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<TITLE>RE: [sdiy] Lifespan of Electrolytics?</TITLE>
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<P><FONT SIZE=2>I just purchased a kit (of course) of an ESR meter that supposedly will find faulty caps due to their high ESR reading. Anyone here have experience with it? </FONT></P>
<P><FONT SIZE=2>I'd like to say I have a recent memorymoog aquisition I'm fixing with it but in reality its a Philips Magnavox 27" TV....</FONT></P>
<P><FONT SIZE=2>Barry</FONT>
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<P><FONT SIZE=2>-----Original Message-----</FONT>
<BR><FONT SIZE=2>From: Byron G. Jacquot [<A HREF="mailto:thescum@surfree.com">mailto:thescum@surfree.com</A>]</FONT>
<BR><FONT SIZE=2>Sent: Monday, May 20, 2002 8:02 PM</FONT>
<BR><FONT SIZE=2>To: synth-diy@dropmix.xs4all.nl</FONT>
<BR><FONT SIZE=2>Subject: Re: [sdiy] Lifespan of Electrolytics?</FONT>
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<P><FONT SIZE=2>> I recently got ahold of a Tapco 4400 reverb for cheap because one channel</FONT>
<BR><FONT SIZE=2>>was dead. After chasing down a handful of 4136s and systematically replacing</FONT>
<BR><FONT SIZE=2>>each one, I came to find that the actual problem was a bad electrolytic in the</FONT>
<BR><FONT SIZE=2>>signal path. The circuit board is dated 2/17/77. I'm guessing that several</FONT>
<BR><FONT SIZE=2>>more of the caps in this board are marginal. What is the expected lifespan of</FONT>
<BR><FONT SIZE=2>>electrolytics, and what are the effects of old and aging ones? Is it worth the</FONT>
<BR><FONT SIZE=2>>trouble going through any old gear including synths that are past, say, about</FONT>
<BR><FONT SIZE=2>>twenty years and giving them a electrolytic overhaul? Anyone have firsthand</FONT>
<BR><FONT SIZE=2>>(or secondhand) testimonials? Thanks.</FONT>
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<P><FONT SIZE=2>I've got a mixing console that's about 15 years old, I've owned it for about</FONT>
<BR><FONT SIZE=2>3 of them. I knew it was old enough that the 'lytics were going to be</FONT>
<BR><FONT SIZE=2>questionable, but just how important recapping can be hadn't really hit home</FONT>
<BR><FONT SIZE=2>yet. The first time I tried to do serious work on it (more than just firing</FONT>
<BR><FONT SIZE=2>it up for 15 minutes to make sure things were wired right), it started</FONT>
<BR><FONT SIZE=2>making this "tik-tik pop tizzz.." kinda noise. Just loud enough that I</FONT>
<BR><FONT SIZE=2>couldn't get any work done.</FONT>
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<P><FONT SIZE=2>I pulled out the oscilloscope, to see if I could figure out where the noise</FONT>
<BR><FONT SIZE=2>was coming from. It seemed to be everywhere...every insert point, every</FONT>
<BR><FONT SIZE=2>output...</FONT>
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<P><FONT SIZE=2>I started unhooking channels, one or two at a time. When I unhooked a</FONT>
<BR><FONT SIZE=2>channel, the noise would disappear for a little while, then come back,</FONT>
<BR><FONT SIZE=2>insistent as ever...even with large portions of the thing unhooked, the</FONT>
<BR><FONT SIZE=2>noise was still there. With the thing opened up, I started checking for</FONT>
<BR><FONT SIZE=2>some "common sense" things, like power & ground & solidity of the multipin</FONT>
<BR><FONT SIZE=2>connectors...</FONT>
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<P><FONT SIZE=2>Lo & behold, the positive rail would "dance" in time to the ticking noises,</FONT>
<BR><FONT SIZE=2>jumping between 16.75 V and 17 V...at that point, I got out the Digikey</FONT>
<BR><FONT SIZE=2>catalog, and ordered a whole slew of Panasonic caps. I got on with the</FONT>
<BR><FONT SIZE=2>recapping I'd anticipated.</FONT>
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<P><FONT SIZE=2>The noise is gone now...and I'm sititng here with something like a pound of</FONT>
<BR><FONT SIZE=2>used electrolytic caps that were pulled from the board. One of those caps</FONT>
<BR><FONT SIZE=2>is bad, and only shows it when it heats up!</FONT>
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<P><FONT SIZE=2>Byron Jacquot</FONT>
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