[Hallicrafters] SR-400A cathode resistors

[james.liles]

Hi Walt:

Should ahve included the rational.

The problem with these resistors is that they are carbon composition carrying RF.  They have the same skin effect properties as wire --- the flow is forced to the surface causing the resistor to overheat even though the rated heat as calculated for DC is not exceeded.  The 10 meter segment of the SR-150 tank is nearly always melted --- same reason.  A good choice for a replacement is carbon film or metal film resistor.  Or if using a carbon composition, watts times four at HF.     Kindest regards Jim K9AXN