9/15/06
888-2586-001
4-67
WARNING: Disconnect primary power prior to servicing.
Section 4 Overall System Theory
Platinum Z16HD+
5 will be low and the REM_ON_LOW(BAR) command is inhibited. When Life
Support Mode is initiated, U32-5 and therefore U26-5 is forced high enabling the
REM_ON_LOW(BAR) command.
c.
MASTER_NORMAL(BAR) applies a high to the CLEAR line of U8-3. This
enables U8-6, the Q output, to apply a 3 second SOFTSTART_MUTE after a
power failure. The POWERFAIL(BAR) signal comes from U37-7 and is a mini-
mum 200mSec low pulse. U37 is monitoring the +20Vdc supply and will bring
pin 7 low if the voltage drops below approxi20Vdc. Note that the POW-
ERFAIL(BAR) signal will not go back to the high condition until 200mSec after
power is restored. In Life Support Mode, after a power failure U37-7 will go high
which triggers U8-4. This will then trigger a SOFTSTART_MUTE via OR gate
U33-10 for 3 seconds. The SOFTSTART_MUTE signal mutes the exciter RF out-
put, to make sure there is no RF applied to the system for 3 - 5 seconds to allow
the supplies to fully charge. U8 is only active in Life Support Mode. It is cleared
by the MASTER_NORMAL(BAR) signal when the Master Controller is opera-
tional. The Master Controller normally takes care of this function via the
SYSTEM_MUTE line.
d.
MASTER_NORMAL(BAR) applies a high to the CLEAR line of U8-13. This
enables U8-10, the Q output, to apply a 3 second SOFTSTART_MUTE whenever
an on command is given via U35-11. The SOFTSTART_MUTE mutes the exciter
RF output, to make sure there is no RF applied to the system for 3 - 5 seconds to
allow the supplies to fully charge. U8 is only active in Life Support Mode. It is
cleared by the MASTER_NORMAL(BAR) signal when the Master Controller is
operational. The Master Controller normally takes care of this function via the
SYSTEM_MUTE line.
e.
MASTER_NORMAL(BAR) applies a high to OR gate U31-5. This circuit is not
used.
f.
MASTER_NORMAL(BAR) applies a high to OR gate U31-2. This enables the
FAILSAFE command by placing a high at U25-5, when in Life Support Mode.
4.8.7.2.2 Reflected Power
The reflected power sample enters the board at J3. It is detected by CR10 and buffered
by U1-1. The voltage at TP7 is directly proportional to the amount of reflected power
coming back to the transmitter from the antenna or transmission line. This DC sample
voltage is sent to the Master Controller, via J1-A19, for VSWR protection and
monitoring when the Master Controller is operational.
If the Master is not functioning (Life Support Mode), then the RFL PWR Overload
Adjust, R24 and comparator U3-2, will protect the transmitter from excessive VSWR
by shutting it off. R24 sets the reference voltage for U3-5, which is the VSWR
comparator for Life Support Mode. If the VSWR exceeds the factory set value in this
mode the comparator will trip and U3-2 will go low. This is inverted at U7-6 and
becomes, LS_SYST_FAULT, which stands for Life Support System Fault. This signal
Содержание Platinum Z16HD+
Страница 4: ...MRH 2 888 2586 001 9 15 06 WARNING Disconnect primary power prior to servicing ...
Страница 6: ...9 15 06 888 2586 001 MRH 1 WARNING Disconnect primary power prior to servicing ...
Страница 8: ...viii 888 2586 001 9 15 06 WARNING Disconnect primary power prior to servicing ...
Страница 10: ...x 888 2586 001 9 15 06 WARNING Disconnect primary power prior to servicing ...