Rubycon 400v 6.8uf Cap. Not in DS?

[chozo4]

Had to repair a 12v 500mA switching power supply for a linksys router I use on the go. It was overheating to the point of thermal shutoff (due to the ST VIPer voltage IC on it) while even idle. The insides were smoothed and looked to have been slightly melted from the heat as expected. After inspection I found it had bulging 400v 6.8uf & 16v 220uf Samxon caps with the wrapping so dried out it was cracking off. Was no help there was so much glue in there the insides should have just been molded to a box which didn't help with heat in any form.

Being as I needed caps on the fly as I'll be traveling overseas where the voltage is 220v@50hz for my router... I had to resort to ebay. Most I had in my cap box were up to 200v-250v and didn't want to cut it that close.

Ended up with buying the closest match I could get [at the time] on ebay which I normally don't buy caps from to begin with. They happened to be legit looking Rubycons but cannot find the matching capacity or size in their YXA datasheet at all.

Brand: Rubycon
Series: YXA
Voltage: 400v
Capacity: 6.8uf
Height: 16mm
Diameter: 8mm

Knowing how everyone is a voyeur here is the image of them from the listing.


I'll get a picture of the failed caps later on however once my batteries recharge3 for my crapcam. The DC side 16v 220uf Samxon caps wI replaced with a pair of 16v/100uf OS-Cons salvaged from a dead Gigabyte motherboard since the high ripple will be more than sufficient to make up for the lower capacitance. It works fine but those 400v Rubycons I find are questionable due to not being listed in their Datasheets.

[lexwalker]

Re: Rubycon 400v 6.8uf Cap. Not in DS?

Had to repair a 12v 500mA switching power supply for a linksys router I use on the go. It was overheating to the point of thermal shutoff (due to the ST VIPer voltage IC on it) while even idle. The insides were smoothed and looked to have been slightly melted from the heat as expected. After inspection I found it had bulging 400v 6.8uf & 16v 220uf Samxon caps with the wrapping so dried out it was cracking off. Was no help there was so much glue in there the insides should have just been molded to a box which didn't help with heat in any form.

Being as I needed caps on the fly as I'll be traveling overseas where the voltage is 220v@50hz for my router... I had to resort to ebay. Most I had in my cap box were up to 200v-250v and didn't want to cut it that close.

Ended up with buying the closest match I could get [at the time] on ebay which I normally don't buy caps from to begin with. They happened to be legit looking Rubycons but cannot find the matching capacity or size in their YXA datasheet at all.

Brand: Rubycon
Series: YXA
Voltage: 400v
Capacity: 6.8uf
Height: 16mm
Diameter: 8mm

Knowing how everyone is a voyeur here is the image of them from the listing.

You should know better, as on eBay there are plenty of counterfeit Rubycon, Nichicon, Panasonic, Nippon Chemi-con (a.k.a United Chemi-con), Elna and Sanyo capacitors on sale. Some counterfeits are easy to spot, especially by looking at the printing on the sleeve, color of the markings, the vent on the top and/or the bung at the bottom. Some counterfeits can look pretty darn close to the originals and quite often does not show up in the datasheet for the given capacitance and voltage rating, and sometimes it can be found in the datasheet but of the wrong size (usually the height).

I would recommend getting capacitors from authorised electronic components distributor such as Newark/Farnell/element14, RS Components/Allied Electronics, Mouser and Digikey. At least they are guranteed to be genuine...

Examples: Newark > Passive Components > Capacitors > Aluminium Electrolytic Capacitors - Leaded > 400BXC6R8MEFC10X16, Allied Electronics > Passive Components > Capacitors > ULD2G6R8MPD1TD, Mouser > Passive Components > Capacitors > Aluminum Electrolytic Capacitors > Aluminum Electrolytic Capacitors - Leaded > Nichicon UCS2W6R8MPD, Digikey > Capacitors > Aluminum Capacitors > EKXG401ELL6R8MJ16S, etc...

I'll get a picture of the failed caps later on however once my batteries recharge3 for my crapcam. The DC side 16v 220uf Samxon caps wI replaced with a pair of 16v/100uf OS-Cons salvaged from a dead Gigabyte motherboard since the high ripple will be more than sufficient to make up for the lower capacitance. It works fine but those 400v Rubycons I find are questionable due to not being listed in their Datasheets.

Does not sound right, as that is a huge capacitance difference (at least half of the original capacitance is gone). You should be using 220uF instead of 100uF...

[chozo4]

Re: Rubycon 400v 6.8uf Cap. Not in DS?

Yeah, I know better for sure about buying caps from eBay but I needed them in a pinch and figured at the current point anything was better than nothing at the moment. I was about to update the post accordingly to correct that part about the 100uf Oscons as I'd managed to scrounge up a pair of 16v 270uf Oscons earlier to replace them with instead and get the capacitance on par.

The irony is, I had just made out an order from mouser beforehand and didn't want to pay another $5 shipping for just 2 capacitors as I usually don't get large batches. Get what you pay for really - but the seller was selling them as old stock (*shrug* 28th week of 2010 based on the datecode) and was in New York so figured unlikely to be chinese knockoffs which made me figure 'ah what the hell'. I needed that slap to reality there honestly.

I tend to fit in the category of 'long as it works for the short term until I get the rest I'm good' providing it's for a short term use and not functioning out of the ordinary afterward such as heat output that shouldn't be.

I'll end up buying a proper pair from mouser afterall as a precautionary measure and peace of mind at this point. Figure something else will come to mind while looking about to make up for the shipping difference.

Thanks Lex.

[lexwalker]

Re: Rubycon 400v 6.8uf Cap. Not in DS?

Yeah, I know better for sure about buying caps from eBay but I needed them in a pinch and figured at the current point anything was better than nothing at the moment. I was about to update the post accordingly to correct that part about the 100uf Oscons as I'd managed to scrounge up a pair of 16v 270uf Oscons earlier to replace them with instead and get the capacitance on par.

The irony is, I had just made out an order from mouser beforehand and didn't want to pay another $5 shipping for just 2 capacitors as I usually don't get large batches. Get what you pay for really - but the seller was selling them as old stock (*shrug* 28th week of 2010 based on the datecode) and was in New York so figured unlikely to be chinese knockoffs which made me figure 'ah what the hell'. I needed that slap to reality there honestly.

Counterfeit capacitors are pretty much the norm in eBay. Some local shops here also sells counterfeit capacitors, though they were easy to detect (always wrong colors, wrong size and incorrect bung). Heck, I've even found some on motherboards from a major manufacturer! Those were Rubycons also...errrmm... or Rubvcons? The "y" looks suspicious (more like an elongated "v") and does not look anything like the "y" on my ancient Rubycons or the current Rubycons in my stock.

I tend to fit in the category of 'long as it works for the short term until I get the rest I'm good' providing it's for a short term use and not functioning out of the ordinary afterward such as heat output that shouldn't be.

I'll end up buying a proper pair from mouser afterall as a precautionary measure and peace of mind at this point. Figure something else will come to mind while looking about to make up for the shipping difference.

Thanks Lex.

Over here, I've used both element14 and RS Components as they do not impose any shipping fees (free delivery). Majority of stuff from RS Components are in bulk (of at least 5 to 10 units/pieces per order) though some more expensive ones can be ordered as a single unit/piece. And yes, Mouser usually has shipping fees...

[chozo4]

Re: Rubycon 400v 6.8uf Cap. Not in DS?

Over here, I've used both element14 and RS Components as they do not impose any shipping fees (free delivery). Majority of stuff from RS Components are in bulk (of at least 5 to 10 units/pieces per order) though some more expensive ones can be ordered as a single unit/piece. And yes, Mouser usually has shipping fees...

Ah goodie, I've actually never heard of Element14 until you'd mentioned it now. I'll definitely have to look into it because of the free shipping and take a gander at their stock.

[linuxguru]

Re: Rubycon 400v 6.8uf Cap. Not in DS?

IMHO, those Rubycon YXA 6.8uF/400V that you got from EBay are 100% original NOS caps. They'll work practically forever on the primary side of the small SMPS wall-warts. There are however larger values available in slight larger diameters - 22 or 47uF/400V in Nichicon CS, PW, etc. are in the 16 or 18mm diameter range, and fairly compact in height.

Edit: All the Japanese majors have capacitors that differ in dimensions from the preferred dimensions on the datasheet. The alternate dimensions may be special-production items for large customers, or just older or newer product that was removed or not updated on the datasheet.

[stj]

Re: Rubycon 400v 6.8uf Cap. Not in DS?

i would have just gone to a street market and picked up a 1a or 2a 12v psu for a couple of Euro.

it's hardly worth spending money to fix a 500ma psu - specially as most routers want 1a minimum.
which may explain why it got so hot!!!

[chozo4]

Re: Rubycon 400v 6.8uf Cap. Not in DS?

IMHO, those Rubycon YXA 6.8uF/400V that you got from EBay are 100% original NOS caps. They'll work practically forever on the primary side of the small SMPS wall-warts. There are however larger values available in slight larger diameters - 22 or 47uF/400V in Nichicon CS, PW, etc. are in the 16 or 18mm diameter range, and fairly compact in height.

Edit: All the Japanese majors have capacitors that differ in dimensions from the preferred dimensions on the datasheet. The alternate dimensions may be special-production items for large customers, or just older or newer product that was removed or not updated on the datasheet.

That helps as I normally go by Datasheets verbatim as being the only offerings. I guess I don't need to worry so much after all then about them if that's the case.

i would have just gone to a street market and picked up a 1a or 2a 12v psu for a couple of Euro.

it's hardly worth spending money to fix a 500ma psu - specially as most routers want 1a minimum.
which may explain why it got so hot!!!

It actually got so hot (thermal shutoff when not connected to anything in less than 5 minutes) due to the caps failing inside (Samxon GF/KM) series. It got to the point the KM's even had their sleeves brittle and flaking off from touch. Ever since the recap it's been cool to the touch while pushing it on an overclocked WRT54G-TM (which is also my webserver) during stress testing but the router only consumes around 4-5watts (~400ma) as it is so well within limits. It's a thin wart which was preferable and hate to toss something that can be fixed. I wish those were so cheap to get here however. I have plenty of linear transformer based warts so I have many I could use.. just needed a switcher for when I go overseas.

Can tell how much it overheated previously as the board was even darkened as a result. I did remove about 90% of the glue they used in it as even the original caps were at least 50% submerged in it. Was a bit ridiculous looking like someone just squirted the whole bottle blindly.

[lexwalker]

Re: Rubycon 400v 6.8uf Cap. Not in DS?

Ah goodie, I've actually never heard of Element14 until you'd mentioned it now. I'll definitely have to look into it because of the free shipping and take a gander at their stock.

Check and inquire their hotline for any possible delivery charges. May differ from country to country. On my side, all web orders are given free delivery...

Anyway, here's that questionable Rubycon with that suspicious "y" in the first attached image. Its also a YXA series. None of my Rubycons have that type of "y" printing. In the second image, fake Nichicon PW series capacitor (from someone else's self-repair). The colors and the size are both wrong. When pulled off the board, the bung is incorrect. The real Nichicon PW series have white letters on brown (while the fake one is silver on black), plus the size is supposed to 12.5x20mm for 1000uF 25VDC (while the fake one is 10x20mm).

[linuxguru]

Re: Rubycon 400v 6.8uf Cap. Not in DS?

Those Samxons don't look too bad - maybe slightly bulged and dried out. The excess heat may be due to a leaky snubber diode - possibly D1. If it's not heating up now, you can leave it alone, but otherwise it may be worth replacing D1 with a UF4007 or HER108 fast-recovery rectifier.

Edit: The Nichicon PW above is most probably fake, but that Rubycon YXA is probably authentic (need a closer look at the bung, vent pattern, scoring and text to be sure). YXA isn't worth faking, since it's a widely available GP/moderate ESR series.

[ben7]

Re: Rubycon 400v 6.8uf Cap. Not in DS?

Check and inquire their hotline for any possible delivery charges. May differ from country to country. On my side, all web orders are given free delivery...

Anyway, here's that questionable Rubycon with that suspicious "y" in the first attached image. Its also a YXA series. None of my Rubycons have that type of "y" printing. In the second image, fake Nichicon PW series capacitor (from someone else's self-repair). The colors and the size are both wrong. When pulled off the board, the bung is incorrect. The real Nichicon PW series have white letters on brown (while the fake one is silver on black), plus the size is supposed to 12.5x20mm for 1000uF 25VDC (while the fake one is 10x20mm).

I have a switching bench PSU that has fake Nichicon PW's also. They are black, instead of the proper brown color, and the printing is horrible/messy, AND the bung is circular, AAAND the size is incorrect!...

Those Samxons don't look too bad - maybe slightly bulged and dried out. The excess heat may be due to a leaky snubber diode - possibly D1. If it's not heating up now, you can leave it alone, but otherwise it may be worth replacing D1 with a UF4007 or HER108 fast-recovery rectifier.

Edit: The Nichicon PW above is most probably fake, but that Rubycon YXA is probably authentic (need a closer look at the bung, vent pattern, scoring and text to be sure). YXA isn't worth faking, since it's a widely available GP/moderate ESR series.

I've seen cases where the bad caps cause an instability in the PSU's feedback, when the caps fail the poles and zeros (math) change, and the PSU goes into some sub-harmonic oscillation, which makes it inefficient.... in some cases, very inefficient.

[chozo4]

Re: Rubycon 400v 6.8uf Cap. Not in DS?

Those Samxons don't look too bad - maybe slightly bulged and dried out. The excess heat may be due to a leaky snubber diode - possibly D1. If it's not heating up now, you can leave it alone, but otherwise it may be worth replacing D1 with a UF4007 or HER108 fast-recovery rectifier.

Edit: The Nichicon PW above is most probably fake, but that Rubycon YXA is probably authentic (need a closer look at the bung, vent pattern, scoring and text to be sure). YXA isn't worth faking, since it's a widely available GP/moderate ESR series.

One of the GF's failed despite showing no physical changes as well. Before changing both the supply would audibly click and struggle to provide even so much as 5v despite changing the primary filter caps out. If I'm going to recap one I'd be better off recapping them all.

I'll look into the diode and run it through a few paces off board this week for the heck of it. I don't have any axial diodes extra aside from the common N and U series ones. Seems to be all there are on the scrap boards I have from a destroyed projection TV I salvaged them from as someone smashed the Fresnel lens, clipped out the copper windings/inductors, etc.

Visually, I cannot really tell the difference with that YXA from the photos. It otherwise looks okay aside from the compressed Y on the inner bell curve of the cap.