SECTION VII
MAINTENANCE
21.
General
The Surveying Altimeter is a precision instrument with the dial individually calibrated for its particular mechanism.
The dial and mechanism of each altimeter are matched parts, marked with a serial number, and are not interchangeable.
Therefore, field maintenance is limited to the adjustments and procedures described below.
22.
Calibration of the altimeter is restricted to setting pointer to agree with the desired reference. To set the pointer,
remove the bezel ring and plastic window as described in paragraph 25, and, using a screwdriver, slowly turn the adjusting
screw (6, fig. 2). The maximum extent of the adjustment is approximately +50 meters.
Caution: Do not turn the adjusting screw beyond the limits (red lines) marked on the dial.
23.
Renewing the Desiccant
When the desiccant indicator in the dial turns pink, the silica gel must be removed, and dried or replaced with
fresh desiccant. Unscrew the cap (5, fig. 3) in the side of the case and remove the desiccant from the tube. Replace in
the reverse order.
37