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Rafaellf

macrumors newbie
Original poster
Jun 3, 2023
9
0
Hello guys, I've just got home after a 2 days trip and found out that my Mac Pro won't turn on.
I left it turned off when I traveled.
It won't light up any light, make no sound, anything, its like its not connected to the power.
Ive tried different outlets but the result its the same.
Ive tried to check the led indicators, but it won't light any led.
I think the power supply gone bad, anyone have any tip to me?
Go straight to another power supply or is there anything I can test before?
 

h9826790

macrumors P6
Apr 3, 2014
16,628
8,557
Hong Kong
Hello guys, I've just got home after a 2 days trip and found out that my Mac Pro won't turn on.
I left it turned off when I traveled.
It won't light up any light, make no sound, anything, its like its not connected to the power.
Ive tried different outlets but the result its the same.
Ive tried to check the led indicators, but it won't light any led.
I think the power supply gone bad, anyone have any tip to me?
Go straight to another power supply or is there anything I can test before?
It's really hard to tell, but PSU is the first suspect.

If you can just buy a PSU replacement with reasonable price, IMO nothing wrong to try that first.

However, it can also be the logic board, or even just the power button itself doesn't work. So, if you can buy a whole used nMP with low price. I recommend you go for a whole cMP but not just the PSU. So that you have all the spare parts.

After you find out which part is bad, you can sell the remaining parts (if you want to).
 
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Matty_TypeR

macrumors 6502a
Oct 1, 2016
641
553
UK
You should use the BR2032 battery, same as what is fitted as standard, the CR2032 will not last very long. check battery voltage, anything below 2.8v is no good.
 
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w1z

macrumors 6502a
Aug 20, 2013
692
480
A problem with the cmos battery ? something like the CR2032 ?

You should use the BR2032 battery, same as what is fitted as standard, the CR2032 will not last very long. check battery voltage, anything below 2.8v is no good.

The CMOS battery does not play any part in this instance.

As @h9826790 suggested, it's most likely a dead PSU, logic board and/or cpu processor board.

@Rafaellf Is this a 5,1 or 7,1? and do you have power surge protection in your setup?
 

tsialex

Contributor
Jun 13, 2016
13,218
13,394
It's a late-2013 Mac Pro. The light that the OP is referring to is the illuminated back panel of the MacPro6,1 and not the diagnostic LEDs that you need a magnet to make it work. Also, the thread tag is MP6,1.

A MacPro6,1 does not start complete POST without a RTC battery and with a failing one, it crashes and beeps when you try to enter sleep.
 
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tsialex

Contributor
Jun 13, 2016
13,218
13,394
Ive tried to check the led indicators, but it won't light any led.

Did you followed the Apple Technician Guide instructions and used a magnet to make the late-2013 Mac Pro to work without the case installed?

You can download the Apple Technician Guide from this thread:

 

w1z

macrumors 6502a
Aug 20, 2013
692
480
It's a late-2013 Mac Pro. The light that the OP is referring to is the illuminated back panel of the MacPro6,1 and not the diagnostic LEDs that you need a magnet to make it work. Also, the thread tag is MP6,1.

A MacPro6,1 does not start without a RTC battery and with a failing one, it crashes and beeps when you try to enter sleep.

Ahh, missed the tag .. thanks for pointing it out.

As for the CMOS battery - you'd have startup issues, yes, as in the mac pro powers up but won't complete its startup sequence and crashes. Never heard of a missing or dead CMOS battery affecting the powering up of a mac let alone a pc. It's not even interlinked with the power rail.
 
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Rafaellf

macrumors newbie
Original poster
Jun 3, 2023
9
0
Did you followed the Apple Technician Guide instructions and used a magnet to make the late-2013 Mac Pro to work without the case installed?

You can download the Apple Technician Guide from this thread:

I'll try that right now! Any specific magnet kind? Or I can try with a random one?
 

tsialex

Contributor
Jun 13, 2016
13,218
13,394
As for the CMOS battery - you'd have startup issues, yes, as in the mac pro powers up but won't complete its startup sequence and crashes. Never heard of a missing or dead CMOS battery affecting the powering up of a mac let alone a pc. It's not even interlinked with the power rail.

Ok, let me be completely clear.

A MacPro6,1 will not complete POST without a RTC battery and the Apple Technician Guide warns about it, see item 8 page 24:

8. Coin battery
  • Computer does not keep time when unplugged
  • No boot

The lowest voltage that the MacPro6,1 still boots with a failing RTC battery is 2.7V.
 

w1z

macrumors 6502a
Aug 20, 2013
692
480
Ok, let me be completely clear.

A MacPro6,1 will not complete POST without a RTC battery and the Apple Technician Guide warns about it, see item 8 page 24:



The lowest voltage that the MacPro6,1 still boots with a failing RTC battery is 2.7V.

I beg to differ.

OP reported no power and no lights.. no power ≠ no boot. No boot means powering on but not booting up (running boot sequence / loading OS into memory). Same thing applies to POST - Powers on first then completes or fails to POST (which is part of the boot process) hence no boot.
 

Rafaellf

macrumors newbie
Original poster
Jun 3, 2023
9
0
Never needed anything special, just get a magnet at least the size the one that the case have.
alright, I tried with a refrigerator magnet (the decorative ones) and got nothing, not sure if this magnet is weak or anything.
I read the manual and looked for the diagnostic leds, the #2 led lights up when I press the diag button and that's all.
I've tried the magnet thing while pressing the diag button and I still get the same, only the #2 led lights up.
On the manual I've read about the coin cell battery check, and I will try that as I have an multimeter, I'm just not sure how, the manual indicates a test point and I assume that's where the red tester from the multimeter should go, I just don't know where to put the black tester.
 

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tsialex

Contributor
Jun 13, 2016
13,218
13,394
On the manual I've read about the coin cell battery check, and I will try that as I have an multimeter, I'm just not sure how, the manual indicates a test point and I assume that's where the red tester from the multimeter should go, I just don't know where to put the black tester.

Any screw nearby, see the image below, is connected to the GND plane and can be used as ground for your black multimeter tip.

Screen Shot 2023-06-15 at 12.35.00.png


Also, if your multimeter is not RMS, the cutting point for the RTC battery voltage needs to be 11% greater, so, 2,997V
Strike that, RMS versus average only matter for AC.
 
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Rafaellf

macrumors newbie
Original poster
Jun 3, 2023
9
0
I've got a magnet tool like the one showed on the manual to test the diagnostic leds and yet got the same result, only led #2 will light up when I connect a/c power, if I press the power button while holding the magnet and pressing the diag button nothing else will light.

I want to test the power supply with a multimeter, I know that I should use the power bars, where should I place the ground? (@tsialex hope you can help)


-----
I managed to take out the power supply and test it with the multimeter, the max I've got was 0.2V, I think it's a bad PSU, will order one.
 
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Rafaellf

macrumors newbie
Original poster
Jun 3, 2023
9
0
Coming back with an update.
I've just replaced the PSU and didn't work.
Don't know what I should replace next.
 
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