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Siski125

macrumors member
Original poster
Oct 19, 2021
47
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Hi all!! I've been looking on YouTube, web FB etc.... and I don't see any documents on fixing Mac Pro 5.1 power supply even after all these years and yes I know that there isn't any schematics for it but still is it because some parts you can't get or just a waste of time? I know you can get some 2nd hand on eBay and other places on the net but still find it odd no one seems to have tried to fix it like I said no docs, no vids nada, nothing, zippo. The reason why I'm asking is that I think that my power supply is failing on me slowly and the reason why that I think is because a few days ago I noticed that when I turn it on I used to hear a loud "click" turn on sound and it's been 3 days now and the click sound is now about half of what it used to hear so I THINK this is a sing of a failing power supply. Is there other sings that I should be aware of? So anyone know a site that document's on how to do you own repair either vid or docs would be nicely welcomed!! BTW I did get a 2nd PS on eBay just in case yesterday. I'm not asking for any schematics because I know there isn't any (thanks Apple).

Thanks for any info!!!

Serge
 
Mine is doing almost the same thing .....if turning on after being off for a while you hear the normal click but the front LED does not come on. I then hold the power button until it clicks off . Then try again it turns on normal with no issues .
if it goes into extended sleep ...same problem won't wake. Tried new battery.
also tried looking for repair info
 
Could the power supply need recapping (replacing aging capacitors)? I know capacitors dry out after several years, and it's a common repair procedure for vintage electronic musical equipment (synthesizers, drum machines etc) so I wouldn't be surprised if that applies to Mac power supplies as well...
I may be way off here and the problems lie elsewhere, but thought I'd mention it.
 
I'm kind of curious of why this thread even exists. The OP already knows that there is no electrical circuit/schematic available from Apple or 3rd party, why even ask if the PSU is fixable?

Besides very simple and easily identifiable problems, you can't really repair a Mac Pro PSU and a person that doesn't have the training to do it can easily die from electrical shock.

Btw, recapping a failed Mac Pro PSU thinking that will magically repair it will get you nowhere and will be a very expensive/time consuming/risky endeavor.
 
I'm kind of curious of why this thread even exists. The OP already knows that there is no electrical circuit/schematic available from Apple or 3rd party, why even ask if the PSU is fixable?

Besides very simple and easily identifiable problems, you can't really repair a Mac Pro PSU and a person that doesn't have the training to do it can easily die from electrical shock.

Btw, recapping a failed Mac Pro PSU thinking that will magically repair it will get you nowhere and will be a very expensive/time consuming/risky endeavor.

I curious as to why you feel this way. While I 100% agree with the statement highlighted in red someone who is familiar with recapping electronics equipment and high voltages shouldn't have any issues. Likewise I don't think that it is unreasonable to think it would fix the problem. I've recapped a number of Apple II power supplies and that fixed them. Is there something unique about the Mac Pro power supply which would make such a task unrealistic?
 
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I curious as to why you feel this way. While I 100% agree with the statement highlighted in red someone who is familiar with recapping electronics equipment and high voltages shouldn't have any issues. Likewise I don't think that it is unreasonable to think it would fix the problem. I've recapped a number of Apple II power supplies and that fixed them.

You are comparing a Ford-T with a McLaren F1. :p

Is there something unique about the Mac Pro power supply which would make such a task unrealistic?

Simple, the complexity. Open a MacPro4,1/5,1 PSU and take a good look.

The ACBel have an older design based on MacPro3,1 PSUs and is more easily understandable, but the Delta design is newer and a lot more complex.

Besides that, recapping is not a magic bullet. While boards that have capacitors with fake electrolyte should have it replaced, like Amigas with SMD caps and a lot of late 90's early 2000s Mac logic boards, it's not something that I would do as a general rule.
 
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You are comparing a Ford-T with a McLaren F1. :p



Simple, the complexity. Open a MacPro4,1/5,1 PSU and take a good look.

The ACBel have an older design based on MacPro3,1 PSUs and is more easily understandable, but the Delta design is newer and a lot more complex.

Besides that, recapping is not a magic bullet. While boards that have capacitors with fake electrolyte should have it replaced, like Amigas with SMD caps and a lot of late 90's early 2000s Mac logic boards, it's not something that I would do as a general rule.
I agree that technology has improved but capacitors still dry up and fail. Unfortunately I do not have a failed Mac Pro power supply of which to open. But if I did I certainly would and I may even think about recapping it.

Do I hold recapping up as a panacea for all that ails failed power supplies? Certainly not but it's not an unreasonable failure to consider and, IMO, it's not an expensive repair.
 
I agree that technology has improved but capacitors still dry up and fail. Unfortunately I do not have a failed Mac Pro power supply of which to open. But if I did I certainly would and I may even think about recapping it.

My pointy is to never stimulate people that don't known better to mess with caps that have over 2KV stored months after disconnected from power.

Do I hold recapping up as a panacea for all that ails failed power supplies? Certainly not but it's not an unreasonable failure to consider and, IMO, it's not an expensive repair.

It's more expensive than getting a working 2nd hand PSU, even if you are doing the service yourself. People always forget the cost of your own time, supplies and replacement parts…
 
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My pointy is to never stimulate people that don't known better to mess with caps that have over 2KV stored months after disconnected from power.

I agree that it can be dangerous if you don't know what you're doing.

It's more expensive than getting a working 2nd hand PSU, even if you are doing the service yourself. People always forget the cost of your own time, supplies and replacement parts…

For most people I would agree. However, you questioned why this thread exists. Well, presumably it exists because the OP has an interest in repairing the power supply. Recapping doesn't seem like an unreasonable thing to inquire about. At some point 2nd hand power supplies will become expensive or unavailable.
 
However, you questioned why this thread exists.

In a more appropriated forum, like the repair section of eevblog, a thread about Mac Pro PSUs should definitively exist - but not here.

At some point 2nd hand power supplies will become expensive or unavailable.

Sure, but it's not the case at the moment since 2nd hand PSUs are a lot cheaper than the components used to make it.
 
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In a more appropriated forum, like the repair section of eevblog, a thread about Mac Pro PSUs should definitively exist - but not here.

Given I see other kinds of repair inquiries and advice I see nothing wrong with his having asked the question.

Sure, but it's not the case at the moment since 2nd hand PSUs are a lot cheaper than the components used to make it.

Perhaps but that does not invalidate his question.
 
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Did you try swapping it out?
Nope the "click" came back to normal (maybe dust or someting). BTW I got myself a 2nd hand PS and I'm waiting for another one.

Ok now I don't understand why some people here always have a negative response to this question. YES I KNOW that Apple DOESN'T provide ANY SCHEMATICS AND I KNOW how to DISCHARGE CAPS I'm not that DAFT!!! I'm a strong believer of recycling and if it can be fixed then you don't need to toss it to the trash and then it gets to a landfill. I've saved allot of electronics that would otherwise been tossed into the dumps because some people don't have the time to fix it or not knowledgeable to fix it. I have TIME and PATIENCE to do this like some here don't seem to have. Instead of saying something negative/rude here then just don't say anything ok and pass on. We should HELP each other here instead of putting us down no mater how stupid the question may be for some, we don't have a level 100 IQ in intelligence here so please we should be all as equal here no mater how knowledgeable we are or not. I took a chance here IF EVER there was someone who would of attempted to repair one that's all nothing more. We are all APPLE FANS here right? Then why not help each other as family, is it too much to ask?

I want to say THANKS for those who have responded me in a "nicely" way again THANKS!!!

Sisko
 
@Siski125, or anyone else who planned to toss your defective power supply, would you please DM me and ship to me? I am working on something on my end with my two defective power supplies that I have, to analyze it and figuring out a solution. What I need is dying power supply with clear definition of the issue it is having. I cannot do anything on the dead ones. That's what I meant by saying defective instead of dead. Thank you.
 
Has anyone made any progress in this topic?
My cMP 5,1 power supply is working fine for now, but being over 22 years old I can't help but worry that the capacitors may be near their end of life, so as a preventive measure it might be a good idea to replace them before the whole PSU fails (and possibly also damages something else in the process).

Has anyone opened their PSU to take a look inside? It's been a while since I took my cMP apart, but IIRC I had problems opening it for some reason that slips my mind (I'm usually quite curious, so I open up things like this to take a look).
 
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Has anyone made any progress in this topic?
My cMP 5,1 power supply is working fine for now, but being over 22 years old I can't help but worry that the capacitors may be near their end of life, so as a preventive measure it might be a good idea to replace them before the whole PSU fails (and possibly also damages something else in the process).

Has anyone opened their PSU to take a look inside? It's been a while since I took my cMP apart, but IIRC I had problems opening it for some reason that slips my mind (I'm usually quite curious, so I open up things like this to take a look).
The only progress was to buy one for now BUT yes replacing the caps would be a good idea. If I were you I’d buy a spare one just in case that it dies on ya. Yeah your like me curious to see what’s inside but I just love to fix stuff so take your time to open it up and don’t force anything.
 
I haven't seen any used PSU units locally, and buying one from abroad would probably cost half a fortune, so that would be a little tricky.
But basically, if you get the same (or better spec'd) capacitors in similar physical sizes, take notes of their positions and polarities on the PCB, have suitable desoldering/soldering equipment and know how to discharge them before doing the job it should be a relatively straightforward job IMHO.

But of course, without any schematics, photos or documentation it would mean opening up the unit first, take notes/measurements, order and then open it up again and proceed.
 
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