The 7788  (European: E810F) (Russian: 6Ж52П (similar)) (P/N 154-0420-00) is a long life, shock and vibration resistant pentode vacuum tube with a B9A (Noval) miniature 9-pin base.

7788 Tube

It is used as the output tube in the vertical power amplifier of the 581A/585A.

Links

Some instruments using part 7788

Instrument Manufacturer Class Model Description Introduced
529 Tektronix Audio/Video 529 TV Waveform Monitor 1965
545B Tektronix Oscilloscope 545B 30 (33) MHz oscilloscope 1964
581A Tektronix Oscilloscope 581A 85 MHz oscilloscope 1963
585A Tektronix Oscilloscope 585 85 MHz oscilloscope 1963
Telequipment D56 Telequipment Oscilloscope D56 15 MHz 2-ch scope (?)