Interesting superhet
 

Last four or five days I've been home with the flu. Not the h1n1 thank God but still very unpleasant. Anyway I ran across this video of repair of a Philco 70. http://www.youtube.com/watch?v=lNMo1NuvTRA The gent has an interesting way of describing how the signal goes though the front end and how the tubes amplify each other. Starts at 4:51 into the video.
Was wondering how did Philco on their early '30s chaiss make them gray? I don't think it's paint so was it some sort of treatment to the metal?
Terry