MP 1,1-5,1 Mac Pro 5.1 dead, not posting, no chime

[Borowski]

Hi,

my friends MP5.1 does not starting anymore.
Symptoms: seems to start normally after pressing power button, white led is lit, fans running, HDD spinning, but no chime and no video output. Any input from keyboard has no effect. Also holding the power button does not set to firmware-programming mode.
We cross-changed the gpu and cpu-tray w/ mine MP, same problem, his tray&gpu work in mine. Battery was changed and measured, also ok.

When pressing the DIAG-button while switching on, leds are illuminated in this order:
5V STBY > GPU OK+PSU PWROK > EFI DONE > SYS PO

No red leds on cpu-tray, only very shortly if switching on or off.

Any ideas for trouble-shooting?

 

[Matty_TypeR]

I would swap power supplies first, between yours and his just to see if the PSU is not out putting its true output.
After that it would seem logic board failure, or boot rom failure.

 

[Macschrauber]

hold the diag button and turn the Mac on. The Diagnostic LEDs must show some sign of life. If they are just lit steady the backplane (maybe the firmware chip) needs to be checked.

 

[Borowski]

Hi,

we checked that, described in first posting, sorry if not clear: Pressing&holding diag button, then pressing power button. The leds will lit in the order: ac is connected, mac is off > pressing diag button > 5V STBY > pressing power button > GPU OK+PSU PWROK > EFI DONE > SYS PO. The leds will not switch off until release the diag button.

 

[Macschrauber]

yes, but they need to show some sign of living. I had dead backplanes what come with the Leds lit without moving in the early startup process.

So hold diag button and watch them. They need to live until the firmware has been executed and (if an Apple GPU is in) the gpu ok Led will lit when the uga driver was executed from the firmware of the gpu. This is usually the time when the big Apple is on the screen when loading the OS (with a bootscreen GPU).

 

[Garnett_Silk]

I have the same issue and was hoping this thread would continue. I then decided to remove all components and follow the steps outlined here: (I started a third of the way down the page "Minimum Configuration Testing") https://www.ifixit.com/Answers/View/559862/Mac+Pro+Won't+turn+on
I was getting set to start (6. Momentarily jump the SYS_PWR solder pads to turn ON the Mac Pro.) but as soon as I connect the power cord the "expected results" for step 6 all happen before I get a chance to jump the SYS_PWR solder pads.
Any idea why the following would happen before the SYS_PWR solder pads are jumped?
• Front and rear processor cage fans (and PCIe fan, if installed) should spin slowly
• One red-colored error LED illuminates on the processor board (next to the memory slots).

 

[Garnett_Silk]

I suspected the power supply so I picked one up on Ebay but the symptoms were the same. That's when I decided to do the tear down and rebuild.

 

[Garnett_Silk]

yes, but they need to show some sign of living. I had dead backplanes what come with the Leds lit without moving in the early startup process.

So hold diag button and watch them. They need to live until the firmware has been executed and (if an Apple GPU is in) the gpu ok Led will lit when the uga driver was executed from the firmware of the gpu. This is usually the time when the big Apple is on the screen when loading the OS (with a bootscreen GPU).

I tried holding the Diag button while connecting the AC cord for approx 2 minutes and there was no change in the Amber LEDs until I let go then they all shut off. If I am understanding correctly this sounds like a dead backplane. Would you agree?

 

[krakman]

No One mentioned the obvious:

1. doing nvram reset : hold alt + cmd + P + R on start up ( common thought is to hold the keys until the machine restarts 3 times)
2. Replace the Battery BR2032 that sits on the mother board behind the GPU
3. Clean all the dust out of the machine
4. Replace thermal paste on CPU / Check Northbridge heatsink

WIth regards to number 3 I had a red light on the CPU board caused by a bit of fluff that had fallen down into one of the RAM stick holders and was shorting out 2 pins on the RAM stick.

A good clean out later and no more red light and the computer showed I had 28 GB of Ram instead of 24.