New Capacitor Brands, Good or Bad?

[Behemot]

Re: New Capacitor Brands, Good or Bad?

Think the polarity is fine but there may actually be higher voltage. Don't know, gonna check next time when the board'll be outta the case It's working OK so far even with mild overclock (Prescott 3@3,3 GHz).

[momaka]

Re: New Capacitor Brands, Good or Bad?

Lol the fact it has boom in its name is a straight up no go

Yes, I agree with that 100%.
Same goes if it has "Pow" in the name. Like PowMax... or PoWork (anyone remember that JonnyGuru basement roundup article? )

Is Wurth OK?

Well, I don't have any experience with them to say. But the fact that Digikey and Farnell carry them suggests to me that they are at least somewhat okay. And like stj said, their polymers are probably alright, but the electrolytics, I just can't say anything about them.

Old Japanese stuff is generally chock-full of general purpose capacitors and they are rarely bad in my experience even at 30+ years old.

Yup. Many tube TVs made in the 80's and 90's are still functional today, provided they haven't been discarded already. I'm still rocking my CRT monitors daily here.

The cap I had in mind was a Sprague 30D series part made in 1977. I've seen parts in recently used equipment that had date codes in the early 1970s and late 1960s.

Interesting you mentioned those. I have an HP 6291A DC power supply that I found discarded. It has quite a few Sprague 30D caps. And like you noted, quite a few actually read good spec on my cheap TT/ESR meter. However, I replaced some of the big caps from that power supply, because it wasn't working and I was fearing that if something went wrong, these caps have no vents (as far as I can see). So I thought that could be a hazard. The one cap I am most afraid of is a big metal can General Electric rated for 1500 uF and 40 WV. That cap is quite big and made of thick aluminum, yet has no vent anywhere I can see. Explosive hazard???

Damn, two of my Rubycon MBZ caps on the PC board I write from are venting again. Wonder if I used wrong voltage or what, think they are the same as I have already replaced twice!

The only thing I can think of is if you put 6.3V or 10V caps on the 12V rail. Probably 10V caps, as 6.3V caps can only handle a maximum surge voltage of around 8V and should bulge rather quickly. 10V caps, on the other hand, can handle around 13V peak, I think.

But if you got 6.3V or 10V caps on a 3.3V or 5V rail, and they are bulging because of overvoltage, I think you have bigger problems. Like, PSU going ballistic very soon (but I doubt that, as I know you know your PSUs).

[Behemot]

Re: New Capacitor Brands, Good or Bad?

Yeah there may be +12 V there…won't know for certain untill I remove it again. BTW the PSU gets pretty hot even with the case opened, no wonder the small transistor base caps (2.2 uF IIRC) died recently on me. Guess I should really cut some hole in the upper part and add two fans as usually. Its the old case where the PSU is mounted in vertical position…

[Behemot]

Re: New Capacitor Brands, Good or Bad?

Just found some new crap brand inside a russian Powerman UPS. Its y.u.g. inside an oval. No series marking but I assume it's general purpose as all the others. They don't put anything else in UPSes anyway…

This UPS is just incredible…they saved on the fuses and soldered accumulator cables directly onto the board…not even through the holes, they put it to the solder side. If something goes bad or overloads, the transistors will explode like a grenade. The fuses ussually survive, but at least you know they are there if everything else fails. Not here. Guess they use die bonding inside the FETs packages as fuses

[momaka]

Re: New Capacitor Brands, Good or Bad?

This UPS is just incredible…they saved on the fuses and soldered accumulator cables directly onto the board…not even through the holes, they put it to the solder side. If something goes bad or overloads, the transistors will explode like a grenade. The fuses ussually survive, but at least you know they are there if everything else fails. Not here. Guess they use die bonding inside the FETs packages as fuses

What do you expect? This is Russian hardware. Russians are some of the toughest people on earth - they don't need no stinkin' safety! The savings from not putting a fuse were probably spent towards buying Vodka or other liquor.

[RJARRRPCGP]

Re: New Capacitor Brands, Good or Bad?

"AxBoom"!

Sounds more like a Halo gamer tag...

[PeteS in CA]

Re: New Capacitor Brands, Good or Bad?

Interesting you mentioned those. I have an HP 6291A DC power supply that I found discarded. It has quite a few Sprague 30D caps. And like you noted, quite a few actually read good spec on my cheap TT/ESR meter. However, I replaced some of the big caps from that power supply, because it wasn't working and I was fearing that if something went wrong, these caps have no vents (as far as I can see). So I thought that could be a hazard. The one cap I am most afraid of is a big metal can General Electric rated for 1500 uF and 40 WV. That cap is quite big and made of thick aluminum, yet has no vent anywhere I can see. Explosive hazard???

The late 60s and early 70s parts were in an ancient Harris/HP lab power supply. I think the 30YO 30D cap was in a Sorensen lab supply.

If that 1500uF, 40V GE 'lytic is a screw terminal type, it might have a vent on the end with the terminals. It might look like a little round rubber plug. Some larger PCB mount through-hole parts had vent scorings that were hidden by a plastic disk that was under and held in place by the shrink sleeve.

If the GE 'lytic really has no provision for a vent, I'd be worried about the thing launching if it failed, though pressure could also rip open the weakest point in the can. I don't think the can would burst, releasing shrapnel. Personally, if there really is no vent I would replace it (I'd be tempted to replace it anyway, since I've seen a cap that did have a vent launch, due pressure building up so fast that the vent couldn't open quickly enough (using a 7.5V cap in a 48V circuit could have that effect, IYKWIM).

[kc8adu]

Re: New Capacitor Brands, Good or Bad?

i recently saw a site offering yec caps.
these were junk all through the 80's-90's
uniden loved these and the product failures showed this.
just had my bench littered with them resurrecting a friends uniden/president hr2600 10m rig.must have been 35+ of them.rig back on the air every night in out local 10m gang.
as for new brands they are likely SOSDD.
same old shit different day(name)

[momaka]

Re: New Capacitor Brands, Good or Bad?

i recently saw a site offering yec caps.

Lol, that's sad. I call those YEC caps YUCK!
And HEC caps... ah, what the HECK!

as for new brands they are likely SOSDD.
same old shit different day(name)

Agreed.
Anything I find with an obscure name immediately joins that list.

If that 1500uF, 40V GE 'lytic is a screw terminal type, it might have a vent on the end with the terminals. It might look like a little round rubber plug. Some larger PCB mount through-hole parts had vent scorings that were hidden by a plastic disk that was under and held in place by the shrink sleeve.

It's a PCB-mount through-hole cap with only a clear sleeve on top. The marks are actually stamped onto the can and visible through the clear sleeve. There is not vent on the bottom - only what looks like a PCB (that I assume is enforcing a rubber bung underneath it from pushing out). No vent on top either. The cap looks a tiny bit bulged where the stamped marks are on the side of the can. I think if it blows, it will probably rupture there. Still, that looks rather unsafe to me. I've heard of stories of these old caps building enough pressure to grenade and destroy the equipment they were in. IIRC, I think it was either goontron here (or perhaps eccerr0r... or perhaps someone else) that said they had one rupture and throw some shrapnel and cut their arm.

... I've seen a cap that did have a vent launch, due pressure building up so fast that the vent couldn't open quickly enough (using a 7.5V cap in a 48V circuit could have that effect, IYKWIM).

Luckily, not in my case. I already checked the circuit, and it tops out at 32V for the spot where that 40V cap was. A bit close, but probably alright. It's from a line transformer tap, so unless I plug the power supply in the wrong line voltage (like, 230 VAC, for example), then it should be safe.