1956 Zenith Royal 500, 7XT40Z1 chassis
Coat pocket radio, nylon cabinet
5 3/4 x 3 1/2 x 1 1/2 inches / 146 x 89 x 38 mm
Seven transistors (Zenith ovals, 121-15, 121-16, 2x 121-17, 121-18, 2x 121-19)
Superheterodyne circuit, hand-wired aluminum chassis
Four 1.5-volt AA cells
Manufactured by Zenith Radio Corp.; Chicago, Illinois
Zenith's first transistor radio — the unit shown here is the third chassis version (7XT40Z1) of the first Royal 500 model series, preceded by the 7XT40Z chassis, and before that the original 7XT40 chassis of the very first Zenith 500 version produced in 1955. All three versions had hand-wired chassis, unlike their successors which used pc-board chassis. And unlike their many successors, beginning with the 1957 7ZT40 chassis series, the first three Royal 500 versions lacked vernier tuning.
All these versions shared a nylon cabinet, a material not used all that often for transistor radio cabinets -- the vast majority of transistor radio cabinets were made of ABS, a version of polystyrene that was much less brittle than plain polystyrene but still far more susceptible to cracks, chips and scratches than was nylon. Zenith's "UNBREAKABLE NYLON" stamp found on the back face of all 500 cabinets clearly was a claim that went too far: some small percentage of cabinets today can be found cracked or chipped -- yet to this day, many nylon radio cabinets are not only free of damage but have retained that wonderfully glossy "like new" finish that few ABS cabinets have managed to hold onto without restoration.
Along with the Regency TR-1, the Zenith Royal 500 is a US transistor radio that no one is about to forget anytime soon.