WIRING DIAGRAM OF MODEL 38 A 2nd A.F. filament. shunt resistance is used before Serial No. 1,752,000 and the green-yellow tracer cable lead is not used. Connections for this resistance are shown in dotted lines in the diagram on page 71. Note that the black and the red cable leads feed the R.F. filaments 20 well as the 1st A.F. filament. A schematic diagram of the volume control is shown in Fig. 60.

WIRING DIAGRAM OF MODEL 37, (A and A.F. filament shunt resistance is used before Serial No. 1,385,000, in which Cte speaker post No. 2 connects to the centre-tap of this resistance, and the green-yellow tracer lead is not used. The R.F. plate circuit resistance is used after Serial No. 1,385,000. Note that the red and the black cable leads feed the R.F filaments as well as the 1st AF filament,

ATWATER KENT - Models 37-38
Line Voltage 115 - On Early Models "B" and "C" Voltages Are Lower Than Shown

SKETCH SHOWING CONNECTIONS FROM R.F.
TRANSFORMERS

WIRING DIAGRAM OF MODEL 38. A 2nd.A.F. filament-shunt resistor is used before Serial No. 1,752,000 and the green-yellow tracer cable lead is not used. Connections for this resistor are shown in dotted lines in the diagram on page 61. A schematic diagram of the volume control is shown in Fig. 78.

WIRING DIAGRAM OF MODEL 37,37 - F, 37 - C.
A 2nd - A F. filament shunt resistor is used before Serial No. 1,385,000, in which case speaker post No. 2 connects to the centre-tap of this resistor, and the green-yellow tracer lead is not used. The R.F. plate circuit resistor is used aiter Serial No. 1,385,000. 1n Model 37 - C the on-off switch is connected to the two terminals on either side of the ground eyelet. A 2nd - A, F. filament shunt resistor is used in the chassis of all Model 37.C receivers.

DIAGRAM OF POWER UNIT IN MODELS 37 AND 38 The diagram of the power unit in Models 40, 42,44 and 52 is similar to that shown above with the following exceptions: A regulating resistance is connected in series with the primary circuit in Models 42,44 and 52. A filter condenser is connected between F1 and ground. The junction point of the bias resistance is connected to the lower Instead of the upper ground cyclet.

SHOWINC CONNECTIONS FROM TRANSFORMER AND CONDENSER - CHOKE ASSEMBLIES TO PANEL ASSEMBLY This view shows the approximate position of leads from the metal containers. In replacement condenser-choke assemblies for Model 88 the lead to + B first A.F. terminal is sometimes black-red tracer instead of white.

DETECTOR AND Two STAGE AUDIO FREQUENCY AMPLIFYING CIRCUIT USED IN LATER MODEL 36,
AND IN MODELS 37, 38, 40, 42,44 AND 52

The 2nd A, F. filament shunt resistance (shown in dotted lines) is used in all Model 36 sets and in many Models 37 and 38. In later Models 37 and 88, and in Models 40, 42,44 and 52, this resistance is not used in the set, but the 2nd A.F. filament shunt resistance in the power unit is used for the same purpose a green-yellow tracer lead connecting speaker post No. 2 to the centre tap of the 2nd A.F. filament shunt resistance in the power unit. In Model 36, and in Model 37 console sets, the two terminals on either side of the ground eyelet are used for toggle switch connection in the 110 volt line. Insome Model 36 sets a green-yellow tracer lead is used instead of a black-red tracer lead for connection to the yellow lead of the 2nd A, F.T. The R.F. plate circuit resistance is not used in Model 86 nor in some 37 and 38 sets. Except for these minor variations, this circuit is standard in these sets, and the service man should remember the color scheme of A.F. transformers and the colors of cable leads and their location on the connection panel.