[R-390] Speaking of C709

[n4buq at knology.net]

The specs call for a 300V capacitor for C709.  I assume this is just 
because this is what was commonly available, right?  With only a few volts 
across the output, is there any other reason to insist on a 300V capacitor 
here?

Thanks,

Barry - N4BUQ

> I'm seeing about 1.8V peak-to-peak, unterminated into my 'scope.
> 
> The more I think about this, the more I'm wondering if C709 might be bad.
> Wouldn't this cause low output?  It's spec'd as a 2% so I'm thinking if it
> has changed, even slightly, it might be causing a problem.  If I recall,
> C327 (the cap across L230/T207) is of the same type and it has been known 
to
> cause low output from the 1st crystal oscillator.
> 
> I haven't found a 510pF, 2% cap yet, though.  :-(   Surplus Sales of
> Nebraska has them, but they also have a $10 minimum order and I really 
don't
> need anything else from them right now.  Any sources, anyone?
> 
> Barry - N4BUQ