Preemptively Recap Motherboard?

[Uniballer]

An ASUS M2N68-AM PLUS motherboard is being used to manage environmental controls in a range of greenhouses. It's a pretty good board for that purpose because it has a parallel (printer) port, serial port, PCI and PCIe slots, gigabit ethernet, can use unbuffered ECC RAM, etc.

The caps for the CPU VRM are polymers, but there are UCC KZG caps on the board. None appear to be bulging and leaking, and the board seems to work fine at this time. Should I preemptively recap the KZG's? Or leave it alone unless it starts misbehaving? I have a blue ESR meter, and a DE-5000 LCR meter, but feel that if I have to pull the caps to test them then I might as well just replace them. What do you think?

[mockingbird]

Re: Preemptively Recap Motherboard?

I would worry more about the fact that it uses a known defective nVidia chipset...

If I were you I would look for an alternative. M2A/M3A series boards are far more reliable because they use the AMD chipset. Regarding unbuffered ECC ram, do you mean that you specifically require a board that supports ECC capability? I ask this because if you must use unbuffered ECC modules because that's all you have, all boards should accept those modules, even the ones that don't have the ECC capability.

[Uniballer]

Re: Preemptively Recap Motherboard?

I would worry more about the fact that it uses a known defective nVidia chipset...

...Regarding unbuffered ECC ram, do you mean that you specifically require a board that supports ECC capability?

Yes, for stuff that runs 24/7 (e.g. environmental controls, telephone PBX) I use ECC RAM and expect it to actually correct single bit errors and hopefully never have to report double bit errors. Some of the board manufacturers do not support ECC even though the chipsets do.

Tell me more about the chipset problems. I have put four of these boards into service for various people and haven't heard of any problems, but they all run cool. Are the problems heat related? Or something else? I read that there were problems with the Nvidia 65nm and 55nm designs, but I believe that the parts on this board are 110nm. More information would be appreciated.

[Pentium4]

Re: Preemptively Recap Motherboard?

I think it's a good rule of thumb to always replace KZG the second you see them. They often go bad without symptoms. If it hasn't seen a ton of use, I'd recap it, and reapply thermal paste to the chipset at least, look for a bigger heatsink for it if you can.

And always remember that Asus PCB's make it look like the caps are installed backwards, so always check and double check polarity when recapping

[mockingbird]

Re: Preemptively Recap Motherboard?

Tell me more about the chipset problems.

Ok, but I should first point out that eventhough the CPU is made by AMD, there were two chipsets during that time that were used, nVidia and AMD. And that is what I mean by M2A and M2N. Boards with the 'n' in it have the nVidia Northbridge.

There were a few problems with their manufacture... Firstly, nVidia was undergoing a stage of managerialism and decided to cut costs by firing engineers. This resulted in a chip that was designed in a way that it could not radiate heat out properly. Secondly, they used the wrong metals to make contact between the substrate and the die. Thirdly, they used the wrong underfill.

I have put four of these boards into service for various people and haven't heard of any problems

Don't worry about it then, but keep it in mind for the future if you ever have to replace them. I agree with Pentium4 that you should in fact preemptviely re-cap them. Regarding which generation are affected, it is anything after nForce4 (Socket939), so your generation is definitely affected.

Having said that, keep in mind that YMMV. I have an HP mini PC with a minature motherboard that uses a chip from that generation and AFAIK it has been running flawlessly for years (After I re-capped the MB and PSU). OTOH, I was once called upon to inspect a bunch of computers of identical spec that invariably suffered from random crashes because of it. They were all scrap as far as I was concerned.

[Uniballer]

Re: Preemptively Recap Motherboard?

OK. I will recap 'em as time allows.

I don't know how much it matters but the board is used as a headless controller. Users talk to it with a web browser. The onboard video is in text mode, and not doing anything much. I assume this greatly reduces the chipset heat output, and probably nobody would notice if the video output failed as long as everything else kept working. The parallel port is cabled to an OPTO-22 PB16H board to control discrete outputs. There are additional serial ports installed to communicate with remote sensors and control modules via 1-Wire.

[kc8adu]

Re: Preemptively Recap Motherboard?

sounds as if it has a rather easy life.it might live a long time that way or puke its nb and caps tomorrow.caps are easy.nb,mcp not worth it.

[Uniballer]

Re: Preemptively Recap Motherboard?

caps are easy.nb,mcp not worth it.

Agreed.

Aside from the 820uF 6.3V KZGs and the polymers there are only Panasonic 100uF 16V CMHs, and one Panasonic 470uF 16V FJS. I assume that I can leave the Panasonic caps alone.

Would you say Nichicon HNs to replace the KZGs (polymers would be twice the price)? Or is there a better value?

[Pentium4]

Re: Preemptively Recap Motherboard?

You can leave the Panny's. And 820uF 6.3V nichicon HN are a perfect replacement, they have slightly lower ESR and a little more ripple current

[c_hegge]

Re: Preemptively Recap Motherboard?

It's thermal cycles that kill the chipsets usually. If it sees 24/7 use, it's only going through 1 thermal cycle in its life, and it will probably have a long life.

[Uniballer]

Re: Preemptively Recap Motherboard?

The first board went fine, except I couldn't get the soldapullt in deep enough between the PCI slots. I had to heat up the vias and push the cap in a little at a time. That took longer than I was comfortable with heating the pads but nothing broke.

[Uniballer]

Re: Preemptively Recap Motherboard?

The second board I looked at was loaded with Panasonic FJS caps instead of the UCC KZGs, so I didn't mess with it. There's no visible flux or anything on the board so it's either a really professional grade recap or (more likely) FJSs from the factory.

[Uniballer]

Re: Preemptively Recap Motherboard?

The third board is full of KZGs, so I stuck in a spare board I had already recapped and I'll recap the one I pulled out before checking the fourth.

[Uniballer]

Re: Preemptively Recap Motherboard?

I bought a couple more boards on ebay for another headless controller application. Both of these boards have TK 6.3V 820uF 105 degree C caps. They also say ATWY 024A. Are these any good? Or should they be replaced, too? I still have plenty of the Nichicon HN caps.

[c_hegge]

Re: Preemptively Recap Motherboard?

TK is even worse than KZG IMO. I've seen that many of them fail after 2 or 3 years on boards which have only had light use that I always replace them.

[mockingbird]

Re: Preemptively Recap Motherboard?

Hey Uniballer,

Are the $6 Chinese knock-off Soldapullt as good as the $20+ ones? Or are the $20+ ones just the $6 Chinese ones with brands on them?

BTW, I sold that M2A-VM I picked up in the trash a while back. It replaced an HP-Branded M2N with a defective chipset. The M2A-VM had a visibly damaged internal USB header (open SMD fuse and burnt ceramic cap), but that wasn't a problem because I didn't need all the internal USB headers. What irritated me though was that one of the memory slots was dead, so I couldn't make use of dual-channel mode.

For that I knocked the price down for the replacement from $75 to $60 (I re-capped that M2N the client had before for a steeply discounted price beforehand, and also tinkered with the PSU, so I felt $75 was reasonable), and I also upped them to a dual-core Athlon and more RAM to sweeten the deal.

$60 for picking it up on the curb and a little work.

[stj]

Re: Preemptively Recap Motherboard?

what's a "Soldapullt" ??

if you mean a pump,
i have a weller pro-desold that costs about $25,
i'v seen *exactly* the same pump at DX for about $5 and a better built one for about 50c more.

[stj]

Re: Preemptively Recap Motherboard?

o.k. - found it.
those are dangerous - you can get hit by the plunger.
if you dont mind that, DX has those too - a friend has one.

[diif]

Re: Preemptively Recap Motherboard?

I've been looking at the ss-02 for desoldering, i like the idea of the silicone at the end to get really close to the job.
http://www.amazon.co.uk/innovative-s...ds=desoldering

[Uniballer]

Re: Preemptively Recap Motherboard?

Are the $6 Chinese knock-off Soldapullt as good as the $20+ ones? Or are the $20+ ones just the $6 Chinese ones with brands on them?

I don't know. I can't remember actually using anything but the Soldapullt pumps since around 1983. I did pick up an OK Industries pump for 1$ at a flea market (it's really an Introvac SP made in Sweden, and so clean I bet it's never been used), but I don't think I've actually used it (yet). Both of those designs protect the user from the plunger hitting them on release. The Soldapullt protection is better IMO because the back end of the plunger is fully enclosed.

If a cheaper Chinese pump works just as well then that's OK with me. The biggest things that are good about the Soldapullt are the self-cleaning action (the tip of the plunger pushes solder flakes out when the pump is cocked), strong suction, the user protection, replaceable teflon tip, tool-free teardown and reassembly, and the fact that it is long lasting and reliable. I use Permatex 22058 Dielectric Grease on the O-ring when needed. It's cheaper than the Edsyn grease and seems to work just as well.

EDIT: I just bought one of these to try out. I'll report back on it if I remember .

M2A-VM ... $60 for picking it up on the curb and a little work.

Good job!

I've been looking at the ss-02 for desoldering, i like the idea of the silicone at the end to get really close to the job.

That pump does not protect the user or surroundings from plunger impact on release. I go right ahead and push the Edsyn teflon tips right up against the iron, but maybe it could melt if you leave it there too long.