9/15/06
888-2586-001
4-53
WARNING: Disconnect primary power prior to servicing.
Section 4 Overall System Theory
Platinum Z16HD+
•
PA ISO Resistor Temperatures - VTEMP PA1 through VTEMP PA8 -Each ISO resis-
tor has a thermistor, used as a temperature sensor, attached to it for metering and fault
monitoring. To check the ISO resistor temperatures press [METERING, D, D then
selecting the desired Z-Plane]. A rise in the ISO resistor temperature indicates an
imbalance in the phase or amplitude of a PA output.
NOTE:
The temperature of the different PA ISO resistors (A1-A8 and B1-B8) can vary
quite a bit, but are considered okay if they are under A 75°C.
Az, Bz, Cz and Dz which also show up in these screens, are the temperature indications
for the ISO loads which are part of the 2 way combiner on each Z-Planes Isolation
board. A rise in this temperature would indicate an imbalance between the outputs of
the two foursomes on that Z Plane. ISO_AB or ISO_CD is the temperature of the reject
load on the 3dB hybrid which combines the outputs of two Z Planes.
4.8.5.4
Crossover (XOVER) Protection
Each PA Controller has what is called a Watchdog Timer. The outputs of the watchdog
timers are each monitored by the other PA Controller. If the pulses from the watchdog
timer are interrupted, due to either hardware or software problem, the other PA
Controller will initiate what is called a Crossover (or XOVER). Basically, an
operational PA Controller will apply a mute to all of the PAs associated with the
defective PA Controller, and switch them out of circuit before releasing the mute on its
own PAs. Maximum power output with one PA Controller out is approximately 33% of
nominal.
4.8.5.5
PA Controller Faults
For a complete listing of all of the faults associated with the PA Controller Boards refer
to Section VI, Troubleshooting.
4.8.6
Power Supply Controller Boards
There are 2 PS Controller Boards in the standard Z16HD+ transmitter. Each one is
capable of controlling two of the four Z16HD+ power supplies completely independent
one from another. This allows one of the supplies to have a critical failure and be shut
off without interrupting the operation of the other three.
The PS Controller functions include the following:
•
Control of the tap switching which is used to coarsely regulate the power supply volt-
age to 52Vdc.
•
Control of the Soft-Start and PA Power Supply Discharge functions.
Summary of Contents for Platinum Z16HD+
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