Show radio advice from expert herbert E metcalf Met calt radio engineer ot of the Magno vox co 0 oakland al cland calif gives some simple yet sound advice to all radio fans who wish to get the best results from their sets when he be says ays 9 everyone knows that the one cardinal virtue ot of a first class clasa radio E set let Is soldered connect connections ious the fact that every point should be carefully cleaned and then securely soldered has been brought forcibly to our attention in practically every writ written teni article about radio set building we are also continually being cautioned about soldered antenna joints and proper ground clamps i j when men we buy any set get of 0 good I 1 quality we naturally tak take e it tor for granted that all joints are secure because they are most carefully tested before being sent out we then install our set solder all an antenna lenna joints put in a good ground clamp scrape and carefully apply all battery connections and everything is fine until some day we hear a noise such as caused by y a poor connection some cheze perhaps the noises get worse and worse and upon investigation find all joints still secure what then the tact fact is that there are at least 22 92 contacts in a 5 tube set which cannot even be soldered twenty of 0 them tare are tule tube prong contacts and the other two are the battery switch and the rheo stait dirt on any one ot of these will be a fruitful source ot of noise many tubes have solder lead alloy on their base abase prongs this ailder rubs off onto the socket contacts oxidizes and makes a high resistance ce noisy connection tion the battery switch la Is often liable to dirty up after contin continued aed switching and must be cleaned the same with the rheostat imagine trying to run an automobile and never cleaning the distributor or timer A dirty distributor contact in a motor causes missing a dirty switch or rheostat contact causes noise la in a radio set the remedy is 13 of course cleaning keep the ithe tube prongs bright and shiny solder will oxidize and blacken more quickly in some climates than others it Is not enough to clean the prongs clean the socket contacts also clean the battery switch contacts as you would a distributor in an automobile if the rheostat needs cleaning any movement of the knob will eau cause se the noise to change fine sandpaper may be used or even a pencil rubber but never use a tile file or hard emery cloth its just the very surface oxidized and a light cleaning until the medal is bright Is sufficient the next time the set gets noisy t try ry cleaning the contacts or better have to apologize tor for a dirty contact yet why not do it regularly and not during a concert |