MAINTENANCE FOR AREARAE
6-5
4. Refer to Figures 6-2 and 6-3: Carefully unscrew the three
screws that hold down the gas plate to the analog PCB and
sensors. Remove the gas plate.
5. Identify the location of a specific toxic sensor and remove
the sensor by gently pulling the sensor upward.
6. Plug a new sensor into the empty sensor socket. Make
sure that black line on the sensor label is lined up with the
white marker on the PCB and the sensor pins are aligned
with the socket before pushing down the sensor.
7. Replace the gas plate and tighten the three screws to hold
down the sensors. Reconnect the battery pack. Replace
the monitor cover.
8. Turn AreaRAE on. The microprocessor automatically
recognizes the sensors installed and configure the monitor
accordingly.
NOTE:
The gamma radiation sensor installed in the
AreaRAE Gamma does not usually need to be replaced
unless it is damaged or malfunctioning. To replace the
gamma sensor, remove the dummy sensor plug from the
PCB and the gamma sensor module. Replace it with a new
module and reconnect the dummy sensor plug on the PCB.
Special Bias Voltage for Toxic Sensors
The NO and some NH
3
toxic sensors require a special 300 mV
bias voltage to operate. Only the first toxic sensor socket
provides such a special bias voltage. Therefore, NO or biased
NH
3
toxic sensors must be installed into the first toxic sensor
socket (Tox1) in AreaRAE-Gamma.
In addition, there is a DIP switch or pin jumper located on the
analog PCB next to the PID sensor. When an NO or biased
NH
3
toxic sensor is plugged into the first toxic sensor socket, it
is necessary to switch the jumper to the right to enable the bias
voltage. During the power-on sequence, the microprocessor
checks the sensor ID and the bias voltage. If the NO or biased
NH
3
sensor is plugged into the wrong toxic sensor socket or he
jumper is not switched on, an error message is displayed.