Hi folks,
Some time ago I got (for very cheap) a bag of 200 Sanyo OS-CON SA series, 220uF/10V, manufactured January 1988. Measured a few of them and the readings were all over the place so I put them in storage.
Fiddled with them one more time today, to decide if I keep or throw them away, and noticed that strange readings are due to a layer of practically invisible oxide that developed on the leads. Rubbing them just a bit with fine sandpaper or even with the tester probes and they can be tested OK, tried with 10 of them and they mostly measure towards 250uF, with one or two being closer to their rated 220uF, and ESR is about 25-30mohm.
Searched the 'net for information about their shelf-life, couldn't find anything useful. Do you think they can be used after all those years? Is there anything that can dry out or otherwise deteriorate inside them (I suppose they are solid electrolyte)?
Some time ago I got (for very cheap) a bag of 200 Sanyo OS-CON SA series, 220uF/10V, manufactured January 1988. Measured a few of them and the readings were all over the place so I put them in storage.
Fiddled with them one more time today, to decide if I keep or throw them away, and noticed that strange readings are due to a layer of practically invisible oxide that developed on the leads. Rubbing them just a bit with fine sandpaper or even with the tester probes and they can be tested OK, tried with 10 of them and they mostly measure towards 250uF, with one or two being closer to their rated 220uF, and ESR is about 25-30mohm.
Searched the 'net for information about their shelf-life, couldn't find anything useful. Do you think they can be used after all those years? Is there anything that can dry out or otherwise deteriorate inside them (I suppose they are solid electrolyte)?
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