How to spot a counterfeit Capacitor — #10

Post #10 by uniserver

Source Forum	68kMLA
Category	Troubleshooting
Post Date	Sun, 12 Oct 2014 - 21:42
Original URL	https://68kmla.org/bb/threads/how-to-spot-a-counterfeit-capacitor.371/

Post

Yeah max, i think if you were to order cheap caps from china, I think the best thing would be to buy their brand.

If its a name brand and its cheap, then its probably counterfit. I would like to say that making an electrolytic cap is probably not rocket sicence.

for instance.

http://www.bdent.com/catalogsearch/result/?q=2200uf+25v

these guys are selling SunCon. also Lots of the others too.

And Mouser has been selling these EPCOS caps. In some situations they are the lowest price

i looked them up and come to find out TDK had just bought them.

i really like TDK's MLCC Ceramic caps.

So I bought a reel of 1000 47uf/16v/6.3x5.4mm SMD last spring

haven't really used much of them though, because i am have been offering free SMT Ceramic caps

for the stock price.

I would like to try some of the Chinese branded caps, just to see, out of interest if they are up to standard.

but don't really have the time to mess around right now.

for instance:

http://www.aliexpress.com/item/25V-2200uF-Electrolytic-capacitors-new-products-and-ROHS/451172965.html

QIFA? lol

http://www.aliexpress.com/item/Free-shipping-30pcs-lot-2200uF-25V-105-Radial-Electrolytic-Capacitor-13-20mm/763842486.html?s=p

Sold By
Shenzhen Jusunsung Electronic Co., Ltd.
China (Mainland) (Guangdong)

http://www.aliexpress.com/item/25V-2200UF-2200UF-25V-DIP2-13-20MM-place-of-production-made-in-china/1810363550.html

CHENXENG?

http://www.aliexpress.com/item/Free-shipping-200pcs-lot-2200uf-25V-13-20/1953478792.html

UNITE?

it would be nice to have some input on these things… i would like to set up a durability test bench … and wire them up and

put them through some extreme testing.

Elffin:

What i noticed was the ELNA ( LONG LIFE ) caps as the ones always leaking, at least in the TDK PSU's

but james is right when he said this:

https://68kmla.org/forums/index.php?/topic/18815-caps-lc-tdk-power-supply-fix-for-pizza-box-macs/

James1095

All of the caps in several of mine were Nichicon, and the same ones were still bad. Even those that weren't leaking tested bad with the ESR meter. Nichicon is a quality part, the fault lies in the conditions in the power supply. Switching PSUs are notoriously hard on output capacitors, and these are extremely compact units that place the caps in close proximity to other parts that get hot.

For whatever reason, ESR tends to drop as you heat up an electrolytic capacitor, so that's why the heater trick works. It's also why a classic symptom of failing capacitors is equipment that's cranky when cold but smooths out a bit as it warms up. Of course heating the capacitors also accelerates their demise, but at this point they're already shot anyway.