Andrejasich Talks About Material and Cost Reductions
In the early days of Zenith radio design there was only minor competition. As foreign makers came more numerous, cost became more of an issue, especially when the radios were assembled in the United States.
Several implementations in circuitry reduced the number of components that were hand inserted in production. When silicon transistors replaced the old temperature sensitive germanium devices, voltage biasing was replaced with current biasing. This reduced the parts count by two resistors and one capacitor for each RF device.
The push-pull transformer coupled audio stages were replaced by a complementary-symmetry audio circuit, eliminating the costly interstage and output transformers.
Engineering worked with a ceramic capacitor manufacturer to develop what we called INTEGNETS (Integrated Networks). Using a ceramic substrate the manufacturer placed resistors and capacitors on the ceramic and brought out leads. This reduced component count for hand insertion and gave us also more PC board space. Looking at the schematic of the Royal 59, for example, you can see the RC networks within the dotted lines.
Several innovations by foreign manufacturers were included in later sets. The air gang (tuning) was replaced by a solid dielectric variable capacitor manufactured by Mitsumi. Instead of a die cast, chrome plated front escutcheon, hot stamping was used. This applied a metallic foil by heat to highlight parts of the cabinet front. Later, Panasonic, (Matsushita) developed a process whereby plastic could be electroplated.
The IF coils (1/2 and 3/8 inch square were made locally,but the smaller 1/4 inch square units were made by Toko). The smaller size made for smaller receivers.
The major and inevitable cost reduction (labor) was to move our manufacturing overseas. For a number of years, we manufactured our radios in a company called Transelectronics in Hong Kong. Following the low cost labor, we went to Japan, then Taiwan and finally Korea. In all cases, we controlled the radio design, both electrically and aesthetically. Zenith Quality Control personnel were present to monitor pilot runs and start of production. If any of our written electrical or physical specs were not met, a rework line was set up to correct any problems. Afterwards all shipments had to pass a QC audit before they could be released for shipment to the USA.
Here are IF transformers from a Royal 200, a Royal 500 and a Royal 500H. The small unit from the Royal 500H is encased in an additional metal shield.
Although Mr. Andrejasich spent many years at Zenith dedicated to transistor radio development, he spends his retirement enjoying the restoration of antique tube radios such as the one below.