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MP 1,1-5,1 Help! - Mac Pro 3,1 (2008), Won’t boot

P

PerkeoRoger

macrumors newbie
Original poster
Aug 28, 2024
9
0
Hi

Can anybody help me troubleshooting my 3,1 Mac Pro (2008)?

I recently got my hands on a Mac Pro 3,1 that is not booting. When I press the power button the white led stays steady, no chime and the fans start.

I don’t know almost anything about this computer, other than the fact that this unit may have been diagnosed with a bad power supply, but it’s not guaranteed.

I haven’t been able to discover which CPU’s it has but it had two graphics cards inside, one nvidea GeForce 750 (2gb), and one nvidea 8800gt. I think it may also be important to mention it didn’t came with any disk, (hdd or ssd), and that all of the ram slots are full.

I have been reading the manual and trying to diagnose it using the led’s on the board,

- when the button is NOT pressed:
SLP - off
STBY - off
ERRB - red
ERRA - off
OT B - off
OT A - off
GPU - off
PWRG - off
EFI - off

- when the button is pressed:
SLP - off
STBY - yellow
ERRB - red
ERRA - off
OT B - off
OT A - off
GPU - green
PWRG - green
EFI - off

- I have also pressed the reset switch but nothing happens.

The computer does not show any video in any of the graphics cards.
I have verified the voltage of the motherboard and everything seems good (3.00 V)

I have tried to see if it would show anything when a disk with El Capitan taken from a working MacBook 2009.

I you happen to know something about this please give me a hint!

Thank you very much for your time!
 
Mac Pro even beeps?

Did you confirmed that the GPUs are working?

Did you tried to clean the memory risers? Tested one riser at a time? Any memory riser LEDs lit?
 
tsialex said:
Mac Pro even beeps?

Did you confirmed that the GPUs are working?

Did you tried to clean the memory risers? Tested one riser at a time? Any memory riser LEDs lithos
Click to expand...
Hi,

No the Mac Pro does not make any sound or chime.
The only thing the gpus do right now is spinning the fans.

I have 8 sticks of ram with dissipador, I have gone through the service manual and tried all of the combinations presented there.

I have tried cleaning the risers, but nothing.

The only light on inside of the computer is the ERRB on red and I have noticed a new flashing light on OT A. The risers only flash four red light when I turn the computer on.

I think that the attached scenario present on the service manual is the one I am facing..
 

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Did you verified the RTC battery voltage? A non-working RTC makes the Mac Pro fail at POST. Do you have any AppleOEM GPUs? You only have pre-boot configuration support with an AppleOEM (8800GT?) unless the GT750 is flashed.

You can boot an early-2008 with just one Xeon present, installed to processor socket B, the lower one. Test both processors one at a time with socket B:

MacPro 3.1 early 2008 Quad core 2.8. upgr… - Apple Community

discussions.apple.com discussions.apple.com

With the ERRB LED lit, seems to me a dead logic board, but before starting looking one to buy I would do the elimination game.

If you have access to another working early-2008 Mac Pro test the PSU with the working early-2008, just to eliminate it, since PSUs are tricky to test without load and correct signals.
 
Yes I did verified the voltage on the battery and it was 3V.

I don’t have access to another Mac Pro to try that, but I can try swapping the processors and see if the light follows.

Would you say that is a good idea?

By the way are you suggesting me to try the GPUs for example on a windows machine?
 
PerkeoRoger said:
Yes I did verified the voltage on the battery and it was 3V.

I don’t have access to another Mac Pro to try that, but I can try swapping the processors and see if the light follows.

Would you say that is a good idea?
Click to expand...

Yes.

PerkeoRoger said:
By the way are you suggesting me to try the GPUs for example on a windows machine?
Click to expand...

For the 8800GT you'll probably need an old BIOS PC, this GPU will not work with a modern UEFI class 4 PC (usually anything past Intel 8th gen does not have CSM/legacy support anymore), but the GT750 will probably work.

The 8800GT is AppleOEM?
 
tsialex said:
Yes.



For the 8800GT you'll probably need an old BIOS PC, this GPU will not work with a modern UEFI class 4 PC (usually anything past Intel 8th gen does not have CSM/legacy support anymore), but the GT750 will probably work.

The 8800GT is AppleOEM?
Click to expand...
Hi,

I have exchanged the processors and after multiple experiments I ave been able to confirm the following:

- the ERRB light goes away when any of the processors is installed on socket A, with the other socket empty

-when both processors are installed in socket a and b, the result will always be the same, the ERRB light turns on

- when any of the processors is installed in socket b, both with the other empty or full, the light will turn on


There’s still no chime.

Any thought on this?
 
Socket B is the main one with an early-2008, if you are getting ERRB LED lit whenever you install a processor to it, unfortunately the most probable is that you have a defective logic board.
 
tsialex said:
Socket B is the main one with an early-2008, if you are getting ERRB LED lit whenever you install a processor to it, unfortunately the most probable is that you have a defective logic board.
Click to expand...
Does that mean that I would need to buy a logic board to get the Mac to boot?

I saw there were some Mac Pros 2008 with only one cpu,

Can’t I just use it for sometime without any cpu on the socket b?
 
tsialex said:
Yes.



Yes, socket-B installed CPU. I've sent you the link to the pictures of one.



Nope, you need to have a CPU installed to socket B for the Mac Pro to work.
Click to expand...
Would you say it is worth the price (100€) that I would need to pay, or should I just sell it for parts?
 
PerkeoRoger said:
Would you say it is worth the price (100€) that I would need to pay, or should I just sell it for parts?
Click to expand...

You have to make some calculations if is worth or not for you.

I'd look at an early-2009/mid-2010/mid-2012, if you have some patience and search everyday for a while you can get a barbebones working one for not much more money.

Classic Mac Pros by now demand some maintenance and a lot of people does not have the skills/time to do it and just sell it cheaply.
 
tsialex said:
You have to make some calculations if is worth or not for you.

I'd look at an early-2009/mid-2010/mid-2012, if you have some patience and search everyday for a while you can get a barbebones working one for not much more money.

Classic Mac Pros by now demand some maintenance and a lot of people does not have the skills/time to do it and just sell it cheaply.
Click to expand...
I understand and the only thing I can say is that I am passionate about the design of these Macs and the idea of an upgradable Mac tower.

I have been thinking and I figured I can’t be shure if the problem is indeed the logic board and wasting around 100€ on it doesn’t seem that safe.

My problem now is to decide if I let my desire of having one of these machine preferably a 5,1 working to control or if I invest in parts.

After searching around the prices on ebay for the 5,1 are always (Mac+shipping+vat) around 400€ to 500€ and that is certainly more than the amount I would be ready to pay for it.

This would never need to be my main machine as I have my trusty MacBook with Apple silicon. I will try to do what you say and continue searching!
 
I'd look on the local version of FB MarketPlace/Craigslist/etc instead of eBay. There are several reports here of people in the EU finding working examples on the cheap at e-recyclers.

Another thing that I'd look besides a MacPro4,1/5,1 is an early-2008 with a banged up case, two makes one and you can sell any unneeded working parts.
 
tsialex said:
I'd look on the local version of FB MarketPlace/Craigslist/etc instead of eBay. There are several reports here of people in the EU finding working examples on the cheap at e-recyclers.

Another thing that I'd look besides a MacPro4,1/5,1 is an early-2008 with a banged up case, two makes one and you can sell any unneeded working parts.
Click to expand...
That’s good advice thank you.

I will mention that prior to this Mac Pro 3,1 I had been searching on e recyclers for months.

I will continue my search!
 
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