• Country
• United States of America (USA)

• Manufacturer / Brand
• Motorola Inc. (ex Galvin Mfg.Co. Chicago); Schaumburg (IL)

• Year
• 1951 ?

• Category
• Broadcast Receiver - or past WW2 Tuner

• Radiomuseum.org ID
• 48849

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

• Number of Tubes
• 4

• Valves / Tubes
• 1R5 1U4 1U5 3S4

• Main principle
• Superheterodyne (common); ZF/IF 455 kHz; 2 AF stage(s)

• Tuned circuits
• 6 AM circuit(s)

• Wave bands
• Broadcast only (MW).

• Power type and voltage
• Line / Batteries (any type) / AC/DC 117V = 110 -120 or 67.5 & D: 2 x 1.5 Volt

• Loudspeaker
• Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil) / Ø 3.5 inch = 8.9 cm

• Material
• Metal case

• from Radiomuseum.org
• Model: playmate Jr. 51M1U Ch= HS-283 - Motorola Inc. ex Galvin Mfg.Co

• Shape
• Portable set > 8 inch (also usable without mains)

• Dimensions (WHD)
• 7.5 x 5 x 4.5 inch / 191 x 127 x 114 mm

• Notes

• Motorola model 51M1U is a three power operated portable superheterodyne receiver with loop antenna. Selenium Rectifier ; Color=Green. Typo on first page in tube types , power output 354 has to be 3S4.

• Net weight (2.2 lb = 1 kg)
• 1.589 kg / 3 lb 8 oz (3.5 lb)

• External source of data
• Ernst Erb

• Circuit diagram reference
• Beitman Radio Diagrams Vol. 11, 1951

• Mentioned in
• Rider's Perpetual, Volume 22 = covering 1951

• Literature/Schematics (1)
• Photofact Folder, Howard W. SAMS (Set 149 folder 8 date 11-51)

• Other Models

• Here you find 4596 models, 2962 with images and 4095 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from Motorola Inc. (ex Galvin Mfg.Co. Chicago); Schaumburg (IL)