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G5 Dual 2.5GHz - G5 is dead

Zotaccian

Zotaccian

macrumors 6502a
Original poster
Apr 25, 2012
645
7
So, I didn't manage to get that Dual G5 2.0GHz machine I wrote about here before, owner's friend got it. However, I bought faulty Dual G5 2.5GHz machine for little under 40USD incuding shipping. I haven't gotten it yet but it is already on its way.

I did not check beforehand which type of cooling it has and I was bit disappointed when I discovered that it is water cooled :confused:

According to description: The machine powers on, chimes but shows no picture and fans rev up. It has original graphics card in place plus couple gigs of ram.

I am already assuming that LCS has leaked, is there any good instructions available for this? That water cooling system is totally new for me, I have never seen one myself, not in PC's or Macs so I have very little knowledge about those and what I could possibly do.
 
To begin with, you'll find the LCS G5's the biggest PITA you've ever owned. They are full of so many problems and I regret both of mine to this very day and should have stuck with a dual 2.0/2.3

But... There are a few things you can do. The button under the RAM bank at the bottom would usually get mine to boot, and which was super weird it would boot right up if I unplugged the SuperDrive IDE cable. Try other simple little things like tinkering with the ram and reseating the Graphics Card, just basic stuff to try before going all hands in!
 
Well I got the machine and the case has suffered damaged, other side of the leg is detached. The machine powers on but does not accept any ram that seller included which I find hard to believe. It obviously does not chime. It does however recognize whether or not sticks are in place, if not two led blinks and if they are, three.

Seller had packed RAM in a very odd manner (=bad) but could all of them really be faulty? Maybe it is the motherboard...

Too bad I have only one 512MB DDR400 stick which I previously own and I know works.


EDIT: Okay I got the chime, does the RAM have to be installed on outer slots or should it reallly matter if you just install sticks on matchin slots? I got the chime when installing sticks on outermost slots. The internal speaker might be damaged, it makes that kind of noise but still the chime is heard clearly.
 
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So, I haven't disassembled this yet because I noticed I need longer screwdrivers for the water cooling, I do have correct type but I cannot turn the screws.

I noticed that this is missing PRAM battery, can Power Mac G5 power on without it? With PC's, it just keeps settings in memory but does missing it prevent PowerMac G5 from booting?
 
OK.

At the moment I am suspecting solder failure on those two chips on the back, one or both. After I manage to remove the cooling unit I guess I can get answers to whether or not suspect leakage... Or should I see any signs of it now? The cooling unit looks OK, the part I can see.

The machine came with 2 x 1GB and 2 x 256MB sticks, with those 1GB sticks it has never chimed but instead given three blinks, with those 256MB I get chime most of the time and then three blinks. I annot be sure if the RAM is OK, they are correct type though (400MHz)
 
Zotaccian said:
OK.

At the moment I am suspecting solder failure on those two chips on the back, one or both. After I manage to remove the cooling unit I guess I can get answers to whether or not suspect leakage... Or should I see any signs of it now? The cooling unit looks OK, the part I can see.

The machine came with 2 x 1GB and 2 x 256MB sticks, with those 1GB sticks it has never chimed but instead given three blinks, with those 256MB I get chime most of the time and then three blinks. I annot be sure if the RAM is OK, they are correct type though (400MHz)
Click to expand...

when you get the G5 cover off, look for little bits of white around where the aluminum tubes meet the rubber tubes. It should be pretty noticeable!
 
Hmm, I don't know if there are bits of something (brownish) or not. This machine has been inspected before me so it might have been cleaned?

https://www.youtube.com/watch?v=33E4nA3YvT0

By the way, I originally held the phone vertical so when watching the video you might be confused about how those CPU's and their cooling are placed, when I encoded the video with Handbrake it changed the aligment.
 
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Can someone point me to good screwdriver to use when removing the cooling unit? As far as I know it has to be Torx T10 but I don't know how long it should be? I can order it from eBay for example.
 
Cooling system / CPU's are now off, can't see any signs of leak so either it has not leaked or it has been cleaned before me:

13374621.jpg





EDIT: Well, removed CPU's and there was indeed blueish thing, not very much but still. Also when I reseated CPU's the machine does not give chime and/or error codes... I tried to be careful but did I still broke something? It powers on and after a while fans run full blast, no led lit on the front.... I didn't however tighten any screws on the cooling system.

EDIT2: There seems to be red light glowing near CPU. I tried to tighten the screws but no use. All pins in motherboard and in CPUs look normal. However, when inspecting CPU's (removing them from the CPU card) I might have not screwed them even, it seems like the another CPU is bit higher. I will continue this later, but at the moment I feel like putting this for sale for parts :)


13374767.jpg




EDIT3: Swapped CPU's, red light is gone and I was able to reset SMC (or SMU? I never remember which one it was on PPC etc) and now I get the chime again... followed by three blinks of front led.
 
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Three power light blinks means RAM problem, or dead memory controller on the logic board :(
 
Yeah, I know that the error points to memory. Unfortunately I don't have any other DDR systems around, but tomorrow or day after that I will get memory sticks which should work according to previous owner but I can't verify it myself. I do have 2 x 1GB sticks and 2 x 256MB sticks, condition is unknown, with those 1GB sticks there has never been a chime, those 256MB have given it several times but not always.

The red light is back again and on the same CPU. Strange thing that I could power on several times and get chime and now suddenly not. Also the red light is now not instant, it takes some time and then it appears.

Because the chime was not there on every boot with this memory which did give me chime atleast most of the time I do suspect motherboard and I am prepared to try reflowing those chips. Because the machine does not show picture / boot it doesnt' really matter if I destroy the board totally....


EDIT: Reseated CPU's and now red led is gone again, I think the mounting points on the another CPU are not on the same height as on the other CPU so it is bit lower and maybe does not go into its socket properly everytime. If I would tighten the screws of the LCS that would probably fix that problem.
 
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Zotaccian said:
Yeah, I know that the error points to memory. Unfortunately I don't have any other DDR systems around, but tomorrow or day after that I will get memory sticks which should work according to previous owner but I can't verify it myself. I do have 2 x 1GB sticks and 2 x 256MB sticks, condition is unknown, with those 1GB sticks there has never been a chime, those 256MB have given it several times but not always.

The red light is back again and on the same CPU. Strange thing that I could power on several times and get chime and now suddenly not. Also the red light is now not instant, it takes some time and then it appears.

Because the chime was not there on every boot with this memory which did give me chime atleast most of the time I do suspect motherboard and I am prepared to try reflowing those chips. Because the machine does not show picture / boot it doesnt' really matter if I destroy the board totally....


EDIT: Reseated CPU's and now red led is gone again, I think the mounting points on the another CPU are not on the same height as on the other CPU so it is bit lower and maybe does not go into its socket properly everytime. If I would tighten the screws of the LCS that would probably fix that problem.
Click to expand...

One thing you should have done is to actually take the CPUs off the LCS. Under there you will see if there is whiterice or not.
 

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Yes I did:

13375562.jpg



I don't know if this has been cleaned before me.
EDIT: Hmm, maybe it has since even that screw has some amount that thing on it.
 
Started disassembling today, if the LCS has leaked, it atleast looks like power supply is fine. Also the metal cover which required bending looks OK.

13375898.jpg
 
One other thing to watch out for if you rebuild the LCS is the crap that builds up on the piping. I had to work on making my 2.3 (was a 2.7 with a LCS, now air cooled 2.3) work today and I saw the LCS and took these pics. Nasty crap!
 

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I dunno if I will ever work on the LCS.... I have zero knowledge of it.


But right now I have question, how am I supposed to remove those mounting things where LCS/CPUs are screwed into? The only way seems to be to break them off which feels stupid.


13375946.jpg
 
Use pliers and twist at the bit that looks like it's for a socket, and once it's loose use your fingers to unscrew them.

And be totally careful. I nicked a capacitor off on the one in the middle on the right, I had to hot glue it back into place.
 
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Okay, the board is out.

Yeah I somehow managed to tear one of those stands of when taking out the CPU/LCS...
 
Removed the heatsink from the back of the board. Now I think it is obvious that someone has tampered this machine before since especially one of those white pins holding that one chip on the upper half of the board looked bad.

But I think I'll still try because I have disassembled this much.

From what I understand this is the unholy chip which I think was even designed by Apple themselves. This chip apparently is the one which fails (or its solder fails) and kills most of these machines. When I owned Power Mac G5 Dual 2GHz in the past which worked somewhat, I monitored temps and one chip ran even hotter than CPU's, I dunno if it was this or that another one.

13375999.jpg




EDIT: I remember reading somewhere that the upper chip is made by AMD and now that I look it, it looks like their K6-II and K6-III processors (I didn't remove the heatsink).
 
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Zotaccian said:
Removed the heatsink from the back of the board. Now I think it is obvious that someone has tampered this machine before since especially one of those white pins holding that one chip on the upper half of the board looked bad.

But I think I'll still try because I have disassembled this much.

From what I understand this is the unholy chip which I think was even designed by Apple themselves. This chip apparently is the one which fails (or its solder fails) and kills most of these machines. When I owned Power Mac G5 Dual 2GHz in the past which worked somewhat, I monitored temps and one chip ran even hotter than CPU's, I dunno if it was this or that another one.

Image



EDIT: I remember reading somewhere that the upper chip is made by AMD and now that I look it, it looks like their K6-II and K6-III processors (I didn't remove the heatsink).
Click to expand...

Going to oven it? I did mine for 7 minutes at 300*F with 4 coffee mugs under it. Put a foil ball on top of the chip so it has some weight to push it down. Works great still to this day. But I am still SOL on ram, max for me is 4GB. If I put in anything more it freezes up.
 

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No I'm thinking heatgun method, I have infrared thermometer and I will probably put piece of solder to the center of the chip and use it as additional indicator of temperatures.
 
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