Diff: 3M

Differences between current version and predecessor to the previous major change of 3M.

Other diffs: Previous Revision, Previous Author

current version

3M

Brochures

• Meet the Pro's Pro - Describes multitrack audio recorders.
• Professional Audio Recorder Scheduled Maintenance - Scheduled field maintenance provided by 3M. 2.8MB. Contributed by Gary Glaenzer

Manuals

• Series 79 multitrack audio tape recorder. 1973. Contributed by Gary Glaenzer. 6.5MB

• 350

  • Head Replacement - Mineapolis Magnetics instructions on head replacement for Ampex 300, 350, 400, 450, and 3100 series.
• Series 410 Professional Audio Recorder. Contributed by Gary Glaenzer. 141MB

• Series 500 Multitrack audio tape recorder (1970). Contributed by Gary Glaenzer.

  • Manual - 158MB.
  • Remote Control - M56 Functional Description, Using the 56017B100 Remote Box. 131kB
  • Preventative Maintenance and Alignment, 320kB
  • Suggested Preventative Maintenance Schedule, 450kB

Tutorials

• Fundamentals of Magnetic Recording. Contributed by Gary Glaenzer. 1.2MB

Technical Bulletins

• Technical Bulletins 1 - 34 - Includes replacement of Motorola FETs with Fairchild or National, improving lamp reliability, changing power supply current limit, modifying to get variable speed, modification to read SMPTE time code in fast forward and rewind, elimination of power off erase surge, elimination of possible sync oscillation, elimination of bias beating between multiple machines, modification to eliminate overdissipation in bias oscillator resistors, Dolby interface, conversion to accept 14 inch reels, fast forward and rewind mute improvement, improvement of record amplifier low frequency response, prevent high frequency amplifiers in the line amplifier,

  eliminate pop in adjacent track monitor when record started on another track, prevention of oscillation when Dolby unit disconnected, capstan motor replacement to eliminate bush noise, elimination of need to readjust bias on tape speed change, modification to mute electronics when tape is stopped, increase erase level to work around LDR resistance increase with aging, improvement of logic flip flops, preventing false trigger of end of tape sensor, bias and record level setting for various types of tape, prevention of echo on high level transient signals, change of mute timing for fast forward and rewind, improved audio performance through op amp replacement, allow head doors to remain closed when tape stopped, record punch in and out modification. Contributed by Gary Glaenzer. 23MB.

• Miscellaneous Technical Bulletins - Various modifications to professional recorders to improve performance. Contributed by Gary Glaenzer.
• Record and Bias Levels - Charts describe the maximum flux density for various 3M tapes and bias level for various tapes and head gaps. Contributed by Gary Glaenzer.
• Tape Recorder Alignment in 5 Easy Steps] - Contributed by Gary Glaenzer. 2.1MB

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