Trouble Finding

Radio Record, Volume III, Issue 26, 10 January 1930, Page 29

Trouble Finding

ne When the Set Goes Dead F the possible radio troubles which may stop reception entirely, only a few vccur with any degree of frequency. Therefore, when the set goes dead, it is well to check first the points where trouble is most likely to be found. For example, since a burned-out valve is perhaps the most common trouble with all electric sets, look first to make sure that all valves are working. If: they glow about normal, that daes not necessarily prove that they are operating with full efficiency. The manner in which the receiver stopped will give some clue on this point. If the signals gradually faded away over the course of several days, one of ‘the valves probably has become exhausted, The filament is lighting in the usual manner without producing

the normal flow. of electrons. In that case the best thing to do is to take all the valves to the nearest radio dealer and have them tested. . The fact that the signal faded out gradually also indicates that the trouble ix not due to a broken wire, because such a break would cause the set to go out of commission suddenly. After the valves have been checked and it is known that "hey are good, the next test is to tap gently all of the valves in the receiver with a finger nail. When the detector valve is struck there should be a clear ringing sound from the loudspeaker. If not, something is wrong in the audio amplifier end of the set, between the detector valve and the loudspeaker. If the audio amplifier circuits are in good shape, the next step, assuming that the receiver is in a locality where there are one or more powerful local stations, is to remove the radio-frequen-ey amplifier valve next to the detector valve, and also disconnect the antenna wire, Carefully place the antenna lead-in in the plate prong hole in the empty socket. Be sure that the antenna lead dues not touch any metal in the set. With this connection the circuit becomes a plain detector circuit followed by the audio amplifier, and if signals are received under such conditions it indicates that the trouble is somewhere in the radio-frequency amplifier circuit. By replacing the valve and trying the test on the next valve

in line toward the antenna end of the set, you ean test the radio-frequency stages one by one and find where the trouble actually is,