888-2406-002
4-45
WARNING: Disconnect primary power prior to servicing.
Overall System Theory
sequence will be aborted. After 3 (or 6) seconds, if the voltage is within tolerance,
the PS Controller will activate the lowest available voltage tap by activating one of
the four DRIVER signals. Since DRIVER_1 is connected to the 48V tap, it will be
activated first (if available) and the power supplies will come up to full charge.
The PS Controller will now check the power supply voltages via the DC Voltage
Samples from each power supply. These come into the board at J1 and J2, pins 13
and 14 from the rectifier boards. These signals pass through U7 which acts as a
linear amplifier and buffer to prevent the analog samples from overloading the front
end of the A/D converter in the microcontroller IC, U6. Using these samples the PS
Controller will determine when and if it is necessary to change taps to increase or
decrease the DC PA voltage. It will try to maintain the voltage as close as possible
to 52Vdc.
4.7.5.2 PA Power Supply Discharge
When the PS_DISABLE signal goes high, all of the SCR taps are disabled and the
DISCHARGE signals at J1-7 and J2-7 go low. This activates the PA Power Supply
Discharge circuit, which allows a quick and safe discharge of the PA supply.
4.7.5.3 Power Supply Standby Mode
Under certain circumstances, such as RF Mute, the power supplies will be placed in
standby mode via the signal PS_STANDBY. This signal comes from the Master and
PA Controllers. PS_STANDBY shuts off all the DRIVER signals which deactivates
all of the SCR taps on the power supply. However, it does not activate the discharge
circuit. This allows the filter capacitors to maintain charge and be ready to supply
power at a moments notice without having to go through the Soft-Start sequence
again. However, the capacitors will bleed down slowly if the standby mode is
maintained. To keep the voltage within reasonable limits, the PS Controller will
activate the Soft-Start circuit if the PA voltage drops below 42Vdc and shuts it off
when the voltage is above 52Vdc. The PS Controller will maintain charge in this
manner until the PS_STANDBY signal goes low, and the power supply is fully
active again or shut off by the PS_DISABLE signal.
4.7.5.4 Discharge Protection Circuit
The discharge protection circuit protects the power supply and the discharge circuit
components from a failure in the discharge circuit. Specifically it protects against a
short which would cause the discharge resistor to be “In circuit” when the power
supply is activated.
Summary of Contents for Platinum Z2 CD
Page 4: ...888 2406 002 WARNING Disconnect primary power prior to servicing ...
Page 6: ...888 2406 002 WARNING Disconnect primary power prior to servicing ...
Page 8: ...888 2406 002 WARNING Disconnect primary power prior to servicing ...
Page 10: ...888 2406 002 WARNING Disconnect primary power prior to servicing ...
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 ...
