[sdiy] Dead capacitors

[Harry Bissell]

Dead polystyrene caps are not common... but

They can be damaged by some chemicals (be careful of what you clean the PCBs with)

They can get broken leads from vibration especially with the radial lead parts 

They can be damaged easily by soldering, Their ability to withstand heat is very limited !

H^) harry

----- Original Message -----
From: dan snazelle <subjectivity at hotmail.com>
To: Synth-Diy diy <synth-diy at dropmix.xs4all.nl>
Sent: Wed, 11 May 2011 08:38:07 -0400 (EDT)
Subject: [sdiy] Dead capacitors

This week I spent a few days trying to repair a broken Tracer City. I was the second person who had tried to repair it.

After a about 10 hours of testing I finally found the culprit

the entire circuit was being taken down by a shorted Polystyrene 220pf capacitor!!!!

(It was in the feedback path of an integrator opamp, which happened to be the Low pass stage of a filter.....so it killed the rest of the filter
which meant that the sound of the entire box was no good)


What I am trying to figure out is 

1. are polystyrene caps prone to Failure? IF so, under what conditions?

2. Are DUD poly caps common?


I have never encountered this problem before.


thanks!






http://www.youtube.com/user/snazelle



_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy

-- 
Harry Bissell & Nora Abdullah 4eva