HP 00424-90026 Model 424A Crystal Detectors Operating Note Manual.

HP 01914-7 1967 Model 424A Crystal Detectors Operating Note Manual.

HP 00424-90026 1969 Model 424A Crystal Detectors Operating Note Manual.

HP 1821A Time Base And Delay Generator Operating And Service Manual 1967

HP 914A 914B Moving Loads Operating Note 1967

Original HP 427A Voltmeter operating and service manual 01791-2 July 1967

Agilent HP Keysight 00424-920 - 424A Operating Note

HP 16048C Test Leads Operating Note 16048-90020