Recapping a DFI nF4 Ultra-D

[mitchmaster]

I have this motherboard that won't post and I have decided to try and fix it. The last time I saw it working must have been Oct/Nov 2014 and when the PC didn't turn on any longer I just blamed it on the PSU because I didn't really care to investigate why it wasn't working.

Last week I finally did decide to investigate what was wrong and I noticed two bulging caps near an auxiliary power connector, they are KGZ 1500uF 6.3V which I understand are bad. One has the bung popping out also but apparently it didn't leak on the PCB.

I thought I may as well replace ALL the capacitors while I'm at it in order to avoid future failures but I don't know if it's really necessary so I need a few directions.

Let's get to it.

On the board there are 61 electrolytic caps and 8 polymer caps (these are all 560uf 2.5V, brand unknown, A 54J if it rings any bells).

I'm attaching a few pictures for your viewing pleasure. In one I indicated the values of all the lytics, the original picture (here) is from the Techpowerup review of the board (check it here if you want to see close-up shots of the board) although the PCB revision is different. In the other two pictures you can see the two bad caps.

The two bad KZG and the other five KZG caps near the ATX connector are going to go, but I would like to know what you guys think of the other caps on the board, if they need replacing or not. I can guess what a certain cap does but I can't really tell where the VRM or other sections begin or end so I need some guidance. And the polymer caps are staying, right?

If you have any questions or need more info, just ask.

Thank you

[Stefan Payne]

Re: Recapping a DFI nF4 Ultra-D

Replace KZG with polymer caps.
And the KY can be replaced with 'normal' low ESR caps of equal value...

Are those Nichicon all HM series?
HM seems to be equal to NCCs KZG, so it's best to replace them with polys as well.

Or similar, long life, ultra low ESR caps...

[ReeceyBurger123]

Re: Recapping a DFI nF4 Ultra-D

Ky should be fine they are UCC's best series IMO but replace all HM & KZG.

[mitchmaster]

Re: Recapping a DFI nF4 Ultra-D

Replace KZG with polymer caps.
And the KY can be replaced with 'normal' low ESR caps of equal value...

Are those Nichicon all HM series?
HM seems to be equal to NCCs KZG, so it's best to replace them with polys as well.

Or similar, long life, ultra low ESR caps...

Ky should be fine they are UCC's best series IMO but replace all HM & KZG

Thank you for pointing out that the Nichicon HM are bad, I tought they were good caps

About replacing them with polys though... I'll look into it but since there are 34 of them that would cost more than the board is worth.

I know of the half-capacitance rule for replacing lytics with polys when they are in the VRM, but to which capacitors on my board other than the KZG should I apply it? What about that lonely Nichicon 1000/6.3 to the right of the two bust KZG 1500/6.3 in the middle of the board?

Thank you

[mariushm]

Re: Recapping a DFI nF4 Ultra-D

HM and HN are good series of capacitors.

However, there was a small time period around 2002-2004 if I remember correctly when the Nichicon factories used too much electrolytic (or some other substance) inside these series of capacitors which made them failed prematurely.
Capacitors made after somewhere around April-May 2004 (again, if I remember correctly) from those two series are good.

If they're failing or failed on motherboard, it's not due to technical faults but due to other reasons (for example whole pc overheating or power supply giving bad quality power to the motherboard.

There's usually a datecode on the capacitors (4 digits), the first two are the manufacturing week and the other two are the year, that should tell you if you MUST replace the caps, or if you just SHOULD (if you want to replace with polymers)

Also, HM and HN were discontinued recently by Nichicon but big stores like Digikey should still have some in stock. Nichicon recommends HW series as replacement for the two (and indeed it works well for most cases) but you can use polymers instead if you want.

KZG series is just bad, it's one of the series that has lowest esr possible, and my guess is the electrolyte inside is of another formula compared to their other series, and this formula wasn't quite stable. They're known to fail even without usage, just by sitting on shelves or in boxes.

[Stefan Payne]

Re: Recapping a DFI nF4 Ultra-D

Still, I'd do every cap I'd come across, just to be safe...

But the question is what mitchmaster wants to do...
Does he want to get rid of the 'bad caps' or does he want to do a real capjob??

[mitchmaster]

Re: Recapping a DFI nF4 Ultra-D

I'm going to do a real capjob

I'm planning to replace the KZG caps with polys and all the others with lytics. Going full poly would be too expensive.

The supplier I chose to buy from (that would be RS) has a lot of stuff but many types of capacitors are sold only in packages of 10 or 25 and up and I don't need that many, so the selection was somewhat reduced. Anyway, these are the caps I have selected for now.

KZG 1500uF 16V >>> Panasonic OS-CON 1000uF 16V 16SEPF1000M
KGZ 1500uF 6.3V >>> Nichicon L8 FPCAP 1000uF 6.3V RL80J102MDN1KX

Nichicon HM 1000uF 6.3V >>> Panasonic FM 1000uF 6.3V EEUFM0J102
Nichicon HM 470uF 16V >>> NIC Components NSRG 470uF 16V NRSG471M16V10X12.5F
KY 470uF 6.3V >>> Panasonic FC 470uF 6.3V EEUFC0J471
KY 1000uF 16V >>> NIC Components NSRG 1000uF 16V NRSG102M16V10X20F
KY 100uF 25V >>> Rubycon ZLG 100uF 25V 25ZLG100MEFCT16.3X11 (I fear these at 6.3mm diameter are too big, gotta check)

Are they looking good?

[mariushm]

Re: Recapping a DFI nF4 Ultra-D

I wouldn't use NIC Components caps. See if you can replace those 470uF 16v with 270-330uF 16v polymers
You could also do better with the 1000uF 16v selection. You could use 1000uF 16v for the 1000uF 6.3v capacitors as well, if that will allow you to buy a larger pack of same capacitor, just be careful at the distance between leads.

I don't normally do this because it's a lot of wasting time at the post office but if your problem is the minimum quantity on RS and you have a Paypal account to pay me, I'd be willing to mail you some capacitors from my own personal stock (bought in 2015 from Farnell and Digikey, but i keep them properly stored so no issues).

I have 100uF 16v Panasonic FR capacitors (5x11mm) or 120uF 50v (8x15mm) to replace your 100uF/25v caps, 470uF/25v Panasonic FM because it's common combination in lcd monitors, but you could use instead of 470/16 as long as they fit (i think 10x12mm , may have some 8x16mm but not sure until i check boxes) and I should have 1000uF 16v Panasonic FM (10x20mm)

If you're interested let me know, i bought them in large quantity (50-100+) so price would be less than RS, plus maybe about 2$ for postage.

[mitchmaster]

Re: Recapping a DFI nF4 Ultra-D

Thank you for your kind offer but I think I'll just leave the HM and KY caps where they are and replace the KZG.

I have found problems with the size of most of the caps I had chosen and buying different types would cost too much. It was already over 30 € with tax and shipping and I don't want to spend even more money on a 10-year old board.

I checked the data code on the HM caps and they are all A0520 and A0531, and since I bought this board in November 2005 I assume that 05 is the year and 20 and 31 are the weeks so they should be good.

Maybe I'll change them at a later time

[ReeceyBurger123]

Re: Recapping a DFI nF4 Ultra-D

No REPLACE THE HM ! They are known defective, you will just be fixing it again in a few months times even if they are 2005 +

[mitchmaster]

Re: Recapping a DFI nF4 Ultra-D

I hear you, I'll look into it and I'll let you know.

[mitchmaster]

Re: Recapping a DFI nF4 Ultra-D

Okay I'm getting Panasonic FR caps to replace the HM, and I'm keeping the KY caps.

[RJARRRPCGP]

Re: Recapping a DFI nF4 Ultra-D

There's usually a datecode on the capacitors (4 digits), the first two are the manufacturing week and the other two are the year

The last two being the year is American format, lol. (WW-YY)

International format is YY-WW

[Stefan Payne]

Re: Recapping a DFI nF4 Ultra-D

HM seems to be similar to NCC KZG, so you need a similar ultra low ESR series...

I think the newer KZE series could be OK, but I'm not sure (and I don't want to take a look at the Datasheets)...

You should worry more about ESR than the capacitance of the cap...
You probably would be fine with a smaller cap if the ESR is similar...

[momaka]

Re: Recapping a DFI nF4 Ultra-D

Okay I'm getting Panasonic FR caps to replace the HM, and I'm keeping the KY caps.

That should work fine.

Panasonic FR and FM series are not quite as good as Nichicon HM, but they are reasonably close, especially FM. Not to mention FR and FM have much longer endurance lifetime, so they can take a little more abuse than the HMs. An alternative to FR and FM would be Nichicon HW.

However, the closest option (besides getting new Nichicon HM or HN again) would be Rubycon ZLG, or if you don't mind old stock - MBZ. Chemicon has a new series for motherboards too - KZA. But I wouldn't jump on them just yet. They could have the same unstable electrolyte as KZG/KZJ.

And yes, leave the Chemicon KY. They are non-aqueous electrolytic caps and extremely stable. Shouldn't need to touch them for another decade or possibly even longer.

HM seems to be similar to NCC KZG, so you need a similar ultra low ESR series...

I think the newer KZE series could be OK, but I'm not sure (and I don't want to take a look at the Datasheets)...

Chemicon KZE has slightly more inferior specs to both Panasonic FR and FM. It has the same exact specs as Nichicon HD and Rubycon ZL.

No REPLACE THE HM ! They are known defective, you will just be fixing it again in a few months times even if they are 2005 +

Disagree here.
Nichicon HM caps made after (and including) 2006 are fine. It's the ones between 2001 and 2004 that are *definitely* problematic. With 2005 ones, take out a coin, call heads or tails, and flip it - some have problems and others don't. Same goes for HN and HZ, especially when they sit on a shelf with no voltage applied.

[Wester547]

Re: Recapping a DFI nF4 Ultra-D

However, the closest option (besides getting new Nichicon HM or HN again) would be Rubycon ZLG, or if you don't mind old stock - MBZ. Chemicon has a new series for motherboards too - KZA. But I wouldn't jump on them just yet. They could have the same unstable electrolyte as KZG/KZJ.

KZA is described as having the same "super low resistivity" electrolyte as KZG and KZJ and looks to be KZJ's replacement. KZA isn't that new though - went into production around 2008 or 2009.

And yes, leave the Chemicon KY. They are non-aqueous electrolytic caps and extremely stable. Shouldn't need to touch them for another decade or possibly even longer.

Not really. KY are definitely on the aqueous spectrum, like HE and YXH, they just contain a low amount of H2O (20%-30% probably) in the solution compared to KZE, HD, ZL (40%-50%), and especially compared to MBZ, MCZ, KZG, KZJ, HM, HN, HZ, (70%-75%), etc. H2O yields a much higher conductivity compared to organic liquid electrolyte, although a lower viscosity (and has a much poorer thermal coefficient in terms of capacitance and ESR). I attached a document by Chemi-con that describes the KY series as having "high water contains electrolyte" (or "high aqueous electrolyte") and LXZ as using "conventional electrolyte" (1-2% H2O content, probably using the organic solvent gamma butyrolactone and carboxylic acid as the solution or something similar since they moved away from the notorious quaternary ammonium salt system that caused leaking from the bungs in the 80s and 90s). Furthermore, United Chemi-con describe KY, KZE, KZG, and KZJ in their datasheets as using the same "unique low resistivity" electrolyte which suggests, coupled with the same temperature range (-40C to +105C) that they are all aqueous.

Disagree here.
Nichicon HM caps made after (and including) 2006 are fine. It's the ones between 2001 and 2004 that are *definitely* problematic. With 2005 ones, take out a coin, call heads or tails, and flip it - some have problems and others don't. Same goes for HN and HZ, especially when they sit on a shelf with no voltage applied.

I consider any capacitor that regularly bulges in storage without ever having bias applied to the plates or current passed through the solution to be very very bad. That suggests major chemistry issues unless they were overheated or exposed to incompatible cleaning agents. But then again, I don't expect highly aqueous 2,000 hour at 105*C capacitors to last very long under high heat conditions.

Those all look like good replacements for those KZGs, and they're all much more reliable than the KZG series.

[mitchmaster]

Re: Recapping a DFI nF4 Ultra-D

Thank you for your replies.

I have eventually replaced the caps and now the board is working fine, actually I'm using it right now to type this.

The capjob looks like crap though, my solder sucker is worse than I remembered so I didn't manage to clear many of the holes. In hindsight I should have spent 15€ and get one with a heated tip off Amazon... well maybe I'll fix it someday before retiring the board for good.

Thank you again for your help

[alindumitru46]

Re: Recapping a DFI nF4 Ultra-D

Hi, I read your post with big eyes. I own an Expert version of this motherboard, which now lights up only 3 of 4 LEDs, managing only a few starts.
On the board are three strongly oxidized areas that I tried to clean but not sure if it affects the mobo itself.
I'm thinking of doing a reccaping, but I encountered a strange resistance to latest attempts for desolder some of capacitors, and now I'm afraid to start (too cold pcb, too much Pb in the solder?!).
Effectively the solder is not melted enough to remove so easy the capacitors and release the holes. And I have used a 60W iron and a 150W big iron.
Now I have to think very well if they start such a job because DFI NF4 Ultra-Expert is very sensitive and crowded.

[Dan81]

Re: Recapping a DFI nF4 Ultra-D

Hi, I read your post with big eyes. I own an Expert version of this motherboard, which now lights up only 3 of 4 LEDs, managing only a few starts.
On the board are three strongly oxidized areas that I tried to clean but not sure if it affects the mobo itself.
I'm thinking of doing a reccaping, but I encountered a strange resistance to latest attempts for desolder some of capacitors, and now I'm afraid to start (too cold pcb, too much Pb in the solder?!).
Effectively the solder is not melted enough to remove so easy the capacitors and release the holes. And I have used a 60W iron and a 150W big iron.
Now I have to think very well if they start such a job because DFI NF4 Ultra-Expert is very sensitive and crowded.

Try using a gun shaped soldering iron that has a switchable wattage (my dead Kemot 30/130W one did).Those have a better heat transfer.

Oh,and if it helps,use some pliers and your soldering iron in case there's any pin left if a old cap breaks.

[momaka]

Re: Recapping a DFI nF4 Ultra-D

I'm thinking of doing a reccaping, but I encountered a strange resistance to latest attempts for desolder some of capacitors, and now I'm afraid to start (too cold pcb, too much Pb in the solder?!).
Effectively the solder is not melted enough to remove so easy the capacitors and release the holes. And I have used a 60W iron and a 150W big iron.

The 60W iron should be more than enough to remove caps from a motherboard.
What you need is flux - either liquid or gel. Standard Rosin or Rosin Mildly Activated (RMA) should both work well. Apply to joints, then hit them with your iron. Make sure your iron's tip has some solder on it as well. A medium-sized blob of solder on the tip will actually help quite a bit.

If unsure what I am talking about, create a new thread in the Equipment sub-forum and post some pictures of the irons you have.