Sidebar Sidebar
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

backplane change in MacPro 4.1

D

daavYo

macrumors newbie
Original poster
May 29, 2016
29
5
Hi all
since my 4.1 wont start
- no chime, tried the graphic card, the system, the ram no go -
i bought a backplane board (200$ with shipping outch) & i want to replace mine

any advice, help, videos ?
i found on youtube a 1.1 mother board change but since it's different ...

thanx
 
Nice. That is an updated service manual that I didn't have. I just followed an old one to swap a board and found two issues with the instructions. I see the first simple one is fixed which was that they now show 10 screws holding the backplane when they used to show 9. Second they added a note to the first steps that was missing - "Disconnect power supply cable from backplane board. Refer to Power Supply in Take Apart."
 
Well ...
i changed the backplane - gratitude for
carpsafari

it was long but so easy with the service manuel
but ... when everything was assembled back & connected
no power !! meaning no effect on the power button - no light, nothing
i have a spare power supply, i changed it also
nothing !!! (i tried the diagnosis button - the power light on board lit when pressed)
grrrrrrr
i took down everyting thinking i d forgotten something
then i assembled back the old backplane board
wishing for a miracle
but same symptoms
power button is back on, light above the button, fans ok but thats it
no shime, or something else

1-do you think the new backplane is faulty ?
2- any suggestion ?
:(
 
Your welcome, a pity it did not work.
For $200 I expected a working backplane, with warranty or at least option to sent back.
Unfortunately you see many vague adds.
Does look like a non working backplane.

As you say, the service manual is very clear and you did not run into a big problem (brittle connectors), so I believe its not your work that is at fault!
Did you also use a fresh pram battery?
But no power at all, does not look good.

I would check the connectors again, to see if they are making contact...I received a MP 3.1 that booted just fine, but non of the HDD bays were seen,...I found that one of the connectors wasn't attached just right,..after that the problem was solved.
[doublepost=1500027791][/doublepost]Some thoughts;

You are sure it is a 2009/4.1 backplane board?
Your 4.1 wasn't flashed to 5.1 firmware yet?

If you did flash your 4.1 to 5.1, its likely the 'new' backplane is still 4.1 and that also could be a reason why it isn't working.
 
i changed the battery (only once though)
i extra checked for the connectors - all of them

i suspected the cable from front panel board and backplane board
since this one give the power to the power button
but no (effects discribe before)
:(
 
Just added this;
You are sure it is a 2009/4.1 backplane board?
Your 4.1 wasn't flashed to 5.1 firmware yet?

If you did flash your 4.1 to 5.1, its likely the 'new' backplane is still 4.1 and that also could be a reason why it isn't working.
 
I'm curious: what made you think it was a bad backplane board to begin with? Did you investigate the power supply? To me, that would have been my first troubleshooting step.

It seems since with a replacement backplane board it still does not boot, I would suspect it's not the backplane board at all; neither the original nor the replacement.
 
  • Like
Reactions: h9826790
Well, obviously you did not read his posts, because after trying he did try another PSU as well!!
[doublepost=1500030860][/doublepost]See, for $149 they do sell boards with a 30 day return warranty.
http://www.ebay.com/itm/Genuine-Use...ng-/282105170166?_trksid=p2349526.m2548.l4275

I don't know where you are located.

PS, it looks like this is a 'good' example of sellers not knowing themselves what they sell, because it looks like a 1.1/2.1/3.1 board! But they describe A1289...go figure.
 
Last edited:
carpsafari said:
Well, obviously you did not read his posts, because after trying he did try another PSU as well!!
Click to expand...

Well obviously, you are simply assuming that the power supplies are fully functional. A simple "power status LED" does not mean the PSU is not faulty in another way to prevent system start. The same error in assumption was what confounded Apple when they couldn't figure out the power problems of my own 5,1 and they instead pursued backplane replacement, processor board replacement, video card replacement, and finally 2xCPU replacement. They gave up when none of that solved the problem. Had another shop look at it and after they replaced the PSU with a new one (not used, not refurbished), problem solved.

But hey, each situation is unique.
 
Last edited:
Auggie
i tried everything
graphic card, ram, processor tray(inspected, & processor lifted but not tried on another mac) ...
then i read that could be the power supply
i bought one (150€ ! a used one) but same symptoms

the new mother moard is a 4.1 (ou 5 ?????)
i didnt upgrade the firmware
(i was thinking about upgrading the processor but i didnt)
pffffffffff

thanx for your help
 
I also doubt why you can conclude is the logic board failure.

Even though you have extra PSU to test it and rule out PSU failure. This power on but no boot symptom can still be CPU tray failure.
 
why PSU failure ?
i thought so, so i changed it but same symptoms
(light on the power button but no chime)
could both PSU be not OK ?

you re right concerning the CPU tray, but i couldnt find another mac
to try out the CPU tray :-(
& since everything looks ok there ...

i guess that will be my next move
 
Don't you know anybody close to you with a 4.1?
Even a 5.1 would do, just to test the tray, although the fans will go crazy.

I would have checked the tray prior to what you did now.

PS, you can check the Northbridge module, if a rivet snapped, that would also be a reason why it won't boot.
 
Last edited:
daavYo said:
why PSU failure ?
i thought so, so i changed it but same symptoms
(light on the power button but no chime)
could both PSU be not OK ?

you re right concerning the CPU tray, but i couldnt find another mac
to try out the CPU tray :-(
& since everything looks ok there ...

i guess that will be my next move
Click to expand...

Even though the chance is rare. Did you try to boot without graphic card? A GPU failure can cause the same symptom, but the computer will boot and run headless without graphic card installed.
 
this is what i looked for, Carpsafari
the north bridge look intact, doesnt move a bit
both rivet are here

i'm in paris, i can ask a mac reseller if he d let me try

the graphic card is good mac one
tried it on a 1.1,
i got other pc graphic cards wich work on 1.1
wich i tried on the 4.1, same thing

i suspected the mother board since i left the mac sleeping (without turning off) few times for more than a week
without touching it
at some point the power button light would go blinking
but when using it again no problemo
[doublepost=1500058885][/doublepost]do you think the backplan board i bought is faulty ?
since i got only the diagnosis button showing a light
the power button doesnt seem to react - no light when pressed
 
  • Like
Reactions: Synchro3
daavYo said:
at some point the power button light would go blinking
Click to expand...

Well, this usually indicates bad ram.
[doublepost=1500059954][/doublepost]
daavYo said:
do you think the backplan board i bought is faulty ?
Click to expand...

That's what I assumed, but I would check the Processor Tray first, before I go to find another backplane board.
I would be surprised if a Reseller would even have an MP 4.1/5.1
 
Last edited:
ram is quite recent
& the blinking went only when the mac was asleep
not during normal use
 
Ram; when you start the MP, all red leds on the Tray should blink for a second.
Power blinking usually indicates ram, but without connection to CPU's it will also blink.
The Northbridge you can exclude when the rivets are OK.
And the tray itself can fail too.

So you see there are several options for just a failing Processor Tray...and that is before you can conclude the Backplane is failing.
 
sorry i was trying

i think the ram is ok, no red light on the memory board
i also tried some old ram sticks, with the same result
 
No problem man, I know its like looking for a needle in a haystack, but better to exclude the Tray before you change the backplaneboard.

I'm talking about the red lights blinking for a second, is an indicator all is well! (also the cpu leds!)
In your case you don't get to the point where you can check the ram, that is usually after the Boiing and as it doesn't make a sound....you still cannot exclude the ram either!

But as the old ram also doesn't work, go to step 2 and test the tray!
 
sorry for the suspens
i didnt find a macpro where i can try the processor tray
& i was thinking about changing the processor - about 60€
 
You must log in or register to reply here.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.
Top Bottom
Back