"Cook" 10BP4 Sencore CR70

[miniman82]

I don't trust the filament supply in my CR-70 anymore, so if I cook a tube I use the universal clips and a variac. I'll let a tube sit at 8v for about 20 minutes and if it hasn't made progress I go ahead and put it through a cleaning cycle. If that fails, it's rejuvenation time. When that doesn't work, it's dead.