MP 1,1-5,1 Mac Pro no signal anymore

[ZAK1813]

I was watching a YouTube video when all of a sudden the computer shut down. Then I turned it back on and everything seemed normal, but suddenly the image disappeared: a black screen. Since then I can't get an image. I thought it was the graphics card, so I got another identical one, but that didn't help.
I ran the tests.

OVTMP CPU A -> ok
OVTMP CPU B -> ok
No RAM diode problem...

When I press the diagnostic button, the 5V diode lights up when the computer is switched off. When I press it again and start the computer, the following LEDs light up:

PSU
5v
EFI DONE
GPU OK

But the SYS.PG LED doesn't!

Do you have any idea what's wrong? Could it be the power supply?

I plug my iPhone in usb and it’s not charging , keyboard no light. I heard the hdd start and all the fans are ok.

Sincerely

Mac Pro 5.1 - 2* 2,66ghz - gtx 680 2gb mac Edition and asus flashed gtx 680 (I bought from eBay this week)

 

[ZombiePhysicist]

Weird. Bad capacitor blown somewhere? Maybe on the code card?

 

[jmp473]

I've had similar symptoms that seemed to be caused by my 30" cinema display's power brick going bad. Usb problems stopped when I disconnected the display as a hub. I've also suspected my backplane. If you haven't yet - maybe try these tests: https://www.ifixit.com/Answers/View/559862/Mac+Pro+Won't+turn+on

 

[ZAK1813]

I've had similar symptoms that seemed to be caused by my 30" cinema display's power brick going bad. Usb problems stopped when I disconnected the display as a hub. I've also suspected my backplane. If you haven't yet - maybe try these tests: https://www.ifixit.com/Answers/View/559862/Mac+Pro+Won't+turn+on

My AOC display is working, I test it with my PS4.

The Mac Pro boot , no problem but the keyboard has no life, iPhone don’t charge.

@zombie : There’s no funny smell and I don’t see anything suspect.

I don’t understand why in the service manual they don’t speak about SYS PG led ?
What is it? (System Power General??)
It will be cool to have the list of all leds diagnostic.

I’m lost. It can be the power supply if usb doesn’t work?

Thank you for your support.

 

[ZAK1813]

Update : I bought a new PSU and … nothing has changed ! Do you think it’s the motherboard ? The SYS POWER GOOD is off always with the new PSU so what it can be ?

Sum up : new graphic card, new PSU, new battery.

 

[tsialex]

Update : I bought a new PSU and … nothing has changed ! Do you think it’s the motherboard ? The SYS POWER GOOD is off always with the new PSU so what it can be ?

Sum up : new graphic card, new PSU, new battery.

Now I'd test the CPU tray with another working Mac Pro to eliminate any possible problems. After that, I'd test a backplane.

Also, remove/disconnect any SATA devices, including the DVD. Defective SATA devices can make the Mac Pro to not work, several people lost days to finally find a defective SSD/HDD that when removed the Mac Pro worked fine.

 

[ZAK1813]

thanks for your support , I will buy a cheap 5.1 to test further. Do you think it can be the dust on the motherboard?

 

[tsialex]

thanks for your support , I will buy a cheap 5.1 to test further. Do you think it can be the dust on the motherboard?

I've had CPU trays that stopped working because the dust and the oily residue from the thermal pads degradation become conductive, other people like @Valdaquendë also had the same issue and a through clean-up got the CPU tray working again.

Backplanes doesn't have thermal pads, so, it's more difficult to have issues with just dust, but I don't doubt it that dust + humidity can make havoc.

Anyway, you should at least clean it with compressed air and apply contact cleaner spray everywhere there is a connector/slot/etc.

 

[BlueMacawBird]

You say the USB connections in the machine do not work; did you test all of them? Do you have an accessory USB card in the machine, and if you do does it work?

Have you gone through the process of removing everything from the machine to see if it will run with a minimum configuration, then adding things back one at a time?

And finally, is the machine a native 5,1 or a flashed 4,1? If you start swapping parts that may matter.

A couple of days ago I looked at what CMP 5,1 machines were selling for on eBay. Prices are very down for baseline systems, and even DP systems can be had for rather low prices if you shop carefully. There comes a point where you have done what you can to figure out why your machine is sick and you throw in the towel and get another one.

 

[ZAK1813]

I use usb keyboard : no lights, my iPhone : don’t charge.
I run the macpro with minimum but I don’t remove the dual cpu.
It’s a native 5.1. The SYS power good is off . In the 2008 manual , they say : ‘ All power rails are functioning’ if the led is on so it can only be the backplane ?

 

[BlueMacawBird]

I use usb keyboard : no lights, my iPhone : don’t charge.
I run the macpro with minimum but I don’t remove the dual cpu.
It’s a native 5.1. The SYS power good is off . In the 2008 manual , they say : ‘ All power rails are functioning’ if the led is on so it can only be the backplane ?

You reference a 2008 manual; the manual for a 5,1 (2010) is dated 2010/12/06. I expect the 2008 manual is for a MP 3,1 machine which is totally different from a 5,1

Search for the proper manual here on MacRumors:

pdf-apple-mac-pro-mid-2010-mid-2012-technician-guide-service-manual.2188557

Scroll through the responses and you will find the document, at least a link to download it.

 

[ZAK1813]

I use the 2008 manual only for the led diagnostic ; in the 2009/2010 they forgot the SYS PG led .

 

[ZAK1813]

Hi all ! News : I change the logic board and …………same problem of course ! Boot no chime black screen and SYS PG. is off .

I changed PSU, Graphic card, Logic board.

It can be the USB front panel with a short circuit? (But the power switch works) The CPU board ? (No errors).

Thanks friends!