Asus M2A-VM preventive KZG recap, as it turned out unnecessary in this case

[Exim]

This Asus M2A-VM was running 24/7 for 12 years without problems. CPU was a TDP 45W DualCore only, but still, 12 years are 12 years. I'm preparing this board as a spare part, it has to replace another one with blown caps. So before using it as a spare part it obviously needs to be checked. Because of the collection of bad caps usually on this board I was prepared for the worst.

Surprise #1: This particular board is an "almost-exclusively-Panasonic" specimen. It has the usual four 1000/16 Chemi-Con KZG plus three Chemi-Con KMA. Instead of the usual single Sanyo WX there's a Chemi-Con KZE. Everything else is Panasonic. VCore is the usual six Pana FJ, instead of the always bulging and failing 15 TK AWTY theres 15 Pana FJS, Audio uses a bunch of Pana HM and even the single poly is a (now) Pana OS-CON SEPC. I bought it new like this. Maybe it was a later run in the factory after they found out that the earlier ones died prematurely, I don't know.

So the only thing left to do was getting rid of the four KZG. I took them out and just for fun measured them. Surprise #2: All of them were within specs. After 12 years of 24/7.

It seems this particular M2A-VM was perfectly fine after 12 years of nonstop use. Including the KZGs. This was seriously unexpected. I know M2A-VMs that died withing the first two years.
However, since I already took out the KZGs I'll order Pana FMs as replacement.

Some pictures below.

[ChaosLegionnaire]

Re: Asus M2A-VM preventive KZG recap, as it turned out unnecessary in this case

yea, it seems that the 16v line of caps from the kzg and kzj series are fine for the most part, according to a post by momaka in another thread. click on the blue right arrow to view the thread and the post it came from.

The other interesting thing I noticed about Sanyo WF is that both 6.3V and 16V are equally prone to failure. From what I've observed, this is not so much the case with United Chemicon KZG/KZJ and Nichicon HN/HZ (with 2005 date codes.) In fact, I still have a lot of 16V, 1500 uF and 1800 uF KZG that test well in-spec for capacitance and ESR that are about equally old as these Sanyo WFs or even older. Some are still in use, too. Same with Nichicon HN caps with 2005 date codes that I've pulled from the same Xbox 360 boards - if it's rated for 16V, it hasn't given me problems. With KZG, the only exception is the small 16V, 470 uF on a few boards. But everything else rated for 16V has been mostly OK.

I'll order Pana FMs as replacement.

hold that thought because panny FMs wont fit as the 1000uF 16v part only comes in 10mm diameter. the kzgs are 8mm diameter caps. from your pics, the cap spots are either right up next to the coils or the mosfets and 10mm caps just wont fit in there. there's no space. the proper series to get would be panny FR 1000uF 16v 8x20mm or panny FS 1200uF 16v 8x20mm. those should fit and work fine!

[Exim]

Re: Asus M2A-VM preventive KZG recap, as it turned out unnecessary in this case

hold that thought because panny FMs wont fit as the 1000uF 16v part only comes in 10mm diameter. the kzgs are 8mm diameter caps. from your pics, the cap spots are either right up next to the coils or the mosfets and 10mm caps just wont fit in there. there's no space. the proper series to get would be panny FR 1000uF 16v 8x20mm or panny FS 1200uF 16v 8x20mm. those should fit and work fine!

Ah, you're right, that's the 8x20 KZGs, not the 10x16. I'll get some FRs then. regarding ESR and ripple KZG are 0.021/1870, FR and FS are 0.030/1560. Close enough.

[Per Hansson]

Re: Asus M2A-VM preventive KZG recap, as it turned out unnecessary in this case

It has been theorized and fits with my experience as well that Chemi-Con fixed the KZG series in 2008, they do not seem to fail.
I have also documented many times that the production line and date code even for their "bad years" matters, some date codes just soldier on...

[momaka]

Re: Asus M2A-VM preventive KZG recap, as it turned out unnecessary in this case

Surprise #1: This particular board is an "almost-exclusively-Panasonic" specimen.

Yeah, I've seen that on ASUS boards too. I too thought about some of my ASUS boards that perhaps they were later runs and maybe that's why they had better caps. But I think it might be more of, they used whichever caps they had on hand at the time, and some boards simply got nice Panny caps throughout, while others were littered with KZG (or worse, TK's.) On that note, it also depends who the board was made for. I think HP, being both a cheap and a premium PC brand at the same time, usually appears to carry boards with crappier brands - at least from all the ones I've seen (but I could be wrong on that.)

In any case, this was a nice surprise for you, I bet.

It seems this particular M2A-VM was perfectly fine after 12 years of nonstop use. Including the KZGs.

KZGs (and other similarly unstable ultra-low ESR caps) actually usually do slightly better when they are in use rather than sitting on the shelf and doing nothing. But I think the savior here is that your KZGs were 16V parts... and maybe also the fact that they may not have seen a lot of heat with that 45W TDP CPU. Could also be one of the "better" batches from the factory too.

But most importantly, it's not an nVidia chipset. When I saw the M2xxxxx in the model number, I immediately thought this board would be one of those nVidia GeForce 6100/6150 failboats. Luckily, that's not the case. Some of the newer AMD chipsets aren't that reliable either, but I think this one and the older Xpress 200 were pretty reliable if they had reasonable cooling.

Ah, you're right, that's the 8x20 KZGs, not the 10x16. I'll get some FRs then. regarding ESR and ripple KZG are 0.021/1870, FR and FS are 0.030/1560. Close enough.

Sounds good.
Though if you really wanted to, you probably could squeeze the 10 mm FMs in there. They'd just have to sit 2-3 mm above the board, as their leads would have to be slightly curved to fit in the smaller lead spacing. But really, looks like FS might be the winner here, as they offer slightly higher capacitance (1200 uF), which is always welcome on CPU VRMs.

It has been theorized and fits with my experience as well that Chemi-Con fixed the KZG series in 2008, they do not seem to fail.

Well, either that, or they improved them enough so that they don't fail as early. I guess we will have to see.
So far, I haven't seen failed KZG on newer boards either. Seems like after 2008-2009 is when they've been doing OK.

I have also documented many times that the production line and date code even for their "bad years" matters, some date codes just soldier on...

That's very interesting and actually seems to agree with some of my personal observations as well, because I too have some really old (2005-2007) gear with KZG that still appear fine visually and still works well too.

[Exim]

Re: Asus M2A-VM preventive KZG recap, as it turned out unnecessary in this case

It has been theorized and fits with my experience as well that Chemi-Con fixed the KZG series in 2008, they do not seem to fail.
I have also documented many times that the production line and date code even for their "bad years" matters, some date codes just soldier on...

That's very interesting and actually seems to agree with some of my personal observations as well, because I too have some really old (2005-2007) gear with KZG that still appear fine visually and still works well too.

What date(s) are printed on the removed ones?

while others were littered with KZG (or worse, TK's.)

But most importantly, it's not an nVidia chipset. When I saw the M2xxxxx in the model number, I immediately thought this board would be one of those nVidia GeForce 6100/6150 failboats. Luckily, that's not the case. Some of the newer AMD chipsets aren't that reliable either, but I think this one and the older Xpress 200 were pretty reliable if they had reasonable cooling.

Yes, they were. Or are. If the right caps were/are on.
Actually I liked the M2A-VM a lot back then. And I still do. It's an AM2 board with IGP and DVI-D, it has support for some AM3 CPUs and there's a version with an HDMI connector as well. PCIe is 1.1 only, but it already has SATA II / 300 Mbit. And Gbit LAN. With 8 GB of CL5 DDR2 RAM, a reliable SSD, an Athlon II X2 250 (AM3, K10, 3.0 GHz DualCore, 65W TDP) and VRAM size set to 256M or more this is a very nice and performant office machine, even today. Drivers might be an issue, but only on Windows 10 and maybe 8. With Linux it's perfectly fine, including the GPU firmware.
This board will go into such a machine with an AM3 CPU.

On the other hand: ATM I have another one of these boards, with just a "BE-2400" CPU (TDP 45W "PowerSave" variant of an DualCore Athlon 64) an no RAM. 15 TK caps need to be replaced. Would have to buy caps and RAM. The K8 CPU is not much of a powerhouse. Would have to get a decent CPU. And in the end I wouldn't need the machine/board anyway. I don't think I'll fix that other board. To me it's always the question "is it worth it". For just an M2A-VM without having the proper components already available I'd say "no". But that's just my view.

So far, I haven't seen failed KZG on newer boards either. Seems like after 2008-2009 is when they've been doing OK.

AFAIK KZG are still in production today, aren't they?

[Per Hansson]

Re: Asus M2A-VM preventive KZG recap, as it turned out unnecessary in this case

They are produced in June of 2007:

https://cdn.badcaps-static.com/pdfs/...ee3c51807e.pdf

[Exim]

Re: Asus M2A-VM preventive KZG recap, as it turned out unnecessary in this case

They are produced in June of 2007:

Nice, thanks for the link.


The new caps are on the board. Running some tests ATM.
Thanks for the comments. Much appreciated.

[RJARRRPCGP]

Re: Asus M2A-VM preventive KZG recap, as it turned out unnecessary in this case

That's very interesting and actually seems to agree with some of my personal observations as well, because I too have some really old (2005-2007) gear with KZG that still appear fine visually and still works well too.

Looks like 2004 (and possibly 2003) are the worst!