[Retro Ron]

You are correct. The buffer capacitor is generally rated for much higher voltage. In a pinch, I have used two 630V capacitors in series observing the laws of parallel capacitors. The more I experiment with this radio, the more I am convinced it was just time for the vibrator to die. It had probably been operated with a bum buffer capacitor and leaky filters for just too long. Plus the vibrator has a nasty dent in the side which although shouldn't have affected its operation, is rather unsightly.

Regards,
Ron