INDEX 



(Numbers refer to paragraphs) 



Alarm: 35 

 120B Amplifier: 



location: 4 



checking for self -noise: 11-13 



gain and output: 11 



frequency response? Fig 30 



tube complement: 12 

 L21A Amplifier 



location: 4 



self noise measurements: 7-10 



removing end plate: 8 



filters for: 14 



frequency response: Figs 6 29,36,3? 



gain and output: 15 



tube complement: 15 



servicing: 16-17 



gain check: 18 



power supply s ' 20-23 

 Amplifier Channels: 4-23 

 Automatic Switching Unit: 34-41 



location: 34 



operation: 34-38 



description: 34 



schematic: Fig, 46 



volume, control: 38 



sensitivity adjustments 39 



resetting: 40 



servicing: 41 



tube complement: 41 

 Biweekly Tests: 119 

 Bus Volume Control: 19,24 

 "Caltron": 81-85 

 Caution: 23 



Channel Amplifiers: 4-23 

 Channel Amplifier Power Supplies: 



20-23 

 Chronometer and Code Switch: 100~107 



location: 100 



function: 102-103 



coding switch: 104 



terminal strip: 105 

 . winding: 106-107 



servicing: 106-107 



booklet: 107 



Coding Switch: 104 

 Daily Tests: 119 

 Fuaes: 



location: 20,116 



for Time Tone Amplifier: 28 



AC for Rack 2: 28 



for Monitor Amplifier: 30 

 Graphic Level Recorders: 42-66 



location: 42 



schematic: Fig 47 



slow- and high-speed: 44 



operation: 46-48 



turning on and off: 45--47 



speed controls: 49-51 



inserting paper: 52 



protective relay: 53 



potentiometer: 54-55 



sensitivity PL recorder: 58 



switchbox and amplifier: 56-57 



checking: 59-61 



maintenance: 62-63 



basic operation: 64-66 



time indexing mechanism: 67-76 

 Headphone Monitor Amplifiers 25 

 Hydrophone Connections; 5-6 



terminal strip: 5 

 Initial Alignment: 2-3 

 Lever-action Switches s 6 

 Logging Tests: 120 

 Loudspeaker: 33 

 Magnetic Tape Recorders: 77-=99 



location: 77 



schematic - Mirrophone: Fig, 48 j 

 Caltron: Fig 49= 



operations 78-80, 86-93 



distinction between Mirrophone and 

 Caltron: 81-85 



recording time available: 87 



tuning eye: 89 



VTVM connection: 90 



frequency test: 92-93 



replacing pole pieces: 91,93 



tape repair: 94 



servicing: 96-99 



