TM 9-1829A, April 1944
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2021-07-07
If instrument is too fast at high speeds, either the magnet must be weakened with the magnet regulator (fig.
102) or the hair spring tension increased. Fasten face dial in position, start pointer on staff at about one-half
dial reading, and press it on as it is turned to zero. Check instrument at all speeds and refine calibration to
within limits below by moving hair spring regulator (fig. 83) or by moving the magnet regulator as follows:
Remove hole plug at back of case, using adjusting kit (T-178715) to catch on magnet regulator. Place key in
square hole in magnet shaft and turn magnet clockwise to increase, and counterclockwise to decrease speed
of the instrument (fig. 102). Replace regulator hole plug. If instrument cannot be calibrated, refer to paragraph
4.
Master reading
Calibration tolerance
10 mph
9-11 mph
30 mph
30-32 mph
60 mph
60-63 mph
j.
Replace bezel, gaskets, glass, etc.:
Refer to paragraph 31 n.