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Re: [Amps] How to know when filter caps begin to fail

To: <amps@contesting.com>
Subject: Re: [Amps] How to know when filter caps begin to fail
From: "k7fm" <k7fm@teleport.com>
Reply-to: k7fm <k7fm@teleport.com>
Date: Wed, 28 Mar 2012 20:22:46 -0700
List-post: <amps@contesting.com">mailto:amps@contesting.com>
So, after all the horror stories of exploding caps, I want to mention that a 
few months ago, I removed each original capacitor from one of my Alpha 76A 
amplifiers.  It was fairly low time and had been sitting on the shelf.  I 
reformed each capacitor, measured the capacitance, and they were all within 
factory specs.  I then formed each one, working up to 450 volts, the rated 
voltage.  Each one had very low leakage.  ESR on each one tested as good as 
new.  So, I put them back into the Alpha.  I was also surprised that the 
original carbon composition resistors were each within tolerance and quite 
close to each other.

I could have installed new capacitors, but after passing all these tests, I 
did not hesitate to reinstall them into the amplifier.  Heat contributes 
greatly to the aging process.

Unless I was comfortable with the results of these tests, I would have 
replaced them.  I own and fly an old wood aircraft.  Things get replaced if 
they need replacing - but if they are still good, they do not get replaced.

73,  Colin  K7FM 

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