Radio age (Jan 1927-Jan 1928)

RADIO AGE for November, 1927 ■ *^ -■* - *» «* ■ *i':: *♦ T >'* *' * HL ^ G, j ^'~ ': -"_'-• % " 1 I-*'A -A ^ r4' £ * * ? p*-^ ,_^_ '^jp^'-^» 4 p< 1 1, . 1 t i I f 1 1 % y * p « » 1 ^^Sw^wwww Figure 3 — Rear panel view of the Aero-Seven. trically without defects. If, however, regardless of the above instructions, the choke is taken apart, be careful of the very fine wire in putting it together again. If, in the latter event, your set fails to function, you have broken the very fine wire in this choke. In which case, you should have it repaired or purchase a new one. In the assembly of the receiver the subpanel is the best starting point, as most of the work may be done on it without putting on the front panel, thus allowing the work to progress unhampered. Looking at Figure 3, we see the back of the assembly. The first radio frequency tube socket is partially hidden behind the first radio frequency coil, but is mounted with one screw so that the grid and plate terminals are nearest the first Aero coil. Across the back of the panel are mounted the second two radio frequency tube sockets in the same direction as the one previous. This places the grid and plate connections closest to the points to which they are to connect. Next, closer to the front panel side and in succession, are mounted the Amsco cushion detector socket and the three audio sockets. If these latter are mounted with the grid and plate terminals toward the binding post holes and the Amsco resistor couplers directly behind, a practically direct connection is secured to the plate and grid terminals. In the blank space in front of the radio frequency coils and sockets is mounted the Amsco triplet condenser. Four brackets are supplied with this condenser, which may be secured by carefully removing the nuts at the corner bracing rods, one at a time, and placing the long side of the bracket over the stud and replacing the nut firmly. The brackets should be mounted on the side opposite the small adjustment condensers, so that in mounting these adjustments will be perfectly accessible. The condenser is then bolted down to the subpanel with the shaft extending near the center of the receiver. The panel brackets should now be put on so as to support the subpanel while working. All the minor accessories, such as binding posts, condensers, etc., may now be put on before the receiver is wired. These accessories are better shown in the List of Aero-Seven Parts List Price 1 A e r o-Seven Founda tion Unit: consists of drilled and engraved front panel, 7x24x}s> drilled subpanel, 7x23 x3/16; two Aero sub panel brackets and ac tual size blue print $12.00 1 Aero TRF Kit, Code U-12 (3 coils) 12.00 1 Aero Choke No-Skip No. 60 1.50 1 Silver-Marshall Drum Dial 3.00 1 Carter Battery Switch D .65 1 Carter 200-ohm "IMP" Potentiometer 1.25 1 Carter 6-ohm "IMP" rheostat 1.00 1 Carter H-1000 Resis tor .30 1 Carter H-l Resistor... .25 1 Carter .00025 Mfd. Condenser with Clips.. .50 1 Carter .001 Mfd. Con denser .50 2 Carter V2 Mfd. Bypass Condensers 1.80 10 X-L Binding Posts, L e t t e r e d = Aerial, Ground A + , A — , 2C — , B90 + , Ampli fier, B + , Speaker + , Speaker — 1.50 1 Amsco Floating Sock et 1.00 6 Amsco Plain Sockets @ $0.50 3.00 1 Amsco .0005 Mfd. Tri ple Condenser 11.25 1 Amsco Grid Gate Mounting .30 1 Amsco 5 Meg. Grid Gate .50 1 Kit AMSCO Aero-7 Resistance Coupled Audio 7.00 Screw Assortment and Bus Bar .25 List ! >59.55 bottom view, Figure 4. Holes are provided for all these fittings and in some cases holes which were used to hold objects to the top of the panel are used for one or both ends of another object on the bottom. Looking at Figure 3, we have from right to left, the 1,000-ohm Carter resistor used in the antenna input circuit, the Carter y2-mi. bypass used across the potentiometer, another across the 90-volt B supply, the Amsco resistor mounting with grid leak, the .001 bypass across the plate and filament of the detector tube, and the Carter 1-ohm resistor for the "A" circuit. After all these have been mounted the subpanel is ready to wire in accordance with the circuit diagram, Figure 2. The wiring is so simple that most of it can be followed out from the photographs. It should be noted that in most cases where a circuit is to pass through the subpanel that a hole has been provided in the drilling of the foundation unit, and where no hole is provided the lead is intended to pass through the panel by use of the nearest mounting screw of that piece of apparatus. The bracket from the Silver-Marshall drum dial should now be mounted under single hole mount nut of the condenser and the front panel prepared. The dial plate should be mounted on the panel with the Carter 200-ohm potentiometer at the left, the rheostat at the right, and the battery switch below, the connection screws of both pointing downward. This done, the panel may be screwed to the assembly by means of the panel bracket holes and the holes in the drum dial bracket. Care should be taken that the shaft and collar assembly of the drum dial are in place before putting on the panel. Now, by putting on the drum and with a screw driver inserted in the lips of the shaft mechanism the drum may be slid along the condenser shaft and into the aperture of the drive shaft and released. At the same time the dial should read 100 degrees with the condenser plates full in and the set screw is then locked on the condenser shaft. The remainder of the wiring to the potentiometer and rheostat may now be completed and the receiver is ready to -set up. (Continued on page 28)