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US source for capacitors

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leaknoil

Experienced Member
Joined
Aug 14, 2008
Messages
425
Location
Central California
I'm going to take the plunge an re-cap all my Z80 boxes power supplies. This means I need a mess of caps. Where's the cheap place to buy them and any quality differences I should be aware of in brands ? I don't want to ever do this again.
 
leaknoil said:
I'm going to take the plunge an re-cap all my Z80 boxes power supplies. This means I need a mess of caps. Where's the cheap place to buy them and any quality differences I should be aware of in brands ? I don't want to ever do this again.
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Stick with good brands--Nichicon, Sprague, Elna, Cornell-Dubilier, Panasonic, Illinois, etc. The problem with some otherwise fine brands such as Rubycon is that they're mercilessly faked by unscrupulous Chinese manufacturers. Stick with the 105C temps.

I can't venture as to where the cheapest ones might be-- some surplus dealers probably have pretty good deals.
 
Digikey, Mouser and PartsExpress are the three main suppliers I use. They each have their own caveats as far as minimum orders and shipping charges, so it depends entirely on what and how much you're ordering as to which place is cheaper.

Any of the brands carried by the above three suppliers would be fine, they don't carry any of the low-quality brands, nor have I ever gotten anything from them that I suspected to be fake.
 
Ah, forgot about Jameco. I'm not familiar with the other places, though.

older, better made-in-the-USA capacitors
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Ooh, that sends off all sorts of warning signals in my mind. How old are we talking? If they were produced more than about 10 years ago, I wouldn't touch 'em with a barge pole no matter how good a quality they were when new. Electrolytic capacitors have a limited life span, whether they're used or not.
 
Old Thrashbarg said:
Ooh, that sends off all sorts of warning signals in my mind. How old are we talking? If they were produced more than about 10 years ago, I wouldn't touch 'em with a barge pole no matter how good a quality they were when new. Electrolytic capacitors have a limited life span, whether they're used or not.
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It's worth asking. I'd put the upper limit on age closer to 15-20 years though, for NOS blue-jacket screw-terminal electrolytics. I've got some that are pushing 40 and are still doing fine.
 
I'd put the upper limit on age closer to 15-20 years though
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Yeah, they'll usually work fine for 15-20 years, sometimes more, but I was thinking within the bounds of "don't ever want to do this again". If you're going to repair something to keep in your collection, it probably wouldn't be the best idea to use parts that could potentially already be halfway through their normal usable life span. It'd be one thing using such parts to, say, repair leaky caps on a motherboard you're going to upgrade in a few years, but when you're thinking of the long term I'd be very much inclined to do everything I could to maximize the longevity of the repair.
 
Old Thrashbarg said:
Yeah, they'll usually work fine for 15-20 years, sometimes more, but I was thinking within the bounds of "don't ever want to do this again".
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Probably due to my age, my window of "Don't ever want to do this again" is a bit shorter. If the OP is in, say, his 20's or 30's, it may well be that there are no sources of caps that won't need replacing again before they wheel him off to the nursing home.

Just stay away from Chinese parts, if possible. Some of them seem to have a lifetime of a year or less. I suspect that a fair amount of consumer equipment is discarded because of bad Chinese caps.
 
One of the guys in the 68kmla forum replaced the metal electrolytic capacitors in old macs with Tantalum ones so they never "leak" again. While they won't leak, they do have a use lifespan and don't they tend to fail shorted (blowing up something important on the way out)?


I have recapped quite a few old mac compacts and mac IIs from the early 90's because of old leaking capacitors (using the same type). As long as they didn't eat anything the machines seem good to go and will probably outlast my interest in them (maybe).
 
One of the guys in the 68kmla forum replaced the metal electrolytic capacitors in old macs with Tantalum ones so they never "leak" again.
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Maybe look into the solid polymer caps, like many newer motherboards and such use. (Picture, if you're unfamiliar with them.) They're designed for longevity, and I haven't seen one fail that wasn't killed by some other problem (overvoltage, etc.). You'd probably have to stick with standard electrolytics for large values, but for smaller stuff, there's a decent variety and they're not all that expensive.
 
They probably won't do for the original application (filter caps in a linear PSU) unless you parallel a bunch of them. And the voltage ratings aren't high enough to use in the primary circuit of a SMPSU. Still, it's an interesting technology.

I'm getting used to the "bang" of old decoupling caps. I've never had one take any other components out--just occasionally trips the overload on the power supply. Power up again and it's as if nothing ever happened. Go back and replace them when you get "round tuit".

The humble disc ceramic is still a good choice for a decoupling cap. Polycarbonate or teflon caps are better, but they're pretty pricey.
 
Slightly o/t but..
I smoked yet another RIFA (!) filter cap this last weekend. Left my scope on to warm up sufficiently to do it's internal calibration, and became aware of that sickly sweet smell, fortunately there was a series resistor which burned out before it coated the inside of the machine's precision electronics with aluminium & carbon. My cheek starts to twitch when I see one now. (and unfortunately there are 2 in the terminal in front of me's power supply, (which I think is a badged Cifer T4, but as I can't find a picture of a t4 on the web, I'm not sure))
 
Ah yes, my scope was smoking RIFA not so long ago too. Scared the we-all-know-what out of me because it started sizzling and spitting as well. No damage done though, and the decidedly pungent residue came off easily enough with a dab of alcohol.

What really give me the heebie-jeebies are the six proper beer can-sized jobs in the 9-track tape drive I have in the basement. No idea how long since that thing's seen power, so I'll be checking them thoroughly and replacing any that seem even remotely questionable.
 
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