Zenith Royal 500, called "owl
eyes", was manufactured in many versions which differs in the
chassis model and in the case shape.
first version ďAĒ (chassis 7XT40)
has 7 transistor, doesnít have the printed circuit board
and itís hand-wired; It
differs from the other versions by
the bars that extend across the volume and tuning knobs and the tuning control is direct made, the knob operates in
the variable capacitor shaft.
The B version (chassis 7ZT40),
made in 1957, has the printed circuit board and a vernier tuning
In 1958/59 was manufactured the D
version (chassis 8AT40)
which has an extra transistor added to improve reception.
In 1972 Royal 500 was entirely restyled
(H version) later manufactured an L version.