[R-390] killer and mica caps

[Larry H]

Sorry Renee, There are no fuses that I know of that would open before the filter would be damaged.

Chris, no need to hide, this is a good learning tool.

I also wanted to define what I meant by test the cap before installing.  Apply the rated voltage (not higher than) and look for leakage with a sensitive amp meter (around 50 micro amps full scale) in series with a 10k ohm resistor.  If there is any current flowing at all, do not use it for C553.

As for measuring the distortion, in this situation, you would need to be able to measure the IMD of the IF unit.  This takes special equipment, but in any case, this is a sensitive cap for minimizing IMD.

Clearing 'self healing' event possibilities can not be done today, as was pointed out, they normally occur because of contamination (and other issues) in the manufacturing process, and it takes a varying amount of time for insulation penetration/breakdown to occur.  However, you could test them as the manufacture does, with a recording scope monitoring for current spikes while measuring for leakage for an extended time.  If you apply twice the rated voltage and you see no leakage, that does not mean that an event will not occur in a few months or a couple years. 

I am all for finding a longer life cap for C553.  Does anyone know of any tests done by independent testers?  I'm not too keen on believing this kind of data provided by a manufacturer.

Regards, Larry