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The Factory or Authorized Service Facility may repair or replace the module.
No re-calibration is necessary; however, the Gauge calibration is stored in a
memory module that must stay with the same Gauge or re-calibration will be
necessary.
6.3.2 Base Plane Board (200768)
This board, into which all of the small modules are plugged, has no active
components, only interconnects between other components. The probability
of failure is very low except for physical damage. Should it become
necessary to replace it, some soldering is required so either the entire Base
Frame must be replaced, or returned, or the entire Gauge returned. No re-
calibration is required.
For protection a circuit breaker is above the battery holders which will open
up if the main power circuits become shorted. A red indicator is visible when
the circuit breaker is closed and applying power to the board.
The base board also has a push-button switch in the upper center of the
board which is used to discharge the high voltage before servicing any
of these circuits. This button should be pushed and held for about one
second before removing or replacing the High Voltage, Density, or Moisture
Modules.
The entire frame, including the detectors, is removed by means of the seven
screws around the edge of the frame. Do not remove the screws, which
attach the Board to the frame.
6.3.3 High Voltage Power Supply Module (200088)
This module supplies a highly regulated 900 vdc to the Density and
Moisture Amplifier modules and in turn to the detectors. From unit to unit,
the voltage may vary ±25 volts but once established, it is very stable.
This voltage can cause a severe shock and before any replacement is
attempted, the discharge push-button switch located in the center of the
base circuit board must be pushed and held for about one second.
The module is easily replaced by removing the screw located in the middle
of the module. When plugging in another one, look and at the pins closely
and orient the module pins to the circuit board sockets. If they are aligned
the module can be inserted easily. Do not apply force as the pins may be
bent or damaged.
The module is not repairable, and must be replaced if defective. The
replacement does not affect calibration.
6.3.4 Density Amplifier Module (200087)
This module is used to condition varying amplitude pulses from the two
gamma detectors to logic level pulses for the counter in the processor
module.
There are two adjustments, which control the amplitude of the pulses from
