10 000 WATT FM BROADCAST TRANSMITTER
FM10
Page 6-9
15 November 1999
indications for remote metering,
B+ VOLTS SAMPLE
(TB1-16) and
TOTAL CUR SAMPLE
(TB1-17) which
provide final amplifier DC voltage and current level
indications for remote metering. Digital status
outputs, when active, provide current sinks to ground
which will sink current from an external positive
supply. When inactive, these status outputs are high
impedance. The
IPA/RF FAIL
(TB2-1),
PA/SUPPLY
FAIL
(TB2-2),
HIGH REFLECTED POWER
(TB2-3),
AC FAULT
(TB2-4),
HIGH TEMP
(TB2-5),
PA
VDC/COMBINER
(TB2-6),
INTERLOCK
(TB2-7),
FAN
FAIL
(TB2-8),
RF ON STATUS
(TB2-9),
XMTR
READY
(TB2-10),
REMOTE STATUS
(TB2-11) and
LOW BATTERY ALARM
(TB2-17) outputs are all
driven by the control/monitor PWB.
6.5.2.3
Local/Remote Control Selection:
See
figures SD-9 and SD-10. The local/remote control
status is selected by momentarily pressing either the
LOCAL CONTROL
switch (A13A1S4) for local
control of the transmitter or the
REMOTE CONTROL
switch (A13A1S5) for remote control of the
transmitter. When remote control is selected, the
local inputs have no influence with the exception of
the
RF OFF
switch (A13A1S7), which is always
active. This feature permits the RF power stages to
be turned off locally in the event of an emergency.
6.5.2.4
RF On/Off Control:
See figures SD-9
and SD-10. The transmitter's RF power stage is
controlled locally by
RF ON
and
RF OFF
switches and
remotely by the
REMOTE RF ON
(+) (-) and
REMOTE
RF OFF
(+) (-) control inputs. The
RF ON
switch is
disabled when the
REMOTE CONTROL
switch has
been pressed and the remote RF on and remote RF
off controls are disabled when the
LOCAL CONTROL
switch has been pressed. The
RF OFF
switch is
enabled in
RF ON
both local and remote control.
When the condition is enabled (locally or remotely),
the exciter interlock changes state to enable the
exciter, the
RF ON
indicator LED is turned on, the
remote RF on status is enabled (current sink), J6-6
will switch to 5 VDC (
RF On
) causing the low
voltage power supply to supply 24 VDC to the
cooling fans and the inhibit will be removed from the
IPA Volts Control
output (J8-12/11) allowing the
IPA switching power supply to provide an IPA volts
supply to the IPA module. When the
RF OFF
condition is enabled (locally or remotely), the exciter
interlock will mute the exciter's output, the
RF ON
indicator LED will turn off, the remote RF on status
is disabled (open circuit), J6-6 will switch to ground
(
RF On
) causing the low voltage power supply to
remove the 24 VDC supply from the cooling fans and
an inhibit (ground) will be placed on the
IPA Volts
Control
output (J8-12/11) to turn off the IPA
switching power supply and inhibit the transmitter
RF output. The
Alarm Reset
signal (J9-10) is
activated (5 VDC) during the RF on condition to
prevent false alarm indications.
6.5.2.5
Transmitter Interlock:
See figures SD-9
and SD-10. The transmitter safety interlock circuit
will influence the RF status to prevent transmitter
operation when the interlock is open. If the interlock
circuit is opened, the
INTERLOCK OPEN
indicator
LED will turn on and the
RF ON
indicator LED will
turn off or remain off. The circuitry will function as
if the
RF OFF
switch had been pressed (see para
.6.5.2.4). 5 VDC will be applied to the
Alarm Inhibit
line during the interlock open condition to prevent
other transient alarms. When the interlock circuit is
closed,
INTERLOCK OPEN
indicator LED will turn
off when
ALARM RESET
is momentarily pressed. If
the RF was on previous to the interlock being opened,
the
RF ON
indicator LED will turn on and the RF
output will be exponentially restored to its previous
level.
6.5.2.6
Transmitter Output Power Level
Adjustment:
See figures SD-9 and SD-10. The
magnitude of the low level DC
PA Volts Control
output (J6-1/3) determines the output voltage level
applied to the RF power modules (A thru F) from the
switching power supplies (A thru F) and hence the
output power level of the transmitter. This voltage is
generated by a counter circuit and a digital to analog
converter which allows adjustment of the control
voltage from a minimum of 0.0 VDC to a maximum
of approximately 7.5 VDC in 256 discrete steps.
Each time the
POWER RAISE
switch (A13A1S8) is
momentarily pressed, a ground is applied to the
Pwr
Increase
input (J2-39) and is detected by the counter
circuit. The counter circuit's total count will increase
by one (until a maximum count of 256 is reached
corresponding to maximum output power) and the
transmitter's output power will increase by the
corresponding increment. If the
POWER RAISE
switch is pressed and held, after a brief pause the
transmitter's output power will begin to continually
increase until the
POWER RAISE
switch is released or
until maximum output power has been reached. Each
Summary of Contents for FM10
Page 173: ...Figure SD 1 Electrical Schematic FM10 FM Broadcast Transmitter Overview Page SD 1 15 July 1997...
Page 174: ...Figure SD 2 Electrical Schematic AC DC Power Supply Sheet 1 of 2 Page SD 2 15 July 1997...
Page 175: ...Figure SD 3 Electrical Schematic AC DC Power Supply Sheet 2 of 2 Page SD 3 15 July 1997...
Page 177: ...Figure SD 5 Electrical Schematic 3 Phase Monitor PWB NAPC60 03 Page SD 5 15 July 1997...
Page 178: ...Figure SD 6 Electrical Schematic RF Power Stage Sheet 1 of 2 Page SD 6 15 July 1997...
Page 179: ...Figure SD 7 Electrical Schematic RF Power Stage Sheet 2 of 2 Page SD 7 15 July 1997...
Page 180: ...Figure SD 8 Electrical Schematic RF Combiner Final Filter NAF79 Page SD 8 15 July 1997...
Page 181: ...Figure SD 9 Electrical Schematic Control Monitor Function Page SD 9 15 July 1997...
Page 182: ...Figure SD 10 Electrical Schematic Control Display PWB NAPD05 01A Page SD 10 15 July 1997...
Page 185: ...Figure MD 1 Assembly Detail FM10 FM Broadcast Transmitter Front View Page MD 1 15 July 1997...
Page 186: ...Figure MD 2 Assembly Detail FM10 FM Broadcast Transmitter Rear View Page MD 2 15 July 1997...
Page 189: ...Figure MD 5 Assembly Detail NAG02 01 NAG02 02 Circuit Breaker Panel Page MD 5 15 July 1997...
Page 190: ...Figure MD 6 Assembly Detail NAC76 Power Supply Control Panel Page MD 6 15 July 1997...
Page 192: ...Figure MD 8 Assembly Detail NAPD05 01A Control Display PWB Page MD 8 15 July 1997...
Page 193: ...Figure MD 9 Assembly Detail NAI07 Intermediate RF Drive Splitter Page MD 9 15 July 1997...
Page 194: ...Figure MD 10 Assembly Detail NAFP68 IPA Input Power Probe Page MD 10 15 July 1997...
Page 196: ...Figure MD 12A Assembly Detail NAS43 02 Low Voltage Power Supply Page MD 12A 15 July 1997...
Page 197: ...Figure MD 12B Assembly Detail NAS43 02A Low Voltage Power Supply Page MD 12B 15 July 1997...
Page 199: ...Figure MD 14 Assembly Detail NAPC60 03 3 Phase Monitor PWB age MD 14 15 July 1997...