MSI K9N DIAMOND Repair

[Pentium4]

Got this "As is" at a local electronics outlet for $4.95. By looking carefully you can see bulged Teapo SEK, Teapo SC, and Sanyo WF on the VRM High side.

Teapo are crap anyways, but the PSU powering this comp probably was sending out bad ripple on the 12V to kill those Sanyo WF caps on the 12V input filtering.

[Pentium4]

Re: MSI K9N DIAMOND Repair

I replaced the Teapo SC 100uF 16V caps, 470uF 6.3V Teapo SEK, and the two Sanyo WF 1000uF 16V caps with 270uF Sanyo SEPC polymers. Board POST's now.

[mockingbird]

Re: MSI K9N DIAMOND Repair

Looks like some KZG too. I'd take off the heatsink/heatpipe too, then clean it and give it soem nice fresh thermal compound.

[Wester547]

Re: MSI K9N DIAMOND Repair

Sanyo WF don't actually have a good track record and I don't think they're reliable (I have seen supposedly genuine Sanyo WF bulge and leak on unused GX270 motherboards that were never recapped). A search on this forum will turn up an alarming listing of bloaters. I'd guess that WF (equal to HN) is probably less durable than WG (equal to HM) as WG is rated up to double the lifetime in accordance to the datasheet (up to 4,000 hours vs. 2,000 hours). All that to say, VRM input failures are somewhat rare as even crap brands and series usually do okay there provided they aren't under too much thermal stress or that they haven't been abused so yes, the PSU output capacitors might be at fault. As to Teapo, 4mm-8mm Teapos seem to fail much faster than 10mm-18mm Teapos... that being said, it's pretty sad when KZGs (visibly) outlast 6mm Teapos.

Then again, on very old (but unused) Foxconn boards built for Intel, I have seen 13mmx25mm 2200uF 16V Teapo SCs (in the VRM high) outlast (visibly) KZGs (10mmx25mm, 3300uF 6.3V, VRM low)....

Any idea what brand the PSU was?

[Pentium4]

Re: MSI K9N DIAMOND Repair

Looks like some KZG too. I'd take off the heatsink/heatpipe too, then clean it and give it soem nice fresh thermal compound.

Those KZG are next to go now that I know the board works. And I also plan on reapplying the thermal paste with MX2. The fan was also seized on the northbridge. I have a new 40mm one that I oiled, which should be nice for it, cause it got hot quickly with no fan on it.

All that to say, VRM input failures are somewhat rare as even crap brands and series usually do okay there provided they aren't under too much thermal stress or that they haven't been abused so yes, the PSU output capacitors might be at fault.

Exactly what I was thinking. I've recapped TONS of Intel DG41TY boards, and they always had 1500uF 16V KZG on the VRM high, I never once found one that bulged or tested bad. Granted, just on this board, but I've seen a lot of them because that's mostly what my company put in new builds from 2008-2009.

While I'm at it, I will replace the other 1000uF WF caps on the VRM high. I'm going to assume that all those Rubycon MBZ will also be okay, I like this board, but I really don't want to replace all those Rubycons, because there's already a lot of KZG to replace. I have a nice Athlon 64 x2 6000+ that I'm going to throw in there, and install 8GB of 667 RAM. Should be a nice setup.

I'll post more pictures when I'm done

[Pentium4]

Re: MSI K9N DIAMOND Repair

Forgot to mention, the bulged WF caps read 322uF 0.90Ω, and 229uF 1.12Ω. I figured they would have been worse than that, at least resistance wise

[momaka]

Re: MSI K9N DIAMOND Repair

Very nice score!
Gotta love MSI motherboards - such great designs and ususally only ruined by a few bad cap brands/series. I mean, just look at that beefy VRM design - 4-phase and 16 FET. And I am sure it runs stone-cold too (at least I haven't seen an MSI motherboard with a badly-designed VRM yet).

Yes, those Rubycon MBZ caps should be fine. Even MCZ is okay most of the time if they have not been abused by heat. The KZGs need to go, though. I only leave KZG if they are used for filtering USB port power lines and don't look bad.

[Pentium4]

Re: MSI K9N DIAMOND Repair

Wow you're right, there really is 16 FET's there. Impressive! I'll see how warm it gets with the new CPU once I'm done recapping it. I tend to like MSI motherboards as well. The KZG's were just left till I knew the board was working. The BIOS won't keep its settings even with a good CMOS battery. Maybe one of those caps nearby is affecting that?

[momaka]

Re: MSI K9N DIAMOND Repair

Looks like there are three polyfuses and three KZG caps next to them next to the BIOS chip, so I am guessing that's for USB/Firewire front headers and not the problem. I don't see any CMOS reset jumpers though. I assume that's what SW1 is for? Maybe see if it's stuck (check with a multimeter). Other than that, perhaps unstable 3.3V standby (most motherboards generate a 3.3V standby rail from the 5VSB). On older MSI boards, IIRC, that's usually done between the PCI/PCI-E ports via a few MOSFETs and caps. With the motherboard plugged in to a PSU but in soft-OFF mode, there should be 3.3V on at least one or two MOSFETs.

[Teeri]

Re: MSI K9N DIAMOND Repair

You had it easy. My media server suddenly died today and I found 8 bulged/burst capacitors inside! Newer seen so many, so bad caps in a motherboard that has still worked recently whit out any issues. I am still hopeful to repair this thing, as I really don't want to recover my RAID array.
I am going to get some low esr Panasonics from my LES tomorrow, so SWMBO will get her TV shows recorded.


I am going to stock up enough cap's to change them all if necessary, but will start only with the obvious ones as I am lazy and in a hurry. The server is (way long over) due to some HW upgrades anyway, so maybe it will last until then. Also if it breaks up again, maybe the financier will be more willing to spare some funding for new toys.

[stj]

Re: MSI K9N DIAMOND Repair

panasonic dont make electrolytics with low enough esr for a VRM, you need to use poly's

[momaka]

Re: MSI K9N DIAMOND Repair

panasonic dont make electrolytics with low enough esr for a VRM, you need to use poly's

In a pinch, Panasonic FR and FM will probably do. Yes, polymer caps would be better, particularly in any buck-type regulators (which I see this board has a few, besides the CPU), but for the rest even mid-grade low ESR caps will do.

Just get rid of all Teapo and Chemicon KZG, that's for sure.