422
The Tektronix Type 422 is a 15 MHz portable dual-trace oscilloscope. It was available with an optional battery back for operation without mains power. Early versions use an 8056 Nuvistor tube for the front-end cathode follower. Later versions use a FET front end. The 422 uses tunnel diodes from triggering. The post-deflection acceleration voltage is 4900 Volts.