"Canned Ohm" resistors

The so called 'Canned Ohm " resistor is quite interesting.

 It is a wire wound power resistor, typically used as a voltage divider in earlier radios and TV sets. They are in a crimped on, usually tapped insulated metal casing and it is usually riveted to the chassis.

 The wire wound resistor inside the metal housing is most often tapped, but now and them you will find one that is not.

The main faults with these types of resistors are just very few.

One section opens. Really non repairable. The old techs used to jump a power resistor of the correct resistance and wattage rating over the bad section. (But if that section shorted to the chassis, it can cause the new resistor to quickly fail).
Quite difficult to find a replacement for them these days. I suggest using a wire wound power resistor with sliders to set the taps.

The resistors have a nasty habit of burning through the insulation inside the crimped on metal housing and the resistor shorting to the metal casing which is riveted to the chassis.

They were used in both TV sets and radios. 

In reality, I have seen very few actually open or short to ground. Rarely will the resistance wire inside short turns. They can get rather hot in operation. "Canned Ohms" came in a variety of wattages and resistance ratings too.

I listed the main failures, as unless you know what they are, it can be confusing and difficult to find one that has failed. 

Look them over carefully. Sometimes when they fail the thin Bakelite insulator in the resistor will show overheating or burn marks.