Eighty years ago this month, the October 1946 issue of Radio Service Dealer carried this ad from GE about the facts of life, namely, the importance of good replacement dial lamps for your radio.

Of course, it wasn’t just a cosmetic issue.  In an All American Five receiver, the dial lamp played an important role, and you would want to replace it as soon as possible if it ever burnt out.   It was wired generally directly across a tapped heater section of the rectifier tube. In this spot, the bulb acted as a current-cushioning ballast that absorbed the dangerous power surges that occur when cold vacuum tubes first switch on.  Running a radio with a dead dial light overloaded that rectifier filament, quickly destroying the expensive tube and disabling the entire set.