Royal 500 Ch= 7XT40 Circuit #2 1st Production

Zenith Radio Corp.; Chicago, IL

  • Year
  • 1955/1956
perfect model
  • Category
  • Broadcast Receiver - or past WW2 Tuner
  • Radiomuseum.org ID
  • 268852
    • alternative name: Chicago Radio Lab

Click on the schematic thumbnail to request the schematic as a free document.

 Technical Specifications

  • Number of Transistors
  • 7
  • Main principle
  • Superheterodyne (common); ZF/IF 455 kHz; 2 AF stage(s)
  • Tuned circuits
  • 5 AM circuit(s)
  • Wave bands
  • Broadcast only (MW).
  • Power type and voltage
  • Dry Batteries / Batteries: "AA" 4 x 1.5 Volt
  • Loudspeaker
  • Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil) / Ø 2.75 inch = 7 cm
  • Power out
  • 0.1 W (0.18 W max.)
  • Material
  • Plastics (no bakelite or catalin)
  • from Radiomuseum.org
  • Model: Royal 500 Ch= 7XT40 Circuit #2 [1st Production] - Zenith Radio Corp.; Chicago,
  • Shape
  • Very small Portable or Pocket-Set (Handheld) < 8 inch.
  • Dimensions (WHD)
  • 3.5 x 5.75 x 1.5 inch / 89 x 146 x 38 mm
  • Notes
  • The Zenith Royal 500 is a battery operated 7 transistor portable BC band radio. The BC band frequency tuning range is 540-1600kHz. The first production run had 4 different chassis due to limited quantities of transistors from various manufacturers.  Chassis have chassis numbers along with a color code dot in battery compartment.

    Year Production
    Run
    Chassis
    Number
    Chassis
    Type
    Transistor
    Source
    Color Code
    Dot
    Cabinet
    Colors
    55/56 1 7XT40 Circuit 1 Hand Wired Sylvania Black R,Y
    55/56 1 7XT40 Circuit 2 Hand Wired Sylvania Maroon R,Y
    55/56 1 7XT40Z Hand Wired Raytheon Red R,Y
    55/56 1 7XT40Z1 Hand Wired Texas Instr. Green R,Y
    56/57 2 7XT40 Hand Wired Sylvania Magenta R,W,Y
    56/57 2 7XT40Z1 Hand Wired Texas Instr. Brown R,W,Y
    57/58 3 7ZT40 "Revised" PCB Sylvania Magenta L,R,V,W,Y
    57/58 3 7ZT40Z PCB Raytheon Orange L,R,V,W,Y

    The two 7XT40 chassis from the 1st production run are similar except use different transistors. See notes below for colors.

  • Net weight (2.2 lb = 1 kg)
  • 1 lb 3 oz (1.187 lb) / 0.539 kg
  • Price in first year of sale
  • 75.00 $
  • Literature/Schematics (1)
  • - - Manufacturers Literature (Zenith Service Manual "Royal 500" All transistor Portable Radio)
  Radio a transistor tascabili americane: Zenith Royal 500 “Owl Eyes” (Per cortesia di L.Salvatore/ARM) 3327 KB
  • Documents regarding this model
  • Author
  • Model page created by John Kusching. See "Data change" for further contributors.

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