What backplane boards work in Mac Pro 5,1 ?

Jdebunqe

macrumors newbie
Original poster
Apr 17, 2017
9
1
I have a 2010 Mac Pro 5,1 with a quad 2.8 GHz CPU.

The backplane board is dead.

I want to salvage this machine, cheaply. But 5,1 logic boards are expensive ($300). A 4,1 board costs only about $120. It's the same part number, but EEE code is BH9, different from 4,1 boards.

Is there any chance that a 4,1 (2009) board will work in an otherwise 5,1 machine? This is a 2010 with the lowliest old-style CPU, so my thinking is that it MIGHT not need the new CPU support of the 5,1 backplane.

Would the machine work with a 4,1 backplane with upgraded firmware? Would it boot enough to upgrade the firmware (given the old-style CPU), or would the firmware upgrade have to be done beforehand on a 4,1 machine?

Finally, what is the underlying difference between between an upgraded 4,1 backplane and a genuine 5,1 backplane? I heard something about the fans running full all the time, because of different SMC firmware. Can this be upgraded too? I've read that a 4,1 backplane is forever a 4,1 even if upgraded? Is this true, and why?

Thank you for any tips, or any link that explains these issues in detail.
 
Last edited:

Jdebunqe

macrumors newbie
Original poster
Apr 17, 2017
9
1
No, the SMC firmware won't match. If you buy a 4,1 logic board, you have to buy a 4,1 CPU tray as well (including the heatsink etc).
This is the rough answer I've seen already, but the nitty gritty questions I'm really interested in are

  1. is SMC firmware something that can be upgraded?
  2. is the minimal 4x2.8 2010 CPU tray the same as a similar 2009 board (this is the barebones CPU that didn't change, if I understand correctly)?
  3. Will firmware mismatch result in a non-boot, or merely problematic operations (eg fans on all the time) that will permit a firmware flash?
  4. If (question 1) you can upgrade SMC firmware as well as board firmware, can you turn a 4,1 logic board into one that is indistinguishable from a 5,1 board?
  5. This one is far out - is there a chip that can be swapped from the dead 5,1 board to put the new firmware on a 4,1 board?

Is there a site that fully explains these firmware issues?

This site: https://support.apple.com/en-us/HT201518 seems to suggest that there are no SMC versions for a 4,1 or 5,1.
 

Filin

macrumors regular
Mar 7, 2010
135
37
Ukraine
This is the rough answer I've seen already, but the nitty gritty questions I'm really interested in are

  1. is SMC firmware something that can be upgraded?
  2. is the minimal 4x2.8 2010 CPU tray the same as a similar 2009 board (this is the barebones CPU that didn't change, if I understand correctly)?
  3. Will firmware mismatch result in a non-boot, or merely problematic operations (eg fans on all the time) that will permit a firmware flash?
  4. If (question 1) you can upgrade SMC firmware as well as board firmware, can you turn a 4,1 logic board into one that is indistinguishable from a 5,1 board?
  5. This one is far out - is there a chip that can be swapped from the dead 5,1 board to put the new firmware on a 4,1 board?

Is there a site that fully explains these firmware issues?

This site: https://support.apple.com/en-us/HT201518 seems to suggest that there are no SMC versions for a 4,1 or 5,1.
1. Last firmware for 4.1 has different SMC version (1.39F5) than 5.1 has (1.39F11). And after hack upgrade from 4.1 to 5.1 version of SMC remain the same (1.39F5). Not known, how to update SMC version from 1.39F5 to 1.39F11
2. There is no 4 CPU tray. Only single and double. Dual CPU trays a very similar, but have different heatsinks (not interchangeable).
3. It should boot, but all fans will go crazy. You can flash firmware, but firmware will not change SMC
4. SMC cant be upgrade easy
5. Sure, but it soldered on board.
[doublepost=1492465798][/doublepost]
Is there a site that fully explains these firmware issues?
Try read here http://forum.netkas.org/index.php/topic,13595.0.html
 
Last edited:

Jdebunqe

macrumors newbie
Original poster
Apr 17, 2017
9
1
Thanks! I meant "4-core 2.8 GHz tray" when I confusingly wrote "4x2.8 2010 CPU tray".

This is the information I was looking for: that the 4,1 and 5,1 boards are identical, but it is not possible to change the SMC firmware. It seems that anyone who figured out how to convert 4,1 boards to 5,1 with chip update would make some nice cash.

Is there any info about which chip the SMC firmware lives on? In case I get drunk enough to mask off the board and hot-air the chip off the old board and onto a cheap 4,1 board?
 

ActionableMango

macrumors G3
Sep 21, 2010
9,520
6,774
Just a thought, but are you certain the backplane board is dead and not something else like the power supply?
 

Filin

macrumors regular
Mar 7, 2010
135
37
Ukraine
Is there any info about which chip the SMC firmware lives on? In case I get drunk enough to mask off the board and hot-air the chip off the old board and onto a cheap 4,1 board?
You should look "board view" file for 820-2337
It not easy to find (for free).
 

Jdebunqe

macrumors newbie
Original poster
Apr 17, 2017
9
1
Just a thought, but are you certain the backplane board is dead and not something else like the power supply?
Power supply and cpu board work in my other 2010 mac, and it fails the "strip down machine and jumper contacts X and Y so the fans spin" test from the service manual.
 
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Jdebunqe

macrumors newbie
Original poster
Apr 17, 2017
9
1
Thanks ... I ended up getting a cheap 2010 backplane and it fixed my machine very nicely.

If you could figure out how to reprogram this chip, you could probably earn $70 a board turning 4,1 into 5,1!
 
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