SOLVED Need new caps.

[don256us]

While this is for a motherboard, it's for a Cisco Catalyst 3560 PoE-24. Don't let that deter you from this thread though. These are *very* common in the computer industry. A quick search of eBay confirms that all brands of computer motherboards use these exact parts.

I need to replace five 1800uf 6.3 volt capacitors.

The question? Well, while I only paid $30 for this switch as a learning aid, I'd like to make sure that I'm getting good parts to replace the bad ones.

What should I be looking for in a capacitor? Brand, source, material, etc.? I know that some of you are real electronics types who can school me good so whatever you got I'll take.

Thanks.

 

[Alaric]

The best would be Japanese and rated for 105C. Nichicon comes to mind first. Something like this https://www.mouser.com/productdetai...GAEpiMZZMukHu%2bjC5l7Yd65PJRB7gnpW7JYZYBjODY=

Panasonic is good, too. I try to avoid the Chinese capacitors for anything important or hard to get to.

 

[Mandrake4565]

Digikey has always been my go to for Caps. I agree with Alaric, go Panisonic or Nichicon. Just make sure when you purchase the caps you get the same lead spacing as the caps you're replacing.

 

[don256us]

Thanks for the lead spacing tip and the brand(s). What about impedance and ripple currents? High or low numbers better?

 

[WhitehawkEQ]

Thanks for the lead spacing tip and the brand(s). What about impedance and ripple currents? High or low numbers better?

I agree with Mandrake and Alaric but also make sure you get the same voltage, capacitance value and size as well, as for impedance, get caps with low ESR.

 

[Tech Tweaker]

I generally go with Nippon Chemicon/United Chemicon or Rubycon, though I think I've also bought Panasonic caps before. I've always had good luck buying from Digikey, usually getting delivery of my order within one to three business days.

 

[Alaric]

I almost forgot one more item. Get the tightest tolerances you can. Some caps are +/- 20%, some are +/- 5%. If these are the caps next to the socket/VRMs (I suspect so from the specs) tighter tolerances across all of them will result in more stable power delivery. The 105C temp rating is a must for me, too, especially in that environment.

 

[don256us]

Every single cap out there with 1800uf and 6.3v are +/- 20%. Looking at digikey they are all at 20%.

I'll look for the 105c and low ESR as my deciding factors, then double check the brand before I buy.

 

[don256us]

This is what I am replacing. Four are bulged and there are five in total. I'll replace them all naturally.

 

[Alaric]

I didn't think about the +/- 5% caps being easier to find for audio gear. Mouser is also a good source for caps https://www.mouser.com/Passive-Comp...0z7l5&Keyword=electrolytic+capacitors&FS=True

 

[pqwoerituytruei]

Panasonic, Nichicon, United Chemi-Con (UCC), and Rubycon are good brand names
Panasonic's low ESR caps (FC, FK, FM, FR, & FS series) are commonly recommended on the badcaps forum

High ripple current = good
Low ESR = good

given these caps are bulging either they got too hot or a higher voltage rated cap should have been used
if you can find a 1800uf cap that is rated for say 16v that will fit, you probably will need to replace it for a VERY VERY long time

I do not know if this will fit, but this cap will probably do a good job (not sure what series your stock bulging cap is to compare)
https://www.mouser.com/productdetail/EEU-FS1C182B

 

[Alaric]

You have some wiggle room on capacitance, NOT voltage. Send a 16v surge through a 6.3 volt system and Bad Things will ensue.

 

[pqwoerituytruei]

a cap is not a voltage regulator (or a step-up transformer), a cap will not store voltage over what it is given at a peak value, if peak voltage is greater than the cap's rated value the cap will have a short life span (pre-mature death)

The voltage rating is the caps limit, a limit is not to be exceeded

 

[WhitehawkEQ]

Here is some good reading on how caps work
How Capacitors Work

 

[Dr. McCoy]

Speaking of caps I bought myself a 200 count bag of 6.3v 3300uf Sanyo's last year that's done well, was using these for fixing things Socket A related for the most part since these caps are common to those boards. Fixed a quad of AN7's I had for a long time and a couple of DFI Infinity's I picked up during that time cheap because they had problems, all cap related. I found them on fleabay and naturally picked them up because the price per cap was dirt cheap compared to what I could have found in other listings. Since there was 200 of these the actual price to get them was high for what I was trying to do but simply to have these for future jobs was the frame of mind I went with.
It will be years before I'll have to worry about being short on these again so in actuality was well worth it.

Rubicon's are what I would have preferred but these are fine, no problems with them so far. 6.3v 1800uf caps should be easy to find since those are a common cap type.

The ones I seem to have a hard time coming up with are the 10v caps DFI's used with many of their boards but even those can be found.

 

[don256us]

Are you guys saying that I could use a 1800uf *16v* cap in place of my 1800uf *6.3v* original? If that's true, then I have the 16v caps on hand.

 

[Lochekey]

I buy caps off of amazon a lot as I can get small quantities cheaper sometimes. I use the other sites to look up part numbers and then cross reference to amazon. Does not always work but it is another place to check.

 

[pqwoerituytruei]

Are you guys saying that I could use a 1800uf *16v* cap in place of my 1800uf *6.3v* original? If that's true, then I have the 16v caps on hand.

yes, a replacement caps voltage rating can be the same or higher (don't mix up AC/DC voltage ratings), you just have to watch the diameter, lead spacing, and height so as long as it will fit on the board and in the case you are good, just do not put the cap on leads to make it fit some place else
you still need to compare this on hand cap's ripple/esr to the stock cap to be sure it will work properly for your needs

capacitance values can vary within reason, but if the cap is being used as a RC timer or is for audio you need to be as precise as possible on mating it (watch the tolerance)

 

[Dr. McCoy]

I buy caps off of amazon a lot as I can get small quantities cheaper sometimes. I use the other sites to look up part numbers and then cross reference to amazon. Does not always work but it is another place to check.

Normally I look at the price per cap in a listing before buying, I tend to buy more than needed at any given time since I know I'll probrably need them again at some point - That's just me but I do that.
Getting a good brandname and checking the overall cost per cap is the basics of it all. Also don't forget to figure in the shipping cost, some will try to jack up the price with that.

 

[pqwoerituytruei]

exercise caution when getting caps from a non-qualified vender, you do not want counterfeit caps:
https://www.eevblog.com/forum/projects/warning-fake-large-electrolytic-on-ebay-!!/