Question Generally speaking - What are the symptoms of a PSU problem if the system still works (sometimes) ?

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TrufflesG

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A new twist to this story has emerged.......

Apparently, the MOBO is not as old as I thought. It's only a year and a half old.
I called ASUS and they looked up the Serial and told me it was under warranty for another year and a half WOOT !!!!!

BUT (and it's a big but)....
I have to first start clean and reinstall Windows because ASUS says this problem I'm having is well known and is almost always related to the OS (Windows 10)
This is what the Tech Support rep said.

So I'm going to buy a new SSD and install a fresh Windows 10 on that and run it a while and see.

What do you guys think about the ASUS Tech Support advice? Likely the problem?
 

USAFRet

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So I'm going to buy a new SSD and install a fresh Windows 10 on that and run it a while and see.
 
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TrufflesG

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I wouldn't be that confident. You replaced one junk-tier PSU with another one.

And damage can be indirect; the GPU can be damaged, damage caused by the first junk PSU.

Are you using an APU or a CPU? You haven't even told us what CPU you're using in the board.
It took me a while to get over my stubbornness and ignorance but I see now that you were correct.
Makes more sense to me now that I'm a little more educated about the problem.
Thanks
 

TrufflesG

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I never found "the problem" here.

But I did have a low end PSU that was about a year into service in this machine.
My suspicion is that the PSU caused a spike and that caused the issue.
Then again, it always possible a component failed on the MoBo.

That said, I'm considerably more knowledgeable with electronics now and have since learned how to test Mosfets, capacitors, optocouplers etc etc and have a good bit of equipment to do so. By no means an "expert" but ahead of where I was before for sure.

Out of curiosity, I may dismantle the board and individually test all the components just to satisfy my curiosity.
I know now that mosfets handle the majority of the switching so those would be suspect.
They could also be a source of a large enough surge to cause that big pop I heard.

Depending on the topology, another mosfet might be handling it's load and explain why it's still working.
I also have an O-scope now (several actually) and might check their output signals.

Truth be told....I may never actually nail down the cause. I just hope it doesn't happen again.
Top Tier PSU's might have filters to prevent this..then again top tier PSU's probably would not have that problem due to better design and better components.

You get what you pay for.

The MoBo is still under warranty and it's going back to Asus.
Not sure if they have a machine specifically for testing the board to find faults or if they just replace it.
Seems far cheaper for them to just replace it. The per unit cost on these boards is probably very low for them.

I wonder what the general consensus (or luck) others have had in general sensing MoBos back to Asus for repair / replacement ?
 

TrufflesG

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Dismantle which board?
The motherboard, or the PSU internals?
PSU.
I've dismantled some boards far more complex with lots of SMD components.
Redesigned some in KiCAD and got new boards made at JCL.
I can even resolder 0805's pretty good now lol.
This is a very simple switch mode power supply.
If there's a bad Mosfet it would be easy to tell. Looking at the wave form on the O-scope might be even more interesting.
And btw.....I'm no expert, just a determined hobbyist.

The MoBo is on it's way back to Asus for repair.

Other than salvaging a few SMD caps there's not much I could do with that MoBo.
If I could find the ALC1220 I could try replacing that but all I see on a quick Google search is a generic (non Realtec) ALC1220.
But that would be a stab in the dark. Could be any of 1000 things.

Neither Mouser nor DigiKey sell that chip so I don't know it's availability.

Makes me really wonder what Asus customer support can actually do.
They would have to have some really serious equipment to diagnose such a problem.
They may have something that tests all the major sub systems but as far as getting o-scope waveforms on each one I doubt they have the time for that nor would it be cost effective.

These boards probably don't cost them much. I'm guessing around $30 - $40 at their cost. Just sending out another new board might be their cheapest course of action. They may have a refurb shop that does some testing and repairing but my gut feeling is that it would be hit or miss.
That said, I don't have any experience with Asus repair service and don't know the success rate of their warranty return program.
If they sent me another "used" board that had other problems I would be SOL since the warranty is a one time deal I think and my warranty period would have expired.
 
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TrufflesG

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I don't know what you plan to do in there, but PLEASE don't go inside the PSU.
It's ok.
I respect your concern and appreciate your thoughts.
I've worked on MANY PSU's and switch mode power supplies.
I make sure to discharge any high voltage capacitors.

Often times I work with them fully powered while I do diagnostics.
You just have to know what you're doing. I do...mostly :)
Anyone can. Just a matter of dedication to learning.
Always eager to learn from those further along of course.

I also use an Isolation transformer often.

Electronics has been my hobby for several years now and I do a lot of repairs on broken electronic equipment.
Switch Mode Power Supplies (PSU) units is where I've spend the most of my time.
Also Battery Backups like APC etc.
Truth be told, these new MoBo's are in another league and I don't do much with them.
But I can replace smd IC chips, capacitors and such if it warrants it.
They are so complex that it is difficult to diagnose problems unless it's obvious.
Sometimes applying the respective voltage at the power inputs and checking the outputs of certain IC chips can reveal a problem. Or rapid heat build up on short circuits
Still, sometimes all it boils down to is another learning experiment with these complex micro smd MoBos

In fact, it was about the time of this MoBo failure or maybe about a year before, that I got into electronics which was a couple years ago.
Now my shop looks like an electronics repair center lol
 
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TrufflesG

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Follow up:
I ended up trying a new ROG Strix MoBo in this system and it STILL misbehaved.

AFAIK the only thing I didn't test was the cpu and I don't see how it could be anything else at this point.
I ordered another Ryzen cpu and I'm sending the questionable one back to AMD since it's still under warranty.

If by any chance I still have this issue with this system after replacing the MoBo, the CPU, GPU, RAM, PSU, SSD and disconnecting ALL unessential peripherals etc..........

Then this is definitely a case of "The Issue was confirmed to be caused by evil Ghosts" and not a hardware, software or user problem.
 
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