While recapping a radio, I came across a capacitor that I first thought was a dogbone shaped wire wound resistor. But after checking the schematic, I realized it was a 68 mmF capacitor.

Can anyone tell me what kind of cap this might be? Its brown with stripes similar to a resistor but has a radial form factor.

The radio works OK with this cap in place but I'm curious about it in case I ever do need to replace it.

Thanks,

Randy

You will probably never need to replace that condenser, as they almost never short. It is a tubular ceramic (sometimes other materials) condenser. It is made by placing a metal tube (or foil or forming a metal film) inside a predetermined thickness porcelain tube, and then another on the outside. The inner metal tube hangs out one side of the porcelain tube just a bit. The thickness of the porcelain is not extremely important except for voltage purposes, because the condenser may simply be cut to proper capacitance by cutting off the end that does not have the inner metal tube exposed. One lead wire is connected to the outer metal tube, and the other wire is connected to the exposed end of the inner metal tube. Sometimes the whole thing is dipped in epoxy or some other material, and sometimes the unit is left exposed...sometimes painted and sometimes not. Color dots are usually used for a value marking. The coding is usually not like the dogbone coding system, but rather dots in a row.

If you want another confusing one, Micamold made mica condensers in their familiar package with the arrow and dots, and they also made wire wound resistors in this package. The resistor will have three color dots in a row just like the color bands on a modern resistor. Then off to one side you'll likely find a silver or gold dot for tolerance. The color dots are read in the direction of the arrow. Suddenly, when you come across a Micamold condenser that is shorted, you may have just run into one of these resistors! Joy! Usually they are found in B+, B-, cathode, and filament circuits, though, which is somewhat of a tell-tale.

:You will probably never need to replace that condenser, as they almost never short. It is a tubular ceramic (sometimes other materials) condenser. It is made by placing a metal tube (or foil or forming a metal film) inside a predetermined thickness porcelain tube, and then another on the outside. The inner metal tube hangs out one side of the porcelain tube just a bit. The thickness of the porcelain is not extremely important except for voltage purposes, because the condenser may simply be cut to proper capacitance by cutting off the end that does not have the inner metal tube exposed. One lead wire is connected to the outer metal tube, and the other wire is connected to the exposed end of the inner metal tube. Sometimes the whole thing is dipped in epoxy or some other material, and sometimes the unit is left exposed...sometimes painted and sometimes not. Color dots are usually used for a value marking. The coding is usually not like the dogbone coding system, but rather dots in a row.
:
:If you want another confusing one, Micamold made mica condensers in their familiar package with the arrow and dots, and they also made wire wound resistors in this package. The resistor will have three color dots in a row just like the color bands on a modern resistor. Then off to one side you'll likely find a silver or gold dot for tolerance. The color dots are read in the direction of the arrow. Suddenly, when you come across a Micamold condenser that is shorted, you may have just run into one of these resistors! Joy! Usually they are found in B+, B-, cathode, and filament circuits, though, which is somewhat of a tell-tale.

Thomas,
And as if the Micamold mica condensers and resistors in the similar package were not confusing enough, Micamold also made paper caps in this same rectangular package with arrows and dots. Usually these were in line filter applications, but they will sometimes turn up elsewhere in a radio and can easily be mistaken for mica caps. And of course the name "Micamold" just adds to this confusion.
Poston