We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
580 RICHARDSON'S BLUEBOOK OF PROJECTION
some sound circuit in which no tube supply flows, as, for example, an open circuit in Condenser C-6, in coil L-3, or in the primary of T-l. Or the primary of T-l might have been short-circuited by the grounding of one of its terminals. When the location of the trouble has been brought clown, by such tests as these, to an extremely small area, visual inspection and tugging at wires usually gives faster results than further application of test meters or headphones. In such inspection one looks for signs of overheating, melted insulation, or a bad soldered joint, also for some hair-thin strand of wire that may have grounded a sound circuit.
Assuming, on the other hand, that the loss of sound has been traced to some one stage and the tube voltages have been found not normal, then the procedure is to run down the supply line of the abnormal circuit, looking for an open, a short or a ground. This is best done with a portable voltmeter, but it can also be done visually and by tugging wires.
Once trouble within an amplifier has been traced to some single circuit the speed with which it is cleared up is largely a matter of the common sense of the troubleshooter, and of the extent of his grasp of the simple fundamentals that are common to all electrical circuits.
Loss of sound in an amplifier is not a trouble difficult to find. The chief requirement in finding it, when it occurs during a show, is speed. Speed is secured, first, by glancing at all tubes to make sure that they are lit, and by taking all meter readings. Second, by making sure the trouble is actually within the amplifier, using headphone tests as described. Third, by locating the particular stage or circuit within the amplifier that is at fault, using either meters, portable meters, or headphones, whichever comes fastest. (In the case of Figure 140 the meters make headphone tests almost unnecessary; in the case of Figure 139 the chances are that using the phones will prove faster than resorting to portable meters.) Fourth, detailed examination of the precise circuit or stage found to be at fault. Fifth, in those rare cases where there is no indication of trouble in the circuit