VRM Caps? That is a Power Supply right?

[SkOrPn]

Hello again,

I have a question about cheap VRM caps (AMD Ryzen processor power supply VRM). I have a gifted motherboard (AB350M Pro4) that is well known to cut power to the CPU about every 10-15-20 minutes or so depending on how much air flow you force over the VRM. Since this is a Power Supply thread and VRM are Power Supply for a processor, I thought I would ask my question here. Should I move it to another section perhaps?

Can the below 4 pictured caps be replaced with far higher quality versions? I believe these caps have surpassed their heat rating limit (it started freezing at about the 7 Month mark, which coincides with the 5000 hour 105C rating on these caps?) and thus power is cut from the processor in order to protect it, or something along those lines. I am no real electronics tech but I do posses excellent soldering skills (trained by Intel for a full decade) and have a professional soldering setup. So since it is only 4 caps in total I would like to see if installing very high quality versions would solve the constant freeze/shut down issues that everyone with this board is experiencing. Thanks

Oh and I measured roughly 6.5mm in width by about 9mm in height. It appears I have space to go bigger too as they are about 1.5 to 2mm away from the chokes. So I could go to up to maybe 8mm in width if needed?

On the top of the caps it reads:

2.5 V
820
GW

I see no other marks of any kind on them. I just want to replace them with truly high quality caps, Rubycon or what ever is available. If it does not work I will sell the board on ebay as parts only and recoup my costs for the caps very easily of course.

Thanks again,
Rod

[SkOrPn]

Re: VRM Caps? That is a Power Supply right?

I think I will try replacing these caps with the below Nichicon's and hope I didn't make a selection error. lol

At least the capacitance, voltage and size are exactly the same. Tried going higher on voltage to 6.3v but other specs seemed to change on me. I guess I will always need active air flow no matter what I do. Asrock sure made these boards as cheap as they could.

Oh and I think these new ones are Solid Polymer and the old ones are electrolytic. I'm not sure on that though.

https://www.digikey.com/scripts/DkSe...49202706353956

[Stefan Payne]

Re: VRM Caps? That is a Power Supply right?

1. Link doesn't link
2. I don't think the caps are the issues.
With what you are describing the temperature of the VRM is. Or some other shit.

3. Your board is brand new, why the hell do you want to fiddle around with it instead of using RMA??

Oh and I think these new ones are Solid Polymer and the old ones are electrolytic. I'm not sure on that though.

That's just bullshit.

There are no wet electrolytics on modern Motherboards no more - even where they would make sense (Buffer Caps between Slots for the PCI(e) ones and USB/other connectors)

[momaka]

Re: VRM Caps? That is a Power Supply right?

I believe these caps have surpassed their heat rating limit (it started freezing at about the 7 Month mark, which coincides with the 5000 hour 105C rating on these caps?) and thus power is cut from the processor in order to protect it, or something along those lines.

While many polymer (and sometimes electrolytic) caps are usually rated for 2000-10000 hours, that doesn't mean that the caps would magically break / stop working after that period of time passes. Rather, this rating is often called "endurance", and typically it states the *minimum* amount of time that a capacitor will *stay in spec* at 105C temperature (typically) and the full rated voltage of the cap.

With that being said, you might ask, what happens to the cap if it runs at a slightly lower temperature than the maximum specified and at a lower operating voltage? The answer is, the lifetime increases greatly. For electrolytic caps, for every 10C you go lower in temperature (from the max rated), the lifetime (endurance) doubles. So a 2000 hour cap will survive 4000 hours at 95C. If you lower the temperature another 10C, the cap life increases to 8000h, and so on. I don't remember the figure/multiplier for polymers exactly, but I do remember it's much higher - meaning the life of the cap increases even more.

So that means it's very unlikely that your caps have gone bad. I personally have not seen a motherboard run its caps that hot to cook its caps in a year. Unfortunately, that means the problem is likely somewhere else. But what? - I have no clue when it comes to these newer motherboads. Frankly, I think they are all built like shit (even the "high-end" ones). I've tried troubleshooting several newer boards and never got anywhere. Unless you have a BGA problem with the CPU socket (which is one possible cause of your problem), there's not much else you can do really. The only other thing I can think of is a faulty chipset, especially if the motherboard has an AMD chipset (which I think it is, as I don't recall VIA, nVidia, or any other manufacturer making chipsets for AMD boards in the last 8 years or so now).

In any case, feel free to recap the board if you like. Maybe even go with 1000 or 1200 uF polymer caps with better ESR and ripple current, so you know all is good in terms of the filtering. But I am pretty sure that none of that will solve your issue. If for some odd reason it does (or seems like it), make sure to thoroughly test everything. Intermittent issues can sometimes make you believe that you've fixed a problem when you haven't.

[Stefan Payne]

Re: VRM Caps? That is a Power Supply right?

The only other thing I can think of is a faulty chipset, especially if the motherboard has an AMD chipset (which I think it is, as I don't recall VIA, nVidia, or any other manufacturer making chipsets for AMD boards in the last 8 years or so now).

Well, not really...
Technically the Promontory is an ASMedia Chipset. And not really that just an I/O Bridge with many things inside...

[SkOrPn]

Re: VRM Caps? That is a Power Supply right?

OK thanks for the replies gents.

And yeah it does clearly sound like a heat issue, which is why so many people can go from 10 minutes to 60 minutes if they only put a active fan blowing down onto the VRM's, but 60 minutes is not enough lol.

[Stefan Payne]

Re: VRM Caps? That is a Power Supply right?

Put a fan on the back, around the CPU Socket