Guy, but if I reseal and refill the cooling system, then use some highly expensive silver paste (my brother spent £20 quid on it but I know when he's out ;D) on the processors It might, just might solve the problem. If anyone knows how to bleed, refill and re-bleed the cooling system I'd be very grateful for any advice you could give. Many thanks for the help so far. Chris (currently surrounded by strange looking big lumpy bits of G5 and a load of odd machine screws)
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Post by nikonnut on May 17, 2008 4:19:08 GMT
Meersbrook, No worries Your comment about the fill valve (I assume that's the thing with the black cap on it?) made me re-visit the links you supplied and to me it sure looks like an automotive air-conditioning fill valve. Any idea what's under the cap? I'm guessing that there is something like a schrader valve (same type that is used to fill car tires) underneath. If that is the case I think it might not be too bad to re-fill but it will probably be a slow process Let us know what you find. edit: OK so I looked at this link www.neoview.com/g5/index.htm#6 and now I'm almost sure that it's a Low Pressure side A/C valve. That said I'm guessing Apple has some special tool to drain/fill/bleed the system Ugh. Oddly, Delphi used to be AC delco which was a division of General Motors. Kinda explains the automotive hardware.
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Post by B B on May 17, 2008 18:31:42 GMT
At the time I start the thread about Eaglefour , I has been busy to copy paste all the text with the idea to translate, but it was taking a lot of time because of the upload. Here are the first part interessing Meersbroek : Page 4 figure 5 : Ici le stator. La pompe est comme celle utilisée en aquariophilie. L’entraînement est assuré par une liaison magnétique. Cela évite qu’un arbre traverse les flasques avec à la clef d’éventuels problèmes d’étanchéité. Un gros joint torique assure l’étanchéité avec le couvercle de la pompe qui est la volute, car la pompe est de type centrifuge. Here is the stator . The pomp is the same that is used by aquasystem amateurs (aquariophilie in French) as within an aquarium. It works with a magnetic connection, to avoid some isolation problem if the arms of the rotor comes in contact with residual water. A large O ring is used to seal the cover which works as the top of the centrifugal pomp.That's not easy!! So technical .Page 4 figure 6 : The paddles of the RotorPage 4 figure 7 : Here is the Rotor. The bottom half circle is magnetic. The elecronic part inside the pomp creates the magnetic field which makes the rotor turn.Page 4 figure 8 : Rotor top view Thanks nikonut, you same me a lot of time, I found a pdf of the pomp as referred Delphi PPS GF 40 on the Lain.de site : www.laing.de/file/8When you read this you realize how complete and precise is Eagle4's report, he dissambled and pictured the pomp as shown in the pdf . No need to futher translate about the pomp. ;D Eagle4 refers to a survey from Cooler Master which compare different pomps including the Laing DDC Pomp, same as Delphi PPS GF 40, used by Apple and manufactured by Lain and Delphi in collaboration. Sorry it is in French too, but the pictures speak for themselves : www.cooling-masters.com/articles-22-2.htmlI will continue the translation with the cleaning, bleeding and refilling the system.
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Post by Meersbrook on May 18, 2008 9:42:49 GMT
Hi Nik Your comments are spot on accurate. I've just looked at the A/C equipment on a Vauxhall/Opel Astra conveniently parked nearby, and sure enough there are bits that look interchangeable with the G5. I also looked under the black dustcap on the G5 rad to find an exterior clamping ring (similar to a high pressure airline) and an inner threaded pipe with a black plastic ball at the bottom. The ball is pre tensioned and on gentle pushing coolent flows out. At this point I realise that "a picture tells a thousand words" especially as I lack an engineering background & vocabulary. I'm now going to consult the FAQ re. posting pictures Thanks again Nik
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Post by Meersbrook on May 18, 2008 10:13:45 GMT
Hi bb
Thanks for all the info. translations and leads. As there are no signs of leaking from the pump seal I think that I need to work out a way of testing mine off the G5 to ensure its efficiency, then flush & refill the system with new fluid. If it's inefficient I now know, thanks to you, that I might be able to get one from an aquarium stockist as Delphi are defunct ;D ;D
Prior to refilling I'd also like to remove the stainless heat exchanger plates (that sit on the processors) in order to check there are no bits of swarf or seal fragments under them partially blocking the coolant flow in these crucial areas. Obviously I would prefer to buy new seals for these plates but may need to fabricate them with silicon mastic as others have done. Incidentally these are the plates that have tiny crystal deposits around them showing the only area of leakage I've yet found. Does Eaglefour have anything to say on draining & refilling the system?
I hope to be able to repay your your help (and Nikonnuts) by posting some pictures of work in progress as an aid to other board members, so watch this space ;D
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Post by B B on May 18, 2008 12:24:31 GMT
At the Cooler Master link, they are showing the pump in test on page 7 . Eagle4 said not to connect directly onto the water distribution because the city pression will damage the pump. He used the Eheim valve for aquarium to refill the system . Eagle4 used a metallic bross mounted on a driller to clean framents on the stainless plates. I edit the last line of my previous posting as : I will continue the translation page 4 with the cleaning, bleeding and refilling the system. I am busy today with some cosmetic works on my Hack the Tosh and will do some work for you later in the afternoon. Well I can already say that Eagle4 cleaned with water and vinegar the pomp and rad and refill in with demineralized water mixed with 1% of a product used against corrosion and calcification for central heating called Sentinel X100 in France. www.sentinel-solutions.net/fr/chauff*ge/
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