- Replacing Large Electrolytics - 3 Updates
| John-Del <ohger1s@gmail.com>: Aug 25 10:39AM -0700 On Saturday, August 25, 2018 at 9:32:35 AM UTC-4, Cursitor Doom wrote: > Fortunately I'm not doing this for any customer; I'm only a hobbyist > working on my own stuff, so can easily afford to be proven wrong in this > if such should turn out to be the case. ;-) Heat and charge cycles do affect a capacitor's life, but they're not the only factors. Humans who smoke, drink, and do drugs have a shorter life than those who don't, but we all will die eventually. I've had plenty of electros in stock go off value, become leaky, and go up in ESR just from sitting in a nice quiet bin. I don't install any cap without running through my Z meter, and I will toss an entire lot of caps if one is bad. |
| Cursitor Doom <curd@notformail.com>: Aug 25 06:23PM On Sat, 25 Aug 2018 10:39:13 -0700, John-Del wrote: > Heat and charge cycles do affect a capacitor's life, but they're not the > only factors. Humans who smoke, drink, and do drugs have a shorter life > than those who don't, but we all will die eventually. Hmmm. Not really a valid analogy! > up in ESR just from sitting in a nice quiet bin. I don't install any > cap without running through my Z meter, and I will toss an entire lot of > caps if one is bad. I managed to find 8 electros in my bin that could used in parallel to get the equivalent of the failed ones I've removed. I've checked them all for ESR, leakage and Capacitance and the readings I've got have come out indistinguishable from new caps of the same value & voltage rating. I've picked the best 6 (with the lowest ESR) and am re-forming them over the course of this weekend. I'll report back in due course on the success (or failure) of this method. I certainly wouldn't want to hit them with their rated voltage straight away after so long in limbo as that *would* be inviting disaster. -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition. |
| John Robertson <spam@flippers.com>: Aug 25 12:19PM -0700 On 2018/08/25 11:23 AM, Cursitor Doom wrote: > I'll report back in due course on the success (or failure) of this method. > I certainly wouldn't want to hit them with their rated voltage straight > away after so long in limbo as that *would* be inviting disaster. The final test is leakage, set the cap up with an ammeter in series and put it on a power supply running around 75% of the rated maximum voltage. Leakage should be very low after the cap has stabilized. Here is a nice write-up: https://www.nmr.mgh.harvard.edu/~reese/electrolytics/ Heathkit made a great cap checker that we use to check older off the shelf NOS caps. Has the Magic-Eye tube and everything - except ESR. John -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 (604)872-5757 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
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