Radio Broadcast (May 1929-Apr 1930)

Practical Talks to Service Workers — IV VALUE OF FUNDAMENTAL KNOWLEDGE By JOHN S. DUNHAM QRV Radio Service, Inc. A great deal of discussion has arisen about the questionnaire published in the April, 1929, Radio Broadcast which is used by the QRV Radio Service, Inc., as an examination of applicants for the position of radio servicemen. Insofar as we have been able to ascertain it, the consensus is that the examination is more difficult than would be necessary to determine the ability of a good serviceman. We have talked with a considerable number of representative service managers and servicemen, most of whom feel that a good serviceman need not know enough to obtain a passing mark on that examination. Some few of the service managers with whom we have talked very heartily approve of the test and there have been a few who thought such an examination might justifiably be made even more difficult; but those who entertained that opinion have been distinctly in the minority. The purpose of this article is to illustrate the value of the knowledge possessed by a serviceman who could obtain a good mark on that test. We shall attempt to do that by taking each question or group of questions separately and discussing just how the knowledge required to answer that question can be of practical aid in the servicing of broadcast receivers. Service Standards It is our opinion that one of the greatest troubles with the service game to-day is lack of realization on the part of the average serviceman that servicing broadcast receivers is a difficult technical pursuit, requiring both general and specialized electrical training. Because the average serviceman does not realize that fact, he is, as a rule, making little effort to provide himself with the technical knowledge pertaining to his work, without which he can never become a thoroughly efficient worker in the field he has chosen. It is our belief that the generally accepted standard of knowledge possessed by men who are considered "good" servicemen has been far too low, simply by virtue of ignorance on the part of the average employer of servicemen that there are men who know a great deal more about their work, and that an intelligent serviceman can be trained to know more — and thereby become more efficient — than has been generally thought necessary. It has been our experience that a man who cannot make a grade of at least 70 per cent, on our examination has not enough general knowledge of broadcast receivers to be a successful serviceman This motorcycle service and delivery truck is cutting doivn service costs for Atchison's Radio Shop, Philadelphia, Pa. without a great deal of further training. And by a successful serviceman we mean a man whose work is not followed by a number of return calls, within two weeks, greater than 5 per cent, of the calls made by that man. The return call records of the work of three men employed by QRV, compared wit h their marks on the test, illustrates the point very clearly. One of these men — who is no longer with us — obtained an examination mark of 60.5 per cent. Over a period of four months, his work was followed by 14.4 per cent, no-charge return calls. The second man had a mark of 81.5 per cent. His work for the same period was followed by 4.3 per cent, return calls. The third man achieved a mark of 96.75 per cent. His work for the period was followed by 0.7 of one per cent, return calls. Each of the three men made approximately the same number of calls during that period. Replacing Rheostats ome of the servicemen animation to be of value, taken as a whole, are of the opinion that the portion of it in which we attempt to ascertain the knowledge of simple fundamentals possessed by applicants is an entirely unnecessary requirement. It is our opinion, and it is well borne out by long experience, that a thorough knowledge of the simple d.c. and a.c. circuits is exactly as important a part of the serviceman's working equipment as is his knowledge of how to locate an open in a plate circuit. For example, let us assume the case of a burned-out rheostat in an old set, the manufacturer of which is no longer in existence and for which no parts catalogue is obtainable. In such a case it is extremely rare to find the resistance value of that rheostat marked on it. The serviceman is faced with the problem of determining the proper value of resistance with which the damaged rheostat must be replaced. If he does not possess a working knowledge of Ohm's law, the only method by which he may determine the proper size of rheostat to get is to remove whatever remains of the resistor element of the damaged rheostat and take it with him on a time-wasting search for a new rheostat, the size and length of whose wire appears physically to match that of the old one. On the other hand, if he is familiar with Ohm's law he will take out his pencil and set down the familiar fact that R = E/l. He will then multiply the filament current drawn by one tube by the number of tubes controlled by that rheostat, to get the total amount of current through the rheostat. He • JULY 1929 • • 145