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Foreward[NOTE: This guide is based on the 1939 Rider book: Servicing by Signal Tracing.]
DURING the past decade the technical problems of the radio serviceman have been increasing in direct ratio to the progress which has been made in receiver and tube design.
Engineers' dreams have been many and varied these last few years and their realizations are little short of marvelous when radio reception of today is compared with that of the early 1930's, but unfortunately servicing technique has not kept pace with developments.... Far too many servicemen are still using Stone Age testing methods.
It was with the primary idea of giving the servicing fraternity a technique that would be universal in application and as useful when applied to tomorrow's sets as to those of yesterday that we started laboratory research for a testing method that eventually developed into the one described in this book. First of all we cast about to find some one factor that was common to all receivers on which we could base our system of testing and this common denominator was found to be the signal. Trace the signal through a receiver until it departed from normal--and there was the point in the circuit where the trouble originated.
That the theory was sound was proved in the laboratory and since its presentation to the radio servicing fraternity it has been acclaimed by thousands of workers in the field--research and design engineers and servicemen--because it has made for speedier and more accurate localization of trouble.
Realizing that a successful application of signal-tracing technique depended upon the knowledge of how the signal behaved in the several circuits of a receiver and how it was affected by the various components which made up these circuits, it was felt that a book describing these subjects was decidedly in order. . . And in broad terms, that is what we have endeavored to give you in this book. You will find sections devoted to the behavior of the signal in detectors, amplifiers, coupling devices-and we believe that these will present a new conception of the functioning of these pieces of apparatus to many of you. Bear in mind as you read, that the signal--and the signal alone--is the all-important factor.
Strictly speaking, our first thought was the development of a system for testing receivers, but as we progressed in our studies we found that signal tracing could be equally well applied to all forms of communication wherein electronic apparatus acted upon a signal. Thus our scope was broadened to include television, public-address and intercommunication systems, facsimile, sound pictures, aircraft and amateur radio, etc. Fundamentally, many of these different forms of electrical communication are alike and so you will find only the broad viewpoint taken throughout the text. However, if you will think in terms of the signal-its frequency and amplitude-the arrangement of the apparatus through which it passes will make little difference . . . the principles underlying the functioning are the same.
It is our sincere hope that this book will change the cumber some and haphazard testing methods of its readers to one which is all-embracing in its scope--a technique that is purely functional and dynamic and at the same time is easily and quickly applied and accurate in its findings. We believe that the adoption of such a system is a necessity in view of all the complications in the servicing industry and in view of the future needs in all branches of the communication field.
--- JOHN F. RIDER. October 23, 1939.
Also see: How to use TEST PROBES (1954)