CRL 857 or 859 doorknob capacitor

[W8ACR]

I need a blocking capacitor for my T-368 which I have converted to a standard shunt fed pi network tank circuit. I was using a very hefty CRL 859 500pf unit, but some arcing from the nearby plate choke destroyed it. I need a new blocking capacitor. Looking for another 859 or 857, 500 or 1000pf.

Thanks, Ron W8ACR