Quoting Martin Sole <hs0zed at gmail.com>: > I recall someone used to say, air around a tube is a good thing and > the only time you have too much air is when the tube will not stay > in the socket! Thats what Bill Orr told me about 4CX250Bs in the mid 70s. "If they pop out of the sockets, back the air down a bit. Don W4DNR