4-8
888-2406-002
WARNING: Disconnect primary power prior to servicing.
Overall System Theory
4.3.3.3 IPA Monitoring
The IPA Backplane Board provides for monitoring and/or interfacing of 4 main IPA
parameters:
•
IPA temperature (VTEMP_IPA1 and/or VTEMP_IPA2). If the IPA board exceeds
100°C, the controller will mute the transmitter and/or switch to the alternate IPA.
The sensor is actually located on the IPA board, but is interfaced through the
Backplane.
•
IPA supply voltage (Vd_IPA_SAMPLE). A monitoring sample is sent to the con-
troller through fuse F2. The Supply voltage for the IPA is diode or’ed from both
PA supplies for redundancy.
•
IPA current (Id_IPA). IPA current is measured by measuring the voltage drop
across the series resistor R1. IPA current fault threshold is set at 14.3 amps.
•
IPA Forward Power (IPA FWD PWR). A sample of the IPA forward power is
taken by the directional coupler (shown right after K3 on the schematic) and
detected by CR1. The DC voltage at TP1 will therefore be relative to the IPA out-
put. This is also sent to the controller for monitoring and main/alternate IPA
switching.
4.3.3.4 Air flow sensing.
Airflow is sensed as the difference in temperature between a heated sensor, RT1,
and an ambient sensor, RT2. RT1 is actively biased via R3 which will cause a steady
increase in temperature with no air flow. Under normal operation, the voltage
difference between the two sensor outputs will stabilize at some value depending on
the amount of air flow. If the airflow is reduced or non-existent, then RT1 will heat
up increasing its voltage output, whereas RT2 will stay the same. Eventually the
voltage difference between the two sensors will reach a threshold where the
controller will turn the fan to high speed to compensate for the reduced airflow. If
the airflow is still insufficient, the transmitter will be shut off.
4.3.3.5 IPA_1 and IPA_2 interlocking.
The signals IPA1_PCB_OK and IPA2_PCB_OK are the interlock signals for the
IPA boards. The interlock connections on the IPA board (and the PAs as well) are
shorter than the other pins. This causes the interlock connection to break before the
RF and voltage contacts when the module is unplugged. This gives the controller
time to shut off the IPAs (via the IPA gate voltage, IPA1_GATE) so that the
connector contacts do not arc. However, it is not recommended that the IPA be
removed without shutting the transmitter off first.
Summary of Contents for Platinum Z2 CD
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Page 70: ...3 14 888 2406 002 WARNING Disconnect primary power prior to servicing Operator Guide ...
Page 130: ...4 60 888 2406 002 WARNING Disconnect primary power prior to servicing Overall System Theory ...
Page 194: ...6 38 888 2406 002 WARNING Disconnect primary power prior to servicing Troubleshooting ...
Page 196: ...7 2 888 2406 002 WARNING Disconnect primary power prior to servicing Parts List ...