are axial caps from the 90's any better then radial ones? - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: April 20, 2025, 09:46:18 pm
content: If you are replacing caps in something that is from the 90's where there is bad capacitor concerns, are axial caps also prone to leaking?

author: incf
author_rank: Frequent Contributor
timestamp: April 20, 2025, 09:52:33 pm
content: The following is speculation: it's not the package that matters (the package does not normally influence the mechanism by which most 90's capacitors die), it's the electrolyte that causes the failure. And who can really say with confidence which batches of electrolyte were good or bad - or what capacitors use which electrolyte formulation.

author: Xena E
author_rank: Frequent Contributor
timestamp: April 20, 2025, 10:23:07 pm
content: Yes axial electrolytic caps do leak, but do they leak more than radial, the clever answer could be only half as likely, given similar quality of construction as generally they only have one lead to seal, whereas the radial has two!Radial caps IMO are better operationally than axial as the connectioncanbe made between board traces and active part of the capacitor, closer than with an axial: with that in mind replacing an axial with a radial, by the shear length of lead necessary the radial probably will be operationally worse because of it!A personal hobby horse of mine is the sitting of radial caps directly on the board with no pad between as a strain relief and further leakage barrier.May seem a self contradictory post, but hopefully food for thought. Just pick from what's most important for your application.X

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: April 21, 2025, 03:23:19 am
content: IMHO, cap manufacturers put their best efforts into radial caps. Look at all the specialized series offered. They never put that much effort into axial caps, mostly standard 85C commercial grade parts. No low leakage, low ESR, high temperature, sub-miniature, etc. Radials mostly took over the market and pushed axials out. In terms of physical leakage, I haven't noticed much difference as properly made parts both go 50 years with little trouble if applied correctly. An exception would be low voltage high value parts like 500 uF 6V. Those don't seem to hold up well.

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: April 21, 2025, 07:43:22 pm
content: Some of the first failures of this "leakage problem" was with axial capacitors.Jeff

author: oz2cpu
author_rank: Frequent Contributor
timestamp: April 22, 2025, 08:03:09 am
content: i repair vintage equipment all the time,most old stuff axial caps where more common,so today they are old and leaky just as well as a radial will be 40-50 years later,not much happened in the rubber seal, metal outher bend into the seal,it is the same design more or less.if we only talk about leak issues, one could argue where is the leak comming from ?the pins ?the radial type got two rubber sealed pins, while axial type got only one rubber sealed pin, so double chance of a leak.I have seen equipment with 10 different types of caps, only one type leaked, but ALL of them leaked that type !!no matter where it was locaked inside the ultra huge unit, so it is not only about temperature ripple current and such,manufacture quality, materials used and just age is also a thing.