Need Mac Pro 2009 - 2012 PSU Pin out

DrBobF

macrumors newbie
Original poster
Mar 27, 2014
5
0
CT
Greetings - I'm trouble shooting a 2009 Mac Pro for a no power up problem. The apple custom 980Watt delta power supply pinout is proprietary but the major power rail positions are evident. ( +12/ GND... GND/ +!2 ) The center group of smaller pins have two conductors that when shorted together will power on the PSU, which is, I think, the " power on" signal, normally supplied by the mother board. In the process of load testing the PSU on the bench to check the current spec.
Does anyone have the full pin out of these center group of conductors?

Update... I just did a quick load test on the PSU using a 100watt load on each of the 12V rails and forcing the PSU to turn on with the two pins I spoke of.
PSU seems to be working at this load and being when it is put back into the chassis with only the motherboard, front and rear panels installed with the 5VSB led lighting when the diagnosis button is pressed, it seems the the power on signal to the PSU is not happening. It seems either a connection issue on the mother board or a failure of the power on button/ circuit. A schematic would be handy to troubleshoot this.
 
Last edited:

DrBobF

macrumors newbie
Original poster
Mar 27, 2014
5
0
CT
Thanks for the information. I just put the PSU on the test bench and shorted the two pins ( must be the "Power On" signal ) out and the PSU turns on. With a fractional load of ~100W on both the A and B outputs, the 12volt rails are stable. Must be a connection, motherboard or front panel issue. Without any of the proprietary ( Not even to developers ) schematics , it is time to get out the DDM and analyzer to see what is not happening. Thanks again. Cheers.
 

Macschrauber

macrumors 6502a
Dec 27, 2015
768
299
Germany
A Mac Pro 5.1 board set runs without the front panel. I just put together a backplane board, prozessor board and of course a gpu, a usb boot device and got it booting. No fans, no front panel and no case. I just had to shorten the power on pads on the board.

Please share what you can sort out, i am too lazy now (without a reason) to put out a PSU for more measurings :)
 
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zcream

macrumors member
Sep 8, 2008
43
6
Thanks a ton. Any idea how that maps to the rails from the rear? I might connect to a molex connector by soldering from the rails
 

donluca

macrumors regular
Jul 30, 2018
183
92
Italy
Credit to Jason Ling Ling King.
View attachment 851601
Holy moly, this is a godsend, we can now try getting a Custom PSU together and see if it works! 4,1 and 5,1 PSUs are dying like flies those days and a proper PSU means having no needs to do pixlas mod, just route the cables!

Hopefully someone will get on this and shed some light, especially on the Pin 8 which supplies... 5.12V? Uhmmm...
 

Trail-Hawk

macrumors newbie
Jan 25, 2020
5
0
Any updates on this at all? Did you find the issue and was it the PSU? Currently have a 2012 pro tower, when AC is connected two red diag lights at the top of the back plane board come on and stay on. Perhaps after 5 mins go off. machine then takes a few power button presses - lots of clicking then will boot. All fans run full tilt. Will get into os however after about 2-3 mins will shut down. 12v power rails appear to fluctuate 12.2 to 12.4v approx and a small faint constant click from the PSU but hard to determine if that’s the actual fault at this point. Would be great to know what those diag lights are. I can find that particular code description anywhere. Thanks.
 

Snow Tiger

macrumors 6502a
Dec 18, 2019
854
563
Any updates on this at all? Did you find the issue and was it the PSU? Currently have a 2012 pro tower, when AC is connected two red diag lights at the top of the back plane board come on and stay on. Perhaps after 5 mins go off. machine then takes a few power button presses - lots of clicking then will boot. All fans run full tilt. Will get into os however after about 2-3 mins will shut down. 12v power rails appear to fluctuate 12.2 to 12.4v approx and a small faint constant click from the PSU but hard to determine if that’s the actual fault at this point. Would be great to know what those diag lights are. I can find that particular code description anywhere. Thanks.
What are the colors of the following LED diagnostic lights that stay on constantly ? Not worried about brief flashes . These two banks of lights are located on the upper left portion of the logic board

Mac Pro 4,1 and 5,1 ( Nehalem ) BackPlane Onboard LED Diagnostic Indicators :

Upper bank :

OVTMP CPUA
OVTMP CPUB
PSU PWROK
5V STBY
3.3V ( No light installed )
1.5V ( No light installed )
1.05V ( No light installed )


Lower bank :
SYS PG
PLT RS ( No light installed )
X1 PG ( No light installed )
EFI DONE
GPU OK
5V ( No light installed )
RSM RST ( No light installed )

During normal operation , the PSU PWROK is green , the 5V STBY is amber , the SYS PG is green and the EFI DONE is green .
 

Trail-Hawk

macrumors newbie
Jan 25, 2020
5
0
OVTMP CPUA
OVTMP CPUB

Both Red as soon as mains turned on. Not sure if status when I get it to fire up I’ll have to check this, but at the moment it does not want to fire up at all. These leds are staying on longer where before they would go out after some time. When they went out you could press the power button a few times to get it going. When they are on however press the power button and nothing. Removed cpu tray and they are still the same. SonInam thinking either psu or backplane. But would be good to know what these two lights mean. Whe diag button is pushed get the amber led light up.
 

Kelinu

macrumors newbie
Apr 13, 2020
8
0
Hey everyone, I have a Macpro 5.1 which has been giving me some power issues. It turned off on its own...than after several tries managed to power it back up only to turn off again a few minutes later. Than again managed to turn back on but did not boot and had a the front LED flashing. Since then, completely dead. Tried RAM modules, changing CMOS battery and resetting SMC to no avail. I am now reverting to troubleshooting my PSU. I followed the steps as per Macschrauber's diagram above and tried reading between pins 12 and 2 and result was 0V. Does this automatically PSU is dead? Sorry not a schooled electrical engineer here just like to try out by myself so any hints/tips would be highly appreciated. Thanks!
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Trail-Hawk

macrumors newbie
Jan 25, 2020
5
0
Make sure you trigger the PSU correctly you should be able to hear it click on. I tracked
down the issue on mine, faulty caps on the back plane board leaked down the board and caused a huge corrosion mess. You only could really tell one the board was pulled. Through my learning curve if the voltage check on the PSU comes up ok, it’s more than likely the backplane faulty.
 

Kelinu

macrumors newbie
Apr 13, 2020
8
0
Make sure you trigger the PSU correctly you should be able to hear it click on. I tracked
down the issue on mine, faulty caps on the back plane board leaked down the board and caused a huge corrosion mess. You only could really tell one the board was pulled. Through my learning curve if the voltage check on the PSU comes up ok, it’s more than likely the backplane faulty.
Hi Trail-hawk thanks for your reply. I'm plugging the PSU normally (still in the chassis). Didn't hear any click though. I want to make sure that I'm taking the right readings (from the correct pins). As I said, pins 12 and 2 gave me 0V. Pins 12 and A gave me 3V. Does it make any sense?
 
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