Download schematics for the 737 AC Model. Serial No 6502 and up.
Download schematics for the 737 DC Model.
Selector
RF Amplifier
Power converter
Speaker
Tubes
Service Notes
The chassis of the DC versions are all the same. The AC versions have two different possible chassis. Chassis with serial numbers 6502 and higher use a slightly different version of the power convertor unit, which incorporates a different power transformer, and several additional resistors. These later production 737s probably utilized left over power transformers from another Sparton radio model, the resistors have been added to the circuit to compensate for the differences. Other than the power converter differences, high and low serial number Model 737 AC Equasonnes are identical. The low serial number 737 chassis is identical to that found in AC Models 600, 610 and 620.
The AC version is an 10 tube radio.
The RF amplifier unit of the 737 is of the 931 type and is common to virtually all Equasonne models.
The selector unit is of the type which houses an additional 484 tube, and is common to most Equasonne models.