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Dead 4,1/5,1 cMP Power Supply?

UCDHIUS

UCDHIUS

macrumors regular
Original poster
Nov 16, 2017
199
61
Texas
Power supply has been intermittent sometimes it would boot up no problem.


Other times psu would “click” on then click off with no life.


Most of the time it would start if the power button was pressed 10-20 times.


Sometimes it will turn on if started by rapidly unplugging and plugging back power cord in at a rapid pace.

If shut down it would act the same way, but if shut off and started back up (within 5 seconds) it would start no problem.


Verified main AC power, tried different power cord.


I can hear a faint electrical (buzz) nose coming from power supply area when power button is pressed.

But no status lights, clicks or anything.

Dead power supply or something else?

How many have had a 2009-2012 power supply fail?
 
Your symptoms can be from dying logic board too. I bought one power supply thinking that was he problem but was the logic board.
 
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tsialex said:
Your symptoms can be from dying logic board too. I bought one power supply thinking that was he problem but was the logic board.
Click to expand...

For future reference

Do you know what’s the the latest part number is for the 2009 backpane board?

I’m seeing part number 661-4996? Is this the latest version? The reason I ask, is they are label “version 1”.

Was there a newer “version 2” made for the 2009 4,1?
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AliGT83 said:
Maybe result from the overclocking you have performed on your Mac Pro?
Click to expand...

Possibly, however I don’t see any burnt components or out of the ordinary indicators on the backpane board.

If I remember correctly it was acting up when I first received it in 100% original form. But I didn’t think anything of it as it was a one time thing.

I have to do further testing, as far as the overclock itself it shouldn’t interfere when the machine is booting up from a cold boot.

As it has to be manually applied, every reboot.
 
UCDHIUS said:
For future reference

Do you know what’s the the latest part number is for the 2009 backpane board?

I’m seeing part number 661-4996? Is this the latest version? The reason I ask, is they are label “version 1”.

Was there a newer “version 2” made for the 2009 4,1?
Click to expand...

Yes there is: http://tim.id.au/laptops/apple/macpro/macpro_early2009.pdf

Backplane Board:
Ver. 1 661-4996
Ver. 2 661-5444
Click to expand...

I have one 4,1 B08 manufactured at the end of July 2010, I can check tonight for the part number on it.
 
tsialex said:
Yes there is: http://tim.id.au/laptops/apple/macpro/macpro_early2009.pdf



I have one 4,1 B08 manufactured at the end of July 2010, I can check tonight for the part number on it.
Click to expand...

Do you know what, if any differences “version 2” has over the original “version 1” board had?

Seeing that they are the same price, and if the back pane board is indeed dead. (Still have to test) I might as well go for the version 2 board.

This is originally a early 2009 4,1.
 
UCDHIUS said:
Do you know what, if any differences “version 2” has over the original “version 1” board had?

Seeing that they are the same price, and if the back pane board is indeed dead. (Still have to test) I might as well go for the version 2 board.

This is originally a early 2009 4,1.
Click to expand...
Don't know if there is any hardware components diffs between versions, BootROM has many, but I can look if I have both and try to find it.
 
Have you ever taken the PSU out of the cMP and de-dusted it ?

( don't touch anything inside the PSU .. capacitors can give you a nasty shock ).
 
MIKX said:
Have you ever taken the PSU out of the cMP and de-dusted it ?

( don't touch anything inside the PSU .. capacitors can give you a nasty shock ).
Click to expand...

The ODD caddy is stuck and I can’t seem to get it (ODD caddy) out any tips?
 
So I was able to get the PSU out, no dust and doesn’t smell burnt.

Using the diag button on the backpane board. The 5V led does light up yellow when pressed and AC power is hooked up.

This morning it started up no problem into macOS after a few power button presses and “clicks” after being unplugged over night.

It did randomly shut off, after running in macOS for 1-2 hours.
 
Did you actually use CANNED AIR to blow any hidden dust out ?

I used a soft brush to de-dust the fan blades too.

You can safely remove the side covers = beware of capacitors.

I went over my 2009 cMP's PSU with a fine toothed comb .. so to speak, seemed to fix quite a few problems
 
Thoroughly clean & de-dust the old PSU. . it may be OK .. mine was. Be careful not to touch any condensers, they keep a charge for a long time,
 
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