Also, these show up a lot in what seems to be a common condition: Sellers report, basically, "half the tubes glow and the other half don't" and of course it isn't working. Does that description make any sense, as some common type of TO failure?
Thanks
Rick
You can find information on Zenith T/O's here:
http://www.transoceanic.nostalgiaair.org/
These radios are battery operated. Tubes have small filaments. You shouldn't be able to see filaments lit unless in a dark room. Filaments are wired in series so if one tube is lit all should be. There is always a possibility something shorts and some tubes wouldn't light but unlikely.
Norm
:Suject line pretty much says it all. I'm looking at a TO and I know the chassis number is 6A40. But this site says that chassis was used in both the A600 & B600.
:
:Also, these show up a lot in what seems to be a common condition: Sellers report, basically, "half the tubes glow and the other half don't" and of course it isn't working. Does that description make any sense, as some common type of TO failure?
:
:Thanks
:
:Rick
:
It is typically a wise idea to replace old electrolytics and paper capacitors. In two of my three Zenith portables (5-G-500 and 6-G-601), the electrolytics function like new, and so I have yet to replace them. Until AM radio took a serious dive in programming, I used to use those radios on a very regular basis, and never had trouble with the electrolytics. However, my third Zenith portable, and my other two portable radios (Airline and General Television) did need electrolytic replacement. Just about all radios I own needed paper capacitor replacement. You can probably expect to replace capacitors in your radio, too.
With battery type tubes it is wise to be extra cautious with the filaments. While shorts across the filament string aren't likely to cause devistation, other things to watch out for are accidental shorts from B+ to the filament string (while you're working on the radio). You should also never pull a tube wiht the radio running. The ballast resistors become unloaded, and feed the electrolytics full B voltage. When the tube is plugged back in, near full B voltage (around 90-120 volts) will be applied to the filament string, which might possibly burn out multiple tubes.
T.
What Thomas mentioned about having the radio off, when replacing tubes, is very important. Tubes are wired in series and high voltage is dumped across the string if power isn't removed. Usually the first one to burn out protects others.
Some of us know by experience. Seem like this is one experience that keeps getting a person. Probably burned out 10 tubes this way.
Norm
:If C41D were to short out or need reforming (which might mean that it would draw excessive current), it would short across some of the tubes, causing them not to light.
:
:It is typically a wise idea to replace old electrolytics and paper capacitors. In two of my three Zenith portables (5-G-500 and 6-G-601), the electrolytics function like new, and so I have yet to replace them. Until AM radio took a serious dive in programming, I used to use those radios on a very regular basis, and never had trouble with the electrolytics. However, my third Zenith portable, and my other two portable radios (Airline and General Television) did need electrolytic replacement. Just about all radios I own needed paper capacitor replacement. You can probably expect to replace capacitors in your radio, too.
:
:With battery type tubes it is wise to be extra cautious with the filaments. While shorts across the filament string aren't likely to cause devistation, other things to watch out for are accidental shorts from B+ to the filament string (while you're working on the radio). You should also never pull a tube wiht the radio running. The ballast resistors become unloaded, and feed the electrolytics full B voltage. When the tube is plugged back in, near full B voltage (around 90-120 volts) will be applied to the filament string, which might possibly burn out multiple tubes.
:
:
:T.