Clarified Schematics Introduction
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The diagrams on the yellow sheets in this section indicate the breakdown of the individual bands of the multi-wave band receivers specified in the corner cards and shown in the respective manufacturers sections in the main part of this Manual. Those schematics for which breakdowns have been made bear a designation in the upper margin. The purpose of these breakdowns is to show how the components, that is the coils, condensers and switch contacts, are used when the receiver is set to different bands. In the majority of cases the circuits shown are the r-f and oscillator systems; however, in a few instances, a-f breakdowns are given.
The switch contacts which are associated with the various circuits, are represented as small circles, bearing either numerical or alphabetical designations corresponding to those designations shown upon the complete diagram contained in the respective manufacturers' sections in the main part of the Manual. The connections between the switch points are shown by dotted lines.
Each of the main diagrams, that is complete schematics, shows the wave-band switch in a certain position; usually this is the broadcast band position. This same position is shown as the first position in the breakdown diagram unless the contrary is specified. Reference in the breakdown diagrams to the fact that the switch is shown as having been moved from one position, indicates the first position immediately following either the broadcast band, if that is the first shown, or whatever the band may be which is the first shown.
Expressed differently this is, if the designation is "switoh moved one position" this means that the wave-band switch has been turned one position from the reference point designated as "switch as shown".
When all switches associated with the movement turn in the same direction, this is specified as " clockwise " or " counter-clockwise " as the case may be. You will note that corner cards on some of the " Clarified Schematic breakdowns indicate several receivers. This means that the r-f and oscillator sections, as shown in the breakdown, apply to those receivers. However, this should not be construed as signifying that all these receivers are the same throughout. It simply means that the wave-band positions and associated circuits are the same for each model or chassis listed under the same " Clarified Schematic ".
In some cases sections of the wave-band switch are used to short cirouit coils which are not in operation on the particular band shown in the schematic. In cases where inclusion of these shorted coils unnecessarily complicates the breakdown, they have been omitted, since they are not essential to the operation of the signal-carrying circuits.
In the case of audio-frequenoy circuit breakdowns, the designations shown upon the breakdown schematics correspond with the designations shown upon the complete schematics.
For your convenience the pin terminals for each tube represented in the breakdown diagrams have been numbered according to the RMA system.
You will note that in some cases the bands are identified in accordance with the frequency range covered. Then again in some instances these frequency ranges are omitted. The reason for the omission is that we were unable to identify the specific ranges covered by the various bands and it was felt that, since all receivers do not employ switch arrangements which increase the frequency range in exact sequence as the range switch is advanced, it was deemed advisable to speak simply in terms of the switch positions, rather than the frequency ranges. Of course, where the frequency range was known it has been identified.