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G5 PowerMac problems

R

rjwbaker

macrumors newbie
Original poster
Jul 28, 2014
24
0
Oslo
Hi, i have been scouring the internet for the answer to the problems i am having with my 2ghz dual G5 Powerpc.

First, this is my mac
http://www.everymac.com/systems/apple/powermac_g5/specs/powermac_g5_2.0_dp.html


It started with what i thought was a power supply problem, symptoms were clicking noise when pressing the power button but system not starting up.

I bought one of these,
Apple PowerMac 614-0307 Power Supply 600W
The Ebay seller said it was compatible and installed it today, although i noticed that the part numbers of the old and the "new" do not match exactly.

Whats happening now is the machine powers up, but the powerled does not stay on, fans whirl up and there is no chime. The attached cinema display does not show a picture.

I have checked the ram by removing some of it and restarting the system.
Checked all the cables i removed to replace the psu today.
I have checked the pram battery by starting up another system with it.
I started up the computer without the video card, still no chime.
There are no red leds showing inside except for when the plastic wind channeler thing is removed.
I have also reset pram memory-didnt make any difference.

Could it be the Logic board? how could i test this?
Anyone have any suggestions to try?


your help would be greatly appreciated.

Thanks

rob
 
rjwbaker said:
Hi, i have been scouring the internet for the answer to the problems i am having with my 2ghz dual G5 Powerpc.

First, this is my mac
http://www.everymac.com/systems/apple/powermac_g5/specs/powermac_g5_2.0_dp.html


It started with what i thought was a power supply problem, symptoms were clicking noise when pressing the power button but system not starting up.

I bought one of these,
Apple PowerMac 614-0307 Power Supply 600W
The Ebay seller said it was compatible and installed it today, although i noticed that the part numbers of the old and the "new" do not match exactly.

Whats happening now is the machine powers up, but the powerled does not stay on, fans whirl up and there is no chime. The attached cinema display does not show a picture.

I have checked the ram by removing some of it and restarting the system.
Checked all the cables i removed to replace the psu today.
I have checked the pram battery by starting up another system with it.
I started up the computer without the video card, still no chime.
There are no red leds showing inside except for when the plastic wind channeler thing is removed.
I have also reset pram memory-didnt make any difference.

Could it be the Logic board? how could i test this?
Anyone have any suggestions to try?


your help would be greatly appreciated.

Thanks

rob
Click to expand...
Could be the new PSU.
 
Hmm, i was thinking that too, but would an incompatable psu start the computer but cause an error for it not to chime etc?


I am suspicous of the new psu with it not having the exact same product number as the one it replaced, it is listed though as fitting the A1047 model, and the seller (whom i assume is better schooled in this than me) said it would fit, plus the computer starts now, which it didnt do before.
 
rjwbaker said:
Hmm, i was thinking that too, but would an incompatable psu start the computer but cause an error for it not to chime etc?


I am suspicous of the new psu with it not having the exact same product number as the one it replaced, it is listed though as fitting the A1047 model, and the seller (whom i assume is better schooled in this than me) said it would fit, plus the computer starts now, which it didnt do before.
Click to expand...
I suppose if the amount of power on some cables not being the same causing parts not to fully start could cause the Mac not to see them and fail to chime.
 
very interesting, i should maybe buy another that matches the old one exactly.

This would be preferable than replacing a logic board, plus i have already spent around $50 on it, as much as i really really want to get it going again, there sadly is a limit to how much i can spend / that is sensable to spend on it.

Thanks for your input Altemose, i appreciate it.
 
Apple's service manual would be a really nice thing to have.
Google (or DuckDuckGo) is a good place to search for that.

Anyway - Power LED goes out, no boot chime, no video, but the fans run….
Try reseating the processor/heat sink assemblies. Some G5s will run with just one processor, and you could try removing just the bottom one, and see if it will get further into the boot. (However, IIRC, the dual-2.0 GHz can't boot with just one processor installed. Might make a nice test anyway) You COULD swap upper to lower, both reinstalled. The fans will run at full speed (and make a lot of noise), but it will allow you to boot and use your G5. You can run the Calibration utility to control the fans again, or just swap the processors again. The swap, and swap back will reseat the processors, which might be a good fix, too.
If you want to try the calibration utility, that's only available on Apple's Service Diagnostics (ASD) CD (not the Apple Hardware test, which is the consumer test). You will need ASD version 2.5.8 for your G5.
 
Before you spend any money try to check what voltages and amps are coming out of the replacement PSU and compare with the original one. If they match, then something is likely up with the logic board - a broken trace, loose socket, faulty ram slots.

Ifixit has a checklist but I think you have probably exhausted this already.

https://www.ifixit.com/Wiki/Apple_G5_Troubleshooting
 
Deltamac, for fun i tried swapping them around, mostly for to check i hadnt doen it by accident and still the computer didnt boot, the fans didnt behave differently either though to how they do with the processors installed correctly. I will try booting woth just one to see what happens.

Will post back what happens.

Cheers

----------

Weckart, can you describe how i check the voltage coming out of the psu? What value should i be getting?
 
If you want to try, remove the lower, as I am sure you won't get anything with just the lower installed.

RAM problems can sometimes cause strange boot problems.
Check what happens when ALL the ram is removed, then try booting. Obviously it won't boot, but you should get the "no memory is installed" error - which is simply a power LED that repeats with one flash. It shouldn't just go out after being on the first time, but repeats one blink.
Reinstall ONE pair of same size RAM in the center slot pair (that would be Slots 1 on both banks, or slots 4 and 5, if you want to count slots that way. Leave all other memory out. As long as you have 2 x 256 MB or larger, you should be fine to boot any system that your G5 can run.
AND, try booting with that pair only. Might help (might not :D )

The service manual has info about power supply voltage testing, where to test, and how to do that testing.
Another good reason I suggested finding the service manual.
 
Last edited:
Thanks Deltamac, i will look into that manual and test the voltage on the psu tomorrow.

Just now i took out all the ram and started the system, i didnt get a warning flash of the power led. The Led light comes on once when i press the button then goes out again immediately.

So no change.

Then i reinstalled the RAM and removed the bottom processor and started the computer again, the same things happened as as happened before, the power led goes out, the fans swhilr up then calm down, there is no chime and no signal to the monitor. If ti leave the computer on long enough then the fans increase in speed.
 
This is probably a waste of time but can you check the power connector sockets on the board? Or in fact any other socket wired up?

A bent pin here or there can go unnoticed but prevent booting up. I had a whale of a time trying to work out why my Powermac G4 would not even start but made funny noises out of the psu until I noticed a bent pin on the ACD port of my graphics card. It was causing a short and the system refused to chime or boot until I bent it back. It very was difficult to see and about the last thing I checked.
 
Thanks Weckart, i will check that also tomorrow, all the suggestions are much appreciated gentlemen thankyou.

I will keep you updated.
 
rjwbaker said:
very interesting, i should maybe buy another that matches the old one exactly.

This would be preferable than replacing a logic board, plus i have already spent around $50 on it, as much as i really really want to get it going again, there sadly is a limit to how much i can spend / that is sensable to spend on it.

Thanks for your input Altemose, i appreciate it.
Click to expand...
If the PSU turns out to be a dud I would look at the return policy.
 
I just checked the voltage coming from the PSU according to Apples procedures laid out in the manual (cheers DZ/015) and where the value should be +5v it is just over 3v.
 
rjwbaker said:
I just checked the voltage coming from the PSU according to Apples procedures laid out in the manual (cheers DZ/015) and where the value should be +5v it is just over 3v.
Click to expand...

Probably faulty capacitors inside the power supply caused by excessive heat over time. Open the power supply to confirm.
 
Hi Archtopshop,

thanks for the tips i will do that, however what would faulty capacitors look like?
Fried, burnt or discoloured i am guessing?

regards

Rob
 
The typical faulty capacitor has a rounded, puffy looking top. A good properly working capacitor has a completely flat top.
 
rjwbaker said:
Hi Archtopshop,

thanks for the tips i will do that, however what would faulty capacitors look like?
Fried, burnt or discoloured i am guessing?

regards

Rob
Click to expand...

Hi Rob,

What Intel said--they should have flat tops. They have vents (weak spots) on their tops, so when they fail the tops bulge at the weak spots, and may even open to let out the gases. This keeps them from blowing up like little fire crackers.

If you google "bad capacitors" and click on images, you can see thousands of examples. They were a big problem in the early/mid 2000's for all brands of computers, and still cause many problems in today's LCD TV's.
 
Thankyou Archtopshop, when i figure out how to break into it i will inspect it :) If there are some that are bulging or destroyed is the only option then to replace the entire psu?
 
rjwbaker said:
Thankyou Archtopshop, when i figure out how to break into it i will inspect it :) If there are some that are bulging or destroyed is the only option then to replace the entire psu?
Click to expand...

Failed capacitors can be replaced. You will need desoldering/soldering equipment and skills. If you don't already meet these two requirements, then it will be less expensive to just purchase a replacement power supply.

There are tutorials for replacing capacitors on badcaps.net., if you want to explore that route.

Good luck with your G5!
 
Thanks Intell for the advice, Archtopshop too. Today i opened up the power adapter and all looks fine, at least to my untrained eye. I have paid extra attention to the capacitors and noe seem to be swollen or damaged.

I will put it back together again and pop it in the computer, i am not expecting any change but who knows maybe its my lucky day.
 
I took the opportunity to replace one of the fans on the psu with another from the previous psu as the new one got damaged in the post, inspected it for damaged capacitors put it back together and threw everything else back into the machine :) but unfortunately and consistantly i am getting the same result. Fans whirl up, LED light doesnt not stay lit, no chime, sounds like hard disk is spinning up too but computer doesnt boot, fans will stay start to go faster and faster the longer i leave the computer on. The computer can be turned off either by holding the power button on hte machine or on the attached apple cinema screen.
 
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