# G5 won't boot



## alanw15 (Dec 8, 2009)

I have just replaced the PSU on my g5 dual 2.5 power mac

When i turn the machine on i get the white power light which goes off when releasing it the fans kick in and i hear the hard drive starting up.

After about 45 seconds of it being on the fans get louder and louder

There are no LED lights showing on the front and no screen at all and no chimes or flashing green lights.

I have reset the PMU Switch as well as the on board battery

Does this mean the logic board is dead?

Any suggestions would be great.


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## digitalPimple (Dec 8, 2009)

I have the exact same issue with a dual 1.8 and checked everything. I replaced the ram with working ram, replaced the video card with a working one and checked everything.
I tested the battery and it is fully working and has a full charge.

I have no idea where to go from here. This system was working 1 week ago and now nothing.

The ram, battery, Power supply and video card are working in another G5 (dual 2.0).

My keyboard and mouse do not respond so I can not enter any keys.


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## djackmac (Dec 8, 2009)

You'll need to try to reseat the processors. If that doesn't work some of the G5s would run on one processor. So if reseating them doesn't work try one processor at a time in the top spot to possibly rule out a bad processor.


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## alanw15 (Dec 8, 2009)

cheers for the help i booted from the cd and done a reinstall and all working at last 

thanks agian


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## digitalPimple (Dec 8, 2009)

I seated the processors and still no luck. I think my version will not boot like that. When removing either processor the system will not start.

How did you boot to DVD?

I have a MAC compatible keyboard not an OEM. Is that a problem? It's not on the other system.


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## alanw15 (Dec 8, 2009)

i pressed and held the 'c' button while booting up but this is on the OEM keyboard.


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## digitalPimple (Dec 8, 2009)

I have a mac pro plasitic clear keyboard. I have tried everything and still nothing. Seems the G5 iss not accepting any key strokes on mine.

It's almost like the open firmware is corrupt.

Anyone have any suggestions?


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## icemanjc (Dec 8, 2009)

digitalPimple said:


> I have a mac pro plasitic clear keyboard. I have tried everything and still nothing. Seems the G5 iss not accepting any key strokes on mine.
> 
> It's almost like the open firmware is corrupt.
> 
> Anyone have any suggestions?



The keyboard should not make a difference.
What exactly does yours do when you press the power button?


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## digitalPimple (Dec 8, 2009)

I have another with the exact same issue now. Great. Dual 2.7 water cooled:

1) When I press the button, the front LED lights up but goes off after release.
2) Fans start up, water pump goes, hard drive spins, dvd drive spins (if there's a disk). NO chime no beeps.
3) There is a red LED light near the lower processor. I noticed it looking through the front grill.
3) Monitor flashes "no connection" then goes black.
4) Unit sits for a few minutes then the fans gradually ramp up. Just sits like this.

That's it.
All key strokes do nothing. Mouse does not have the laser.

I held in the power button nothing. 
When I press the PRAM(?) button on the mobo the front panel LED lights up until I release it. Still nothing.

I tried installing my Leopard DVD but, it's a dual Layer I think, and it seems the super drive must have been swapped on this system at some point. It just ejects it back out.

I tried using a Dual Layer drive that works in my dual 2.0 system, but THIS system will not power it.. strange. Will not eject of spin. 

So next is a hammer...

Any suggestions?


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## icemanjc (Dec 8, 2009)

Take off the clear plastic plate that is inside the case of the G5. There should be a red and yellow LED that turns on, but you don't have to worry about those.

There are multiple LEDs on the left side of the slots for RAM. Count from the top a tell me which LEDs are red.

Also check if either of your G5's have these serials numbers, as Apple will replace the power supply of one's that were faulty in G5's for free. I think it is possible that you might have a power supply failure since the light stays on if you hold the button down, but go's of when you release because I had the same problem in a G4 I had, which the power supply was at fault.


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## digitalPimple (Dec 8, 2009)

No leads are on next to the ram slots.

I put in a working Power supply in the dual 1.8 with the same issue and it remains the same.

I will check the serial number.


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## icemanjc (Dec 8, 2009)

Hmmm, I must be getting my G5 models mixed up as mine has LED's there and the schematics thing online has them there too. Guess I'll check up on something else.
Where exactly are they?


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## digitalPimple (Dec 9, 2009)

I have 2 system displaying the same symptoms.
One is a dual 1.8
One is a dual 2.7 water cooled.

The dual 2.7 does not show any LEDS. I thought the same at first but nothing is lit up.

This is so odd.

The strange thing is the dual 1.8 was working a week ago now nothing. I put the working power supply in that system and still the same symptoms. I may take a break from apple systems for a while if this continues.


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## icemanjc (Dec 9, 2009)

digitalPimple said:


> I have 2 system displaying the same symptoms.
> One is a dual 1.8
> One is a dual 2.7 water cooled.
> 
> ...



Well if the LED's don't show up at all, it generally means that eithe the Power Supply is dead or the motherboard is.

Try making sure the Power Supply is seated well and just connect the required cables to run the computer, meaning none the power cables for any of the drives.


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## digitalPimple (Dec 9, 2009)

Heres a good one. On the other working power supply, when you first plug it in you hear a click. Like a switch goes on in the supply. Relay I believe.

On the dual 2.7 supply I do not hear that switch go off or on. Does the 2.7 have a differant supply, or are they all mostly 600watt systems in the powermac G5's?

I am going to find out what the problem is. I am determined!


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## digitalPimple (Dec 9, 2009)

Ok.. I just stripped the dual 2.7 system. It looks like there was a small water leak at some point. Nothing major but the power supply is a 450watter unit with 2 12v rails. How cn this be when a dual 1.8 system with no water pump is a 600w with 3 12v rails?

Am I right in assuming this is not the original power supply?

thanks


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## digitalPimple (Dec 9, 2009)

Yup. It's suppose to be a 600watt:
http://support.apple.com/kb/SP46


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## djackmac (Dec 9, 2009)

digitalPimple said:


> Ok.. I just stripped the dual 2.7 system. It looks like there was a small water leak at some point.



Apple was paying to fix all the water cooled ones that sprung leaks. If that things leaking, I'd call Apple. Every one of them I had serviced they paid to have everything replaced that the liquid touched which was mostly everything but the optical, HD, RAM and fans.


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## icemanjc (Dec 9, 2009)

digitalPimple said:


> Yup. It's suppose to be a 600watt:
> http://support.apple.com/kb/SP46



That's one of the reasons why only powering the motherboard would work because that would divert all the power there and might make it work. That is definitely a huge problem if it is underpowered, nothing will happen at all. Try getting ahold of a 600 watt power supply from a friend and trying it out.


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## digitalPimple (Dec 12, 2009)

The dual 1.8 system boots with the 450 watt but it seems one of the CPU's died. That's unbelievable. It boots with one cpu in the top slot. It was working a week ago.

????


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## djackmac (Dec 12, 2009)

That's really not that uncommon to see dead processors in those things. It seems like most of the G5 dual processors hit a certain point and one of the processors will go. You should double and triple check reseating the processors to see if it makes a difference, even though it is doubtful.


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## icemanjc (Dec 12, 2009)

djackmac said:


> That's really not that uncommon to see dead processors in those things. It seems like most of the G5 dual processors hit a certain point and one of the processors will go. You should double and triple check reseating the processors to see if it makes a difference, even though it is doubtful.



I find that odd though, my Late 2005 G5 has run fine for 4 years with no problems, but now I see everyone else with all these problems.


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## digitalPimple (Dec 17, 2009)

I examined the CPU board of both the dual 2.7 and the one dead 1.8 cpu. On all three some of the SMD components where missing or have partially detached from the board.

I replaced them but the CPU still does not power up. It seems once these CPU's go, they overheat and "pop" some smd components near the front of the cpu board. That is VERY strange.

I have never seen such a thing before. This is somewhat a design flaw on Apples part.

BTW, it seems Apple is willing to look at the 2.7 since it is a coolent leak issue. Not sure what they will do, we will see.


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