Motorola 57W

[Jeffhs]

Originally Posted by dieseljeep

I was going to mention the pilot lamp. If it's not replaced, the life of the 35W4 tube will be shortened.

This can happen with Zenith (and other) radios as well. I have an H511 in which the pilot light burned out due to a deformed filter capacitor in the power supply (I had purchased the radio used on eBay, so it may have been sitting in someone's basement, garage, etc., unused, for decades, which could very easily account for the deformed 3-section power supply electrolytic). The radio worked with the burned-out lamp, but the 35W4 ran so hot it would have burned out in short order if I had kept the set on very long.

Replacing the pilot lamp cooled down the tube and the radio worked normally after that. Many AA5 radios used a #47 pilot lamp, placed behind a decorative emblem (as in the Zenith H511 series). The bulb will illuminate very brightly for a fraction of a second when the radio is switched on; when the tubes are fully warmed up, the pilot lamp will glow at normal brightness. VK member wa2ise mentioned in a post here some time ago (I don't recall where that post is anymore) the importance of the pilot light in many AA5 radios. Needless to say, the radio should not be used until the pilot light has been replaced.