Dog Bone resistors

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My tests show all the older carbon comp resistors like dog bone ones increase in ohmic value. In my KB 428 a very large looking 3 watt 600 ohm one is now 800 ohm.

Mike

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If you want authenticity in my view it is probably best to find a 500R one and if it is 600R, repaint in correct colours.
It is interesting to note that the smaller resistors that KB used in the early to mid 30's seemed fairly reliable in value. But in the case of my 428 a few were open circuit due to high leakage caused by capacitors that had gone bad.

Below are a few examples of the types found in a 1935 KB radio.
   
I initially thought they were normal dog bone solid carbon types, then I changed my mind when I started to discover many of them were wire wound and very accurate. I have now found that the higher values were carbon film on what appears to be a ceramic body.
These 3 are all open circuit.

Were these types of resistors used in other makes of radios or are they unique to KB.



Mike