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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>There are bad years and suppliers for SMT electrolytics that do leak and corrode PCBs. The corrosion takes out runs and vias. We see this at the vintageTEK museum. We refer to the incident as the “caps pee’d all over the PCB”. At that point we consider them toast but I have seen people work to restore the PCB. It is a lot of work.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><br>Dave<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt'><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Synth-diy [mailto:synth-diy-bounces@synth-diy.org] <b>On Behalf Of </b>Pete Hartman<br><b>Sent:</b> Monday, June 18, 2018 3:56 PM<br><b>To:</b> synth-diy@synth-diy.org DIY<br><b>Subject:</b> Re: [sdiy] Korg Delta problem<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>I literally had spew from an SMD electro corrode and damage the PCB on a Roland XP-50.<br><br>I had another synth where I couldn't get it to do anything until I replaced some mylar caps in the psu section.<br><br>So yeah, caps go bad.<br><br>Acknowledging that is NOT the same thing as "MUST RECAP EVERYTHING" shotgun "troublshooting".<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Pete<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div></div><div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>On Mon, Jun 18, 2018 at 5:45 PM, <<a href="mailto:sleepy_dog@gmx.de" target="_blank">sleepy_dog@gmx.de</a>> wrote:<o:p></o:p></p><p class=MsoNormal>Gordonjcp wrote:<o:p></o:p></p><p class=MsoNormal>On Mon, Jun 18, 2018 at 10:01:45PM +0200, Jean Bender wrote:<o:p></o:p></p><p class=MsoNormal>thanks !<br>you mean the caps from the power supply ? How could the power supply<br>only disturb or make no functionnal only half part from the synth ?<o:p></o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'>You'll never find "bad caps" in a synth. They're pretty much a myth.<o:p></o:p></p><p class=MsoNormal>How so? Is it a myth that electrolytic caps will chemically degrade?<br>I have been told by more than one EE not to bother using electrolytics that have been laying around for 5 years, not just for things requiring low ESR, not for anything.<br><br>I don't have any numbers. But even in some simple old synth PSU with a pair of fat caps and linear regulation, it would be bad if those caps got a huge ESR and reduced capacitance, no? Now I can imagine that this is considered in the circiut designs, but only so much?<o:p></o:p></p><div><div><p class=MsoNormal><br><br><br>_______________________________________________<br>Synth-diy mailing list<br><a href="mailto:Synth-diy@synth-diy.org" target="_blank">Synth-diy@synth-diy.org</a><br><a href="http://synth-diy.org/mailman/listinfo/synth-diy" target="_blank">http://synth-diy.org/mailman/listinfo/synth-diy</a><o:p></o:p></p></div></div></div><p class=MsoNormal><o:p> </o:p></p></div></div></div></body></html>