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Radio Broadcast
the panel in their proper position as the operation of the set would be affected if they were even slightly moved out of position during assembly and wiring.
WIRING UP THE FIVE-TUBE NEUTRODYNE SET
THE wiring of a receiver is usually the stumbling block for most of the experimenters. I have seen some of the most horrible looking jobs on neutrodyne receivers, yet when the job was properly balanced out, it worked O. K. This should not be taken as a criterion, however, and the experimenter is advised to take particular pains in wiring up his set.
Study the wiring diagram in Fig. 3 very carefully. Note in particular the polarity of the Neutroformer windings, audio-frequency transformers, and especially the connections of the Neutrodons and telephone jacks. All high-potential plate and grid leads should be kept as widely separated as possible and all wiring separated at least one half inch with as few leads running parallel to one another as possible.
In assembling the receiver, it is usually best to fasten the base board to the panel, and to fasten the audio-frequency transformers and Neutrodons to the base board. Before wiring up the receiver, however, one should unfasten the base board from the panel, as this makes it much easier to wire all the parts mounted on the panel. Then fasten the base board with its Neutrodons and audio-frequency transformers again into place to complete the wiring of these units.
It is usually best to begin wiring by connecting all the negative vacuum-tube socket terminals and then extending this same wire to the ground binding posts. In like manner, the
positive filament connections can be made and the wiring of the detector tube rheostat, power rheostat, battery switch, and battery binding posts completed.
Connections to t he Neut reformers come next. It will be noted that all the Neutroformer secondary windings have a small loop or tap. On the wiring diagram no connection is made to the tap of the first or left hand Neutroformer looking from the panel front. A lead is connected, however, from the tap of the second and third Neutroformers going directly to one terminal respectively of the second and third Neutrodon condenser.
The fixed condensers with capacities as shown on the wiring diagram are wired into position and need not be fastened either to the panel or base board, as the stiff No. 14 copper wire will hold them in position. After you have completed wiring up your receiver or preferably step by step as you fasten each wire in position check off with a heavy pencil on the wiring diagram the connection that you have just made. When the wiring is completed, all wires will have been checked and in addition by doing the job this way, you are doubly checking yourself for mistakes.
On the wiring diagram, no wire is shown jumping another one with a loop symbol. The plan shows each wire passing across the others and only connecting to cross wires when represented by a solid black dot. Check this carefully with your own wiring.
In the next article of this series, detailed instructions will be given for balancing out the inherent capacity of the vacuum tu&es as well as the stray-circuit capacities, thereby eliminating parasitic and distorting oscillations and regeneration.