• Country
• United States of America (USA)

• Manufacturer / Brand
• Zenith Radio Corp.; Chicago, IL

• Year
• 1962

• Category
• Broadcast Receiver - or past WW2 Tuner

• Radiomuseum.org ID
• 267987

• • alternative name: Chicago Radio Lab

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

• Number of Transistors
• 7

• Semiconductors
• 2N411 2N409 2N409 2N409 2N407 2N407 2N407 1N87G

• 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 / 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 275-B Ch= 7CT40Z7 - Zenith Radio Corp.; Chicago,

• Shape
• Very small Portable or Pocket-Set (Handheld) < 8 inch.

• Dimensions (WHD)
• 146 x 95 x 44 mm / 5.7 x 3.7 x 1.7 inch

• Notes

• The Zenith Royal 275-B is a battery operated 7 transistor portable BC band receiver.  The BC band frequency tuning range is 540-1600kHz.  Has push-pull output stage and earphone jack that disconnects the speaker for private listening.

  This model uses chassis 7CT40Z7.  Earlier Royal 275 models used chassis 7CT40Z1 followed by chassis 7CT40Z2.

  The Royal 275 radio was available with 4 different cabinet colors:

  Model	Cabinet Colors
  Royal 275-B	Dark blue with light blue back
  Royal 275-F	Dark green with light green back
  Royal 275-J	Brown with tan back
  Royal 275-Y	Black with beige back

  NOTE: The Zenith Supplementary Service Manual Model Royal 275 Radio Chassis 7CT4027, dated 9-62 lists the chassis as 7CT4027 in the title, which is not correct.  The chassis is correctly listed as 7CT40Z7 in the table (Which follows the Zenith Chassis numbering system), and this has been confirmed with chassis numbers listed on the label inside actual radio models.

• Net weight (2.2 lb = 1 kg)
• 0.520 kg / 1 lb 2.3 oz (1.145 lb)

• Literature/Schematics (1)
• - - Manufacturers Literature (Zenith Supplementary Service Manual Model Royal 275 Radio Chassis 7CT4027 dated 9-62)

• Literature/Schematics (2)
• - - Manufacturers Literature (Zenith Service Manual Model "Royal 275" Transistor Portable Radio dated 5-26-59)

• Author
• Model page created by John Kusching. See "Data change" for further contributors.

• Other Models

• Here you find 4496 models, 4101 with images and 3615 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from Zenith Radio Corp.; Chicago, IL