My Drake R-4B works fine but sometimes when I turn it on the OB2 tube puts
on a light show with swirling orange glow brightening up the inside of the
radio. It was kind of scary the first time I saw it. Usually when it does
that if I turn it off once or twice it stops doing that. Is this a cause for
concern? Is the tube going bad or indication of some other problem? I don't
have a spare of that tube on hand but I can get one on Ebay for not much.
Thanks.

Steve