Dell Precision 490 Motherboard

[evilkitty]

I have some bulging caps here
3 KZJ 2200uf 6.3v, these are the gold caps http://www.paullinebarger.net/DS/Che...J%20series.pdf
i can not tell what the green ones are (edit: sanyo 1500uf 6.3V WF series https://www.badcaps.net/forum/attach...7&d=1313180606 )
Should i replace them with ones that can handle a higher voltage?

What should i replace them with?

[evilkitty]

I found a thread that suggested using the HN series to replace the KZJ series

another system has some bulging 6.3v WF 820uf and KZJ 1800uf 6.3v 8m diameter (seems to work still)

So i guess i can use these 2 part numbers: UHN1A222MPD and UHN0J182MPD6TD
but the 2200uf in discontinued and UHD or UHE series is recommended by Nichicon, so i guess i can use UHD0J222MPD

but what about the WF caps? i am guessing these are used for the ram based on there location
WF were supposed to be good caps, i guess the KZJ overworked them?
Would FR be a good replacement?

[evilkitty]

Maybe I should replace the Sanyo with these polymer caps:
https://www.mouser.com/ProductDetail...5MS158M1AAAE13 - 1500uf
https://www.mouser.com/ProductDetail...5KS827M1AAAE14 - 820uf
But, the ESR is bit lower
Stock Sanyo WF 1500uf has 18 mOhms and 2.2A Ripple VS 13 mOhms
Stock Sanyo WF 820uf has 21 mOhms and 1.3A Ripple VS 14 mOhms
Ripple is way higher on the polymer caps

While the numbers on Polymer caps looks great for these, but dat price... (Should I say screw it and get them?)
https://www.mouser.com/ProductDetail/667-EEU-FM0J222L - 2200uf
https://www.mouser.com/ProductDetail/647-UHN0J182MPD6TD - 1800uf
Stock UUC KZJ 2200uf has 11 VS 18 mOhms and 2.92A VS 2.47 Ripple
Stock UUC KZJ 1800uf has 12 VS 11 mOhms and 2.35A VS 2.22A Ripple

I could use this for the 2200uf cap: 9 mOhms and 3.19A Ripple
https://www.mouser.com/ProductDetail/647-UHN1A222MPD
but it is discontinued... is that a problem?
How close do i need to be to the stock ESR and Ripple?

[evilkitty]

I think I managed to find very close electrolytic caps

• 1500uf (Dell Precision 490):
  • Stock: Sanyo; WF; 10mm; 2.28A; 11 mOhm; 6.3V
  • Alt: Nichicon; HZ; 10mm; 2.28A; 9 mOhm; 6.3V
• 820uf (Dell Precision T3400):
  • Stock: Sanyo; WF; 8mm; 1.8A; 21 mOhm; 6.3V
  • Alt: UCC; KZN; 8mm; 1.6A; 18 mOhm; 10V
• 2200uf (Dell Precision 490):
  • Stock: UCC; KZJ; 10mm; 2.92A; 11 mOhm; 6.3V
  • Alt: Nichicon; HN; 10mm; 3.19A; 9 mOhm; 10V
• 1800uf (Dell Precision T3400):
  • Stock: UCC; KZJ; 8mm; 2.35A; 12 mOhm; 6.3V
  • Alt: UCC; HN; 8mm; 2.22A; 11 mOhm; 6.3V

Do those look like good replacements?

With the WF caps I am only changing the bulging ones (all 3 in the 490 and 2 of 6 in the T3400)
With the ZKJ caps I am replacing all of them, bulging or not (6 in the 490 and 7 in the T3400)

[Per Hansson]

Ones in your last post look excellent.
I'd also look into the cooling for those FB-DIMM's
They run very toasty so might be what killed those Sanyo caps...

[Wester547]

Sanyo’s (Suncon) WF series is failure prone, especially whilst under thermal duress. It’s debatable that heat killed them, but KZJ is a known dud series too and have also failed in these toasty machines. FWIW, those Precision 490 (and 690) boards use MCZ, KZJ, and WF interchangeably in the position that those 1500µF 6.3V caps are in, and thus far I’ve only seen WF and KZJ go bad there. Those T3400 machines (and all Dell motherboards that have a similar layout) also use KZG, KZJ, MCZ, HM (post-2004 datecodes), FL, and WF interchangeably for the 820µF 6.3V caps, and I’ve only seen WF and KZG bulge so far (haven’t seen a 820µF 6.3V KZJ bulge anywhere but in a USFF Dell, but I’ve seen quite a few of them go high ESR with no signs - the larger diameter and/or taller 6.3V KZJs OTOH are more prone to bulging).

Your replacements look good.

[evilkitty]

Thanks, should I replace all 6 in the t3400?, only 2 are slightly bulging and the system still works
I do not really care much about the t3400 (it is only 2$ but i am a tight a$$)
Are the WF caps known to fail without bulging?

[Wester547]

If two of the six have bulged, the other four may not be far behind. Any capacitor can fail without symptoms, so preemptive replacement is sound.

[momaka]

Replace all the Sanyo WF caps. Otherwise, they might (very likely) come back and bite ya again.

These Dell workstation PCs are excellent otherwise and worth every $ you invest in them (IMO).

[evilkitty]

Thanks caps have been ordered, sadly one is on back order... better that not on order and out of stock, hopefully i can to get them installed on/by may 13/12th
hopefully that is the only thing wrong with the 490 and there is not some bad smt cap or something