Power-Mac G5 not booting?

comradecommie

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Original poster
Sep 30, 2017
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I just recently bought a G5 Power-mac for a dollar, and nothing works. It powers up, and then the fans continually ramp up. I have tries moving the RAM around according to the (online) manual, and its all identical so I just left it the way it was, just inverted. The graphics card is the 6800 Ultra AFAIK, the serial check websites are saying its 2 different Radeons, but it isn't. With the GPU out, the fans don't go jetspeed ahead, but there still isnt a chime. The PSU makes a tiny shock noise, barely audible, when I plug or unplug it.
 

d-oost

macrumors 6502a
Jan 10, 2016
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What model/specification PowerMac G5 is it? That might help narrow down problems a bit.
 

AphoticD

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Feb 17, 2017
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Is the hard drive spinning up and making any activity noises with/without the GPU?

Try connecting a Firewire cable from the G5 to another Mac, then hold down the T key while you power it on to put it into Target Disk Mode. If the HDD mounts on another Mac then you have confirmed that it’s not a power supply issue and the Mac is likely passing it’s POST check for RAM and CPU.

If you get nothing from TDM, you could try reseating the CPUs. This is a bit of a pain to do on a G5, but once you’ve got the right tools, it can be done fairly quickly.

I had a similar experience with a Dual 1.8ghz G5. It would only boot WITHOUT a graphics card. It didn’t matter which card I tried, but if an AGP GPU was installed, it would just run the fans and not get anywhere. To also add to the confusion, the front panel on this G5 believed there was something plugged into the headphone jack so the internal speaker was disabled and I never heard a boot chime or error beep.

If yours has similar issues, try this; grab a set of headphones/earphones or speakers and plug it into the front. Try booting again with/without the GPU and listen for a boot chime or error beeps from your headphones.

If you are getting a happy sounding boot chime without the GPU, try replacing it with a cheap option like the AGP Nvidia FX 5200 or an ATI 9600, (or any Mac PCI card like the Radeon 7000 or 9200) just to get it up and going.

If your G5 shares the same fate as mine did and refuses to boot with an AGP GPU, then the AGP slot has failed completely and a logic board replacement is likely required (or a bake in the oven to reflow if you don’t mind the toxicity).

At this point you may consider using the giant aluminum tower to build a Hackintosh or even turn it into office furniture.
 

comradecommie

macrumors newbie
Original poster
Sep 30, 2017
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@z970mp
No.
@AphoticD
It makes spinning with or w/o GPU, but the problem is I don't have another mac, nor do I have a firewire cable. I don't have any idea how to even take the CPU cover off, let alone reseat them. I currently cannot order anything, though if it is the only option I'll scrounge up a few dollars. Any idea if you can resolder the AGP slot if it is the failing part of the MOBO?
Also, a Hackintosh isn't too out of my league if I can get a cheap deal on a 3rd gen Intel CPU for a MOBO i got for free a while back...
 

AphoticD

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Feb 17, 2017
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@z970mp
No.
@AphoticD
It makes spinning with or w/o GPU, but the problem is I don't have another mac, nor do I have a firewire cable. I don't have any idea how to even take the CPU cover off, let alone reseat them. I currently cannot order anything, though if it is the only option I'll scrounge up a few dollars. Any idea if you can resolder the AGP slot if it is the failing part of the MOBO?
Also, a Hackintosh isn't too out of my league if I can get a cheap deal on a 3rd gen Intel CPU for a MOBO i got for free a while back...
Did the headphones give you any boot chime?

Take a look at the repair guides at https://www.ifixit.com/Device/Power_Mac_G5
https://www.ifixit.com/Device/Power_Mac_G5
Also, download the Apple Service Manual for your G5 at http://tim.id.au/laptops/apple/powermac/
(I believe the dual 2.7 will be covered in the powermac_g5.pdf, not the late 2004/2005 manuals)

While you've got it apart, it would be worth checking the liquid cooling for any signs of leaks, corrosion, etc

In theory, yes, you possibly could resolder the AGP if you are confident in doing so. I decided not to mess with my logic board though and initially planned to run it as a headless server due to the fault (or install an underpowered PCI based GPU in it if it were cheap enough).

Eventually, I found a decent price on a replacement logic board to bring the old tower back up to full working order (shipped USA->Australia last year).
 

AphoticD

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Can I use USB headphones/speakers? I don't have any 3.5mm ones laying around.
Probably not. This is analog audio out from Open Firmware we’re working with. USB (digital) audio drivers load up later on as part of the OS.

Maybe you can borrow a set of headphones with a 3.5mm plug? They tend to multiply on their own in my house.
 
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comradecommie

macrumors newbie
Original poster
Sep 30, 2017
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Another thing - people are saying swapping processors around may help, but the pin to take off the heatsink cover is pushed in so I can't get to it.
EDIT: Found a monitor with a speaker, plugged in, still no chime.
 
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weckart

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Nov 7, 2004
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Don’t these things have an LED bank on the logicboard, which indicate what the fault is? Assuming that power is getting through, one or more of these should be lighting up.
 

d-oost

macrumors 6502a
Jan 10, 2016
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Given these systems do have liquid cooling, it's not completely unlikely it has begun to leak and is causing issues, although it doesn't have to. But I would wholeheartedly recommend you pick up the tools to remove the CPUs from the machine for inspection.
 
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AphoticD

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Don’t these things have an LED bank on the logicboard, which indicate what the fault is? Assuming that power is getting through, one or more of these should be lighting up.
The 11,2 Dual and Quad Core machines definitely have the self-diagnosis LEDs.

But I'm not sure if the Dual 2.7GHz had this feature. I could be wrong, but my understanding is the 2.7 was based on the original G5 logic board design. The only LED you'll see light up is for when the perspex deflector door is open (or if the air deflector sensor board has failed).
[doublepost=1506863624][/doublepost]Just reading through the powermac_g5.pdf Service Manual...

Step through the section titled:
Startup Failures for Power Mac G5 (June 2004 Dual 2.5 GHz/ Early 2005 Dual 2.7 GHz)
(Page 188)

One thing that hasn't been mentioned on the thread yet is to try Resetting the PMU on the Logic Board (Page 176) This may do the trick, but the processor reseat will more than likely be required.

I don't have any experience with the LCS units, but from what I understand, most cases of failure on these early Liquid Cooled G5s was gasket/o'ring fatigue causing leaks of the highly corrosive coolant, which ultimately damages other sensitive components.

Are there any visual signs of coolant leakage or corrosion?
 

comradecommie

macrumors newbie
Original poster
Sep 30, 2017
13
4

The 11,2 Dual and Quad Core machines definitely have the self-diagnosis LEDs.

But I'm not sure if the Dual 2.7GHz had this feature. I could be wrong, but my understanding is the 2.7 was based on the original G5 logic board design. The only LED you'll see light up is for when the perspex deflector door is open (or if the air deflector sensor board has failed).
[doublepost=1506863624][/doublepost]Just reading through the powermac_g5.pdf Service Manual...

Step through the section titled:
Startup Failures for Power Mac G5 (June 2004 Dual 2.5 GHz/ Early 2005 Dual 2.7 GHz)
(Page 188)

One thing that hasn't been mentioned on the thread yet is to try Resetting the PMU on the Logic Board (Page 176) This may do the trick, but the processor reseat will more than likely be required.

I don't have any experience with the LCS units, but from what I understand, most cases of failure on these early Liquid Cooled G5s was gasket/o'ring fatigue causing leaks of the highly corrosive coolant, which ultimately damages other sensitive components.

Are there any visual signs of coolant leakage or corrosion?
No LEDS in here, and no signs of corrosion, but I'm still stuck on getting the pin out because I accidentally got it pushed in, so it's going to take quite a while to even get into the main processors area. If the cooler come out bad, but I still manage to get all of the coolant and corrosion cleaned off, will I be able to stick on gasket rings from the hardware store?
Also I did reset the PMU yesterday, but apparently if it's pressed twice, it crashes is. Will I have to wait for it?
 

z970mp

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Jun 2, 2017
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

No LEDS in here, and no signs of corrosion, but I'm still stuck on getting the pin out because I accidentally got it pushed in, so it's going to take quite a while to even get into the main processors area. If the cooler come out bad, but I still manage to get all of the coolant and corrosion cleaned off, will I be able to stick on gasket rings from the hardware store?
Also I did reset the PMU yesterday, but apparently if it's pressed twice, it crashes is. Will I have to wait for it?
Try taking a screwdriver or something and get it positioned under the pin through the gap in between the processor cover and the thing on the right, then just start pushing upwards. That's what I did. After I had to put it back on, I just put a screw where the pin should be for ease of access next time.
 

d-oost

macrumors 6502a
Jan 10, 2016
709
830


No LEDS in here, and no signs of corrosion, but I'm still stuck on getting the pin out because I accidentally got it pushed in, so it's going to take quite a while to even get into the main processors area. If the cooler come out bad, but I still manage to get all of the coolant and corrosion cleaned off, will I be able to stick on gasket rings from the hardware store?
Also I did reset the PMU yesterday, but apparently if it's pressed twice, it crashes is. Will I have to wait for it?
It's not so much corrosion on the heatsink you need to worry about, as much as corrosion on the logic board and CPU boards. If it's not too bad, and none of the potential shorts caused by the corrosion have managed to break anything, cleaning it up and overhauling the LCS completely would solve your issues. But that's only if it hasn't done damage to the PCBs.
 
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comradecommie

macrumors newbie
Original poster
Sep 30, 2017
13
4
It's not so much corrosion on the heatsink you need to worry about, as much as corrosion on the logic board and CPU boards. If it's not too bad, and none of the potential shorts caused by the corrosion have managed to break anything, cleaning it up and overhauling the LCS completely would solve your issues. But that's only if it hasn't done damage to the PCBs.
I got the cover off after an hour of -bleep-ing with that plastic pin, and now I'm ready to take off the cooler and swap the processors, I'll report back after cleaning off corrosion, cooler liquid, and possibly changing the liquid. Fingers crossed!
EDIT: huge roadblock.
Check pics, tell me what to do, most of the mb and case right there is damp.


[doublepost=1506886194][/doublepost]Corrosion is really bad on the case, but what should I use to clean it? Also, do the processors look fine and HOW DO I EVEN SWAP THEM?
 
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comradecommie

macrumors newbie
Original poster
Sep 30, 2017
13
4
UPDATE: I got the processor off and cleaned corrosion, but does anyone know how to flush the water pump and put distilled water in it? I heard it wont rust so if the pc breaks atleast I wont have to dig through a barrier of corrosion.
 

comradecommie

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Original poster
Sep 30, 2017
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z970mp

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Uhh, quick thing - thing was corroded like hell and when i went to unscrew it so I could get some tubing from the auto store, some **** got in my eye. Do you know what was in the pump at factory?
Here are my findings.

One comment from this thread, https://www.ifixit.com/Answers/View/15451/What+is+the+Cooling+System+Liquid+made+of, said this.

"The best information I could find regarding the liquid, is that its green and may be propylene glycol. I found more reliable "looking" information that says its Delphi 151 Coolant Fluid."

Another guy said this.

"I did speak with Delphi support member (while they were undergoing reorg) and was told that the solution is just a refined version of high grade antifreeze. No water was used in the original manufacturing."

If you'd like an official answer of how to get it out, I took this from my Late 2005 PMG5 user manual.

"If coolant contacts eyes, rinse thoroughly with water."

But at the very least, you won't die, and you won't go blind. I hope I helped.
 
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comradecommie

macrumors newbie
Original poster
Sep 30, 2017
13
4
Here are my findings.

One comment from this thread, https://www.ifixit.com/Answers/View/15451/What+is+the+Cooling+System+Liquid+made+of, said this.

"The best information I could find regarding the liquid, is that its green and may be propylene glycol. I found more reliable "looking" information that says its Delphi 151 Coolant Fluid."

Another guy said this.

"I did speak with Delphi support member (while they were undergoing reorg) and was told that the solution is just a refined version of high grade antifreeze. No water was used in the original manufacturing."

If you'd like an official answer of how to get it out, I took this from my Late 2005 PMG5 user manual.

"If coolant contacts eyes, rinse thoroughly with water."

But at the very least, you won't die, and you won't go blind. I hope I helped.
Phew, thanks. Currently in progress of literally parting the cooler as much as it can to get it ready. Gonna buy some tubing soon, thinking 1 1/2 ft. should be good enough? Also, some of those brown thrings on the processor board were rotted off, and aren't there, should I be concerned? Also checking the power supply for corrosion tomorrow, as per @Daniël Oosterhuis word.
 
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z970mp

macrumors 68040
Jun 2, 2017
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Phew, thanks. Currently in progress of literally parting the cooler as much as it can to get it ready. Gonna buy some tubing soon, thinking 1 1/2 ft. should be good enough? Also, some of those brown thrings on the processor board were rotted off, and aren't there, should I be concerned? Also checking the power supply for corrosion tomorrow, as per @Daniël Oosterhuis word.
Anytime, pal.

Should you be concerned? Probably.

At this point, I would just salvage what you can, ditch it, and buy an air cooled model. One of the dual core revisions, specifically. Much less problems.
 

AphoticD

macrumors 68000
Feb 17, 2017
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Australia
Without a doubt, the seller knew all about this.. that's why it was a dollar!

You've got a bit of a big job to clean it all up. Take your time and pull EVERYTHING apart, especially the Power Supply Unit, open it up, carefully blow out all of the loose dust with a compressor (or canned air) and clean all the components with cotton tips and a couple of old toothbrushes. Be sure to leave the PSU unplugged for a couple of hours before opening it up though, you don't want a zap from any residual power.

Pull the main board out and clean in behind as well. It can take a few hours to get into the G5 on your first attempt. It's not like working on a PC (or a G4). You'll need the right tools. I went full McGyver on this and fashioned a long-handled hex-key from whatever I could find in my toolboxes (imagine a straightened out smaller L-shaped Hex-key, joined with cable-ties to another larger hex key for leverage). This is required to remove the CPUs and heatsinks on the air-cooled units. I'm not sure if you can use a shorter tool on the LCS.

For cleaning components, I've always used Isopropyl Alcohol (99%). I don't know about mixing this with the leaked coolant though, maybe someone with a chemistry background could chime in on this. You don't want to turn your logic board into soup.

On the corroded panels and screws, you could possibly rub the rust back a bit with some fine wet and dry sandpaper then use a water dispersing product to protect it from any further corrosive ingress (I'd use WD-40 here in Australia, not sure if it exists in other countries). If you wanted to go the extra mile, coat the areas in a rust converting paint, or just find replacement parts from another cheap (non-rusted) G5.
 
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