Super manual it contains all the things you need to service your Marantz 2100.
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3-12.
Model 10811A/B Find the line on Table 3-1 corresponding to the oscillator's aging rate. Then find the maximum allowable error (accuracy) on the horizontal axis. Follow the maximum allowable error vertically until it crosses the oscillator's known aging rate. Move horizontally to the left and read the minimum calibration interval in days. maximum allowable error known aging rate (per day) = calibration interval in days
Example: 5 x 10-9 (maximum allowable error) 3 x 10-10/day (known aging rate) 3-13. 3-14. = 16.67 days (~17 days) 3 X 10-10/day (known aging rate)
From Table 3-1, the oscillator should be adjusted approximately every 17 days. The minimum calibration interval may also be determined from the following formula:
