US Buyers: Please Note

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  • No import taxes
  • No customs fees
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Green CRT Oscilloscope Tube 3LO1i 30mm / 1.3"

Made in USSR. New, Old Stock

Comes with the original matching tube socket included, making it ready for your DIY projects!

This high-quality Soviet-era 3LO1I (3ЛО1И) cathode-ray tube. Featuring a classic 33.5mm (1.3-inch) round screen with a vibrant green phosphor glow, it is a prized find for vintage electronics enthusiasts and DIY builders. It serves as an excellent component for ham radio projects and custom test equipment, and it is particularly popular for building unique, retro-futuristic oscilloscope clocks—including both digital displays and creative vector-graphic analog clock faces.

The base pinout diagram and full connection schematic can be found in the image gallery alongside the general views.

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Technical Data:

  • Filament voltage: 6.3 V
  • Filament current: 0.54 to 0.66 A
  • First anode voltage: 0 to 50 V
  • Second anode voltage: 500 V
  • Cutoff voltage: -90 to -30 V
  • Maximum screen diameter: 33.5 mm
  • Maximum tube length: 115 mm
  • Line Width (Center of Screen): max 0.4 mm
Maximum Ratings:
  • Filament voltage: 5.7 to 6.9 V
  • First anode voltage: 0 to 150 V
  • Second anode voltage: 500 to 800 V
  • Voltage between any plate and second anode: -450 to +450 V
  • Modulator circuit resistance: 1.5 MOhm
  • Heater to cathode voltage: -125 to 0 V
  • Grid Circuit Resistance: max 2 MOhm

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Shipping and Handing

Buyer pays fixed shipping costs including insurance for any country. Shipping costs for this item can be found in the section Shipping and Payments. This item will be shipped to you from Europe (Ukraine) by Registered Airmail after payment is received and verified.

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