"Talk to any busy TV serviceman and he'll tell you that he makes many unneccessary calls. The repairs were simple, perhaps a minor adjustment or loose connection. The set owner could just as well have made them himself. The job may have taken the serviceman only a few minutes. But his fee must include traveling time, too. So far as the set owner is concerned, the charge is out of proportion to the service rendered. Because of this, it will pay you to become familiar with some of the more common trouble symptoms that ocur in a television receiver."
Popular Science Publishing Co. Inc., 1957