Resistor reliability question

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These old resistors are usually referred to as "dogbones", and are carbon. They are a different manufacturing process than carbon comps, but treat them the same. If they drift in value, it's usually up.

Many people have reported the same experience as radiotvnut, so check them all. I have had much better luck with them, however. I dont ever remember having to change all of them in a radio.

In the radio I am currently working on, all the dogbones were still well within tolerance, and most of the striped carbon comps were shot. Oh, and by the way, if there is no tolerance mark, a dogbone is a 20% tolerance part, just like a normal striped carbon comp. The tolerance mark, if it's there, will be a blob of paint on the normally unmarked end of the resistor. Silver for 10%, gold for 5%, just like a striped one.

The smallest, most common size of dogbone is 1/4 watt (and those are physically a little bigger than a 1/2 watt carbon comp. After the change to the striped resistors, 1/2 watt became the smallest common size. This is because 1/4 watt carbon comps are physically tiny, and usually have a farily low voltage rating.

John